The Mycelial Network

Green Eggs and Zipf's Law

2020-12-31T11:11:00.000-08:00

In the 1930s and 40s American linguist, George Kingsley Zipf wrote about a pattern found in written texts. Now known as Zipf's Law, the pattern shows an eerie similarity in the distribution of word frequencies across essentially all documents whether they are books, essays, short stories or letters. If you take a given set of words, count up all the words and order them by frequency you will find that the second most common word occurs almost exactly half as often as the first. You will also find that the third most common occurs one third as often as the first, the fourth most common occurs one fourth as often, the fifth one fifth and so on with each word occurring 1/n as much as the most common word where n=its place in the order.

Pretty neat and pretty weird but as researchers from different disciplines began to look for distributions in other data sets we started seeing the same pattern everywhere. City populations, website traffic, citations of scholarly articles, deaths in wars, TV ratings. How long you remember things follows this pattern. Even randomly generated texts follow Zipf.

We don't fully understand why language follows Zipf's law but the basis of why all these very deliberate, human systems follow the same pattern is somewhat simple: human behavior, even the extremely complex nature of cities and global societal behavior, are still governed by natural laws, and ultimately, math. Even something like the population of a city which is governed by what feel like very personal decisions like taking a job, moving to be closer to family, etc. are subject to the ebbs and flows of pure numbers: the means and variances of statistics will, given time, determine the number of people living in a distribution of cities either in a country or in the world.

This is similar to another statistical idea: the Pareto principle, named for Italian economist, Vilfredo Pareto. It states that 80% of a given system's consequences are due to only 20% of that system's causes. More concretely, Pareto discovered that 80% of land in Italy was owned by 20% of people. This too has been applied to countless human systems: business managers will tell you that 80% of revenue will come from 20% of clients, IT departments and software engineers know that 80% of computer crashes come from 20% of the bugs, and 20% of your carpet endures 80% of the wear.

When I first learned about Zipf and Pareto my mind eventually went to the stark wealth inequality that exists in the US and in the world. Do these seemingly ubiquitous natural laws mean that we are locked in to the current state of affairs with roughly 20% of people controlling 80% of the world's resources? But that's when I found a way out: Dr. Seuss.

Famously, Theodore Geisel, known better by his pen name, Dr. Seuss, wrote the book Green Eggs and Ham on a bet that he couldn't write a book using only 50 words. This bet produced one of the great children's author's most enduring classics. I wondered: could this fairly extreme constraint get around Zipf? I counted up all the words and plunked them into Excel. And this is what I found:

Green Eggs and Ham does not follow Zipf! Just looking at the first few words "not," "I," and "them" you can pretty clearly see that the second and third appear much more frequently than the 1/2 and 1/3rd that of the first. It's not even really close. Another way to look at these data is that a Zipf distribution should be an almost perfectly straight line with slope = -1. This line, especially after you get to "could" is no where near a straight line, it's a gentle slope towards the last word at that point.

Green Eggs and Ham gives me hope. If we just let systems motor along as they are, we'll inevitably end up with Zipf. But if we manage to figure out a way to put some creative constraints on our larger systems, it looks like we may actually be able to push them towards equity. I'm not remotely saying that will be an easy task but with the right tweaks, the right concerted effort in the right direction we might be able to pull a Zipf distribution into something a little more even. I do so like green eggs and ham! Thank you! Thank you, Sam-I-am!

Sources:

https://upcommons.upc.edu/bitstream/handle/2117/180136/Ferrer-i-Cancho_EPJB_2005.pdf;jsessionid=0AA5762D175B3844791253058CFB645F?sequence=1

http://pdfs.semanticscholar.org/5a9a/0438af964d00249bafff11f0e85ef924a61a.pdf

http://pages.stern.nyu.edu/~xgabaix/papers/zipf.pdf

https://www.researchgate.net/profile/Wentian_Li/publication/253290454_Zipf's_Law_Everywhere/links/5cf59ef9299bf1fb185617ff/Zipfs-Law-Everywhere.pdf

https://www.biography.com/news/dr-seuss-green-eggs-and-ham-bet

https://betterexplained.com/articles/understanding-the-pareto-principle-the-8020-rule/

Vsauce: https://www.youtube.com/watch?v=fCn8zs912OE

Seuss, Dr.. (1960). Green Eggs and Ham. New York, NY: Beginner Books.

A Very Brief History of Earth and its Water

2020-07-14T10:48:00.004-07:00

This story begins about 4.5 billion years ago. Things were pretty boring in our solar system for a while. Space dust had been floating around, gravity slowly gathering it into slightly larger clumps, for a time but what we needed to get things moving was some external kick. Probably a nearby star exploded, or some large object came whizzing in to stir things up but whatever it was gave a nudge that allowed gravity to pull all that dust into the major objects that we recognize today: the sun, the planets and most importantly for this story, the large rocky object where eventually some apes would evolve and name "Earth" (among other names).

For a long time the Earth looked like this:

Image: Tim Bertelink CC BY-SA 4.0

There are a few theories about where all the water on our planet came from. One is that during the time depicted above, known as the Hadean, the water was already there. It would have been entirely in the form of water vapor because it was extremely hot but it was around. As the Earth cooled it would have condensed into a liquid, formed clouds, precipitated out of the atmosphere and started to do all the great things we can rely on water today for.

Another theory is that when the Earth formed there was little to no water and we got it from some external source. It might have come from a comet or an asteroid or a series of smaller asteroids. This probably all happened pretty early on in the Earth's history. We can find clues to where the water on Earth came from by looking at the percentages of the isotopes of hydrogen in the water molecules. An isotope is a chemical element that has a different number of neutrons in its nucleus and in this case the stable isotopes of hydrogen can have either zero or one neutron. Scientists today are still collecting samples, analyzing the data and running statistics to try to understand where all the water on our planet came from.

Regardless of where it came from eventually Earth did get water on it, most of it in our one large ocean covering about seventy percent of the surface. Side note: I did say "one ocean." This may be splitting hairs but while most of us are taught that the Earth has a few separate oceans there is only one big body of water that covers the planet. Check out this ArcGIS render of a map by the artist Athelstan Spilhaus:

Everything is connected and you could, in theory, take a boat to any point in the ocean without having to hop out onto dry land.

Anyway, one of the next major events in the history of Earth's water is how it got salty. It did not actually come that way! This bit is fairly straightforward: as the water cycle started to get revved up and rain became a thing we got lakes, ponds and also rivers. All those rivers meant a lot of runoff into the ocean. As water flowed down river it brought sediment with it and in that sediment were a bunch of different salts. Over the millions (and millions) of years that this process continued we eventually ended up with the salinity we currently see in our ocean. Thanks runoff, now I can do a full body float when I go to the beach!

While salt water plays an absolutely enormous role on the Earth's biosphere and climate, its the fresh stuff that we humans and other terrestrial animals need to survive and unfortunately it's much more limited.

You can click to embiggen: the big blue blob represents ocean water, the little blob to its right is all the liquid fresh water and the every tinier blob next to that (which is...really hard to see) is fresh water in lakes and rivers. This water, known as "surface water," is all that is available to us to use as drinking water and water to cook and clean with. It's not very much!

So it's important for us to get together and conserve and protect our fresh water resources. One fun thing you can do is check out your local watershed conservancy, association, council etc. Pretty much wherever you live there is a river near you. A lot of these organizations host clean ups and fun events like festivals and bike rides to get people out there appreciating and connecting with their local waterways. While a lot of those kind of events may be on hold right now, you can still get out there and appreciate the nearest river, lake, pond or stream.

https://www.livescience.com/33391-where-did-water-come-from.html

https://www.iflscience.com/physics/origin-earths-water-discovered-0/

Why Are Planetary Orbits Elliptical?

2020-05-22T14:08:00.000-07:00

I hope everyone enjoys my Extremely Fancy images on this post. I built most of this myself and I a) don't have the best technical art skills and b) lack any actual graphics software. Someday hopefully we can afford a graphics department. :)

It may seem like planetary orbits and orbits of other objects should be circular. Circles are simple and many patterns in nature adopt a roughly circular shape. However there are two factors that dictate a planet's orbit that will help us understand why orbits are elliptical and not circular.

Just be sure we're on the same page, an ellipse is what we usually call an oval. This is an ellipse:

The two dots are the ellipse's foci (I just sort of ballparked it here). The exact math and concept of what foci are is a bit outside the scope of this post but you can think of it this way: a circle is a special case ellipse in the same way that a square is a special case rectangle. In a circle the two foci overlap and are at the center. The more stretched an ellipse is, the further away from the center of figure they will be (yes, this is a simplification). You can also check out this neat little demo to get a sense of how the placement of the foci dictate what the ellipse will look like.

Let's also get a little bit of possible confusion out of the way. The way you often see Earth's orbit drawn in text books or diagrams looks a bit like this:

There was a time when I was hearing people talk about the idea that Earth's orbit was actually circular and that the way it's drawn in textbooks is highly exaggerated. This is sort of half true. The way it is drawn is often exaggerated but the orbit is elliptical. It's just not all that elliptical. How elliptical an orbit is can be described with a measurement called eccentricity which goes form 0 to 1 with 0 being a perfect circle. Earth's orbit has an eccentricity of about 0.0167. So rather than the very noticeably elliptical path in the image above it's closer to something like this (again, ballparked):

To see why planets have elliptical orbits we need to take a look at what happens when two massive objects interact in space. We're going to keep the systems to two objects for simplicity and we're also going to imagine one object is stationary and the other is moving towards it. Neither of these things is really what you see in space as objects are all hurtling around towards and away from one another constantly but it gives us a nice clean system that should hopefully make things relatively straightforward.

When one object approaches another in space there are two forces acting on the object: its own momentum and the force of gravity attracting the two objects. There are a few different things that can happen depending on how strong these two forces are. If an object has a very high momentum and the gravitational attraction between the two objects is fairly low, the path of the object will be bent but it will not be "caught" in an orbit. The red arrow represents the object's momentum and the blue arrow, gravity, resulting in the purple arrow. These arrows will change as the object proceeds on its path but hopefully this illustrates how this combination of forces will result in the path shown:

The second possible outcome is that the force of gravity is quite high and the momentum quite low. This results in the smaller object crashing into the larger.

When we have a situation in between these two extremes, when the momentum and force of gravity are relatively in balance, this is when the smaller object is "caught" and falls into orbit around the larger. We're going to visualize this to see why the orbit will be an ellipse. We're going to look at a relatively extreme (high eccentricity) shape compared to Earth's orbit but this situation still applies to our planet. I'm also going to change the orientation so we can visualize the formation of an orbit as the smaller object *falling* into the gravitation field of the larger. This is not really a metaphor, as we'll see. Orbits are a type of falling...they just don't end up in a crash. At least for a great many billions of years. I'm also going relabel the larger object "object A" and the smaller object "object B." OK here we go!

I put numbers on a few points in object B's new orbital path to try to break down what's going on. Imagine at point 1 that object B is hurtling along in space but it has begun to get close enough to object A that their gravitational attraction is going to start to change its course. As it moves toward point 2 its initial momentum has it wanting to continue on its original path but gravity now has it on a path falling towards object A. As B moves towards point 3 gravity is getting stronger, accelerating it, but because it maintains momentum, it does not crash here but instead moves on a curved path along the "bottom" of object A. As it moves "up," away from the "bottom" of the orbit here gravity is now going to decelerate object B. I removed the other force arrows at point 4 because the important point here is that its momentum is carrying it "up," away from object A but gravity is still pulling towards object A. Object B decelerates until it reaches the "zenith" of the orbit at point 5 where it then begins to fall again back towards object A.

You can think of this a bit like tossing a ball into the air in an arc from one hand to the other. As you put a force on the ball it rises but is decelerated by Earth's gravity. As it reaches a zenith it's upward velocity momentarily becomes 0, then it is accelerated by gravity, falling back down to your other hand.

So why can't this system form a circle? Well...actually it can. It's just extremely unlikely. In order for the orbital path to be a perfect circle the balance between the momentum and gravity need to be exactly matched and at exact right angles as it is caught in orbit. This is what that would look like:

Imagine the smaller object moving towards the larger and it's position and momentum enter the orbit at the top of this diagram. Right at this moment, the force of the momentum and the force of gravity would have to be exactly the same and exactly at right angles to one another to create the perfect 90 degree arc, bringing it to the point to the right of the larger object, at which point momentum and gravity are still exactly matched and exactly at right angles, continuing neat 90 degree arcs all the way around.

Sorry for holding out on you: circular orbits can happen and do happen. They're just very, very rare because the conditions you need for them to form are exceedingly unlikely. Think back to the analogy of throwing the ball in an arc from one hand to the other. Imagine how unlikely it would be for you to get that ball to go in an exact semicircle. The force and direction you apply to the ball with one hand would need to be super precise for this to happen. It's not hat you couldn't ever get a ball to fall into a perfect semicircle, it's just that you would have to be extremely lucky or try over and over again. And remember, while Earth's orbit is an ellipse, it is actually pretty close to a circle.

Except! There is one little caveat. I've simplified a lot here but one thing I've glossed over a bit is that gravity is a force that attracts two objects together. It doesn't actually pull object B towards object A, it pulls them towards one another. Now obviously with objects that differ in mass by extremes like the Sun and Earth or the Earth and a ball, the acceleration on the smaller object is going to be much, much more noticeable. But there is a non-zero acceleration on the more massive object.

One of the things that this means for orbits is that smaller objects don't actually orbit larger objects. They orbit each other. The point where they orbit one another is their center of mass. You can think of this as the point at which the combined mass of both objects is equal on both sides. The center of mass also represents one focus (remember our ellipse's foci at the very beginning?) of an elliptical orbit. While the Earth is a large object, the Sun is much much more massive so for our orbit the center of mass is actually pretty close to the center of the Sun. Again, I'm totally ballparking this and completely simplifying but just to illustrate:

Warning! Not remotely to scale!

Even if Earth's orbit wanted to be a perfect circle (err...conditions were lined up exactly perfectly so the momentum and gravitational forces were balanced and at exact right angles), that tiny shift in where the objects orbit one another would mean it would still end up as an ellipse. Just by being two massive objects orbiting one another and having a center of mass they introduce eccentricity into the orbit.

Now, for an object the size of Earth, the eccentricity introduced due to the center of mass not being at the very center of the Sun is pretty small. For something like an asteroid that is 100th or 1,000th the mass of Earth that eccentricity is going to be...not even measurable. We're talking ten, thirty, fifty decimal places out. It's not zero but it's tiny. But it's always going to be there. Even in a system where the momentum and gravitational forces are lined up just right, the center of mass of the system is going to introduce, at the very least, a tiny amount of eccentricity into the system. So even in the most unlikely, perfect situations, we're never going to get an exactly perfectly circular orbit.

This post was super fun and I did a ton of research. I hope you enjoyed it! As with other topics, I'm not an expert but this definitely took me out of my comfort zone. If you have comments, corrections, questions etc. please drop them in the comments or tweet at me @paulsfenton.

Thanks for reading!

Sources:

email correspondence: Richard Binzel, Professor of Planetary Science, Joint Professor of Aerospace Engineering and MacVicar Faculty Fellow, Massachusetts Institute of Technology

https://www.scienceabc.com/nature/universe/planetary-orbits-elliptical-not-circular.html

https://www.youtube.com/watch?v=DurLVHPc1Iw

https://www.youtube.com/watch?v=xaCyQvwJ_Vs

https://www.youtube.com/watch?v=59qniggFpFQ

https://www.quora.com/Why-are-planets-orbits-elliptical-Why-not-circular

https://www.windows2universe.org/physical_science/physics/mechanics/orbit/eccentricity.html&edu=high

https://www.education.com/science-fair/article/orbital-eccentricity/

https://gravity.wikia.org/wiki/Orbital_eccentricity

https://everything.explained.today/Circular_orbit/

https://everything.explained.today/barycenter/

https://physicsabout.com/keplers-laws/

https://www.quora.com/What-causes-comets-on-an-elliptical-orbit-to-return-to-the-sun-Theres-no-friction-in-space-and-the-comet-should-keep-going-out-of-the-solar-system

Are Viruses Alive?

2020-04-24T12:01:00.002-07:00

I'm getting pretty tired of content about SARS-CoV-2/novel coronavirus/Covid 19. I mean, we all need the best, most up to date public health information we can get so we can all do our part to keep one another safe and healthy and get through this thing. But it feels like the radio and several TV shows are just...all Covid 19 now.

So while this post is going to be about viruses, it's not about SARS-CoV-2. And while the title asks the admittedly click-baity question "are they alive?" I'm not actually going to try to answer that question. I'm more interested in taking a look at what we mean when we say "alive." I love to poke at what happens when we find things outside the neat categories humans try to put things into. "Alive" may be the category nearest and dearest to our hearts and possibly one of the easiest to poke holes in.

What exactly is a virus? I think we can safely define them like this: they are organic (regardless of whether they are alive or not) structures that can replicate using either DNA or RNA (a molecule similar to DNA used by most living things). To do so, they "infect" a cell, basically breaking through the cell's membrane or outer layer of defense against the outside world. They then hijack the molecular machinery the cell uses to replicate and begin to generate copies of themselves.

Like most things in biology (and probably all science), defining "alive" depends on who you ask. But it seems that most of us agree on a few characteristics: 1. It can reproduce (on it's own) 2. It has cells 3. It obtains and uses energy 4. It grows and 5. It can sense/move in response to/adapt to the environment.

There are a couple of go to arguments against viruses being alive based on this list of characteristics. Let's get the easy one out of the way: viruses don't have cells. Cells always have some sort of barrier that creates an "inside" and separates it from the "outside." For a lot of folks this is a dealbreaker: no "inside" and you can't be "alive," you're just a part of the environment. I've got a few issues with this, two I'll handle now and one I'll come back to. First, as organisms get more complex what is "inside" becomes less clear. Think about this: there is a passage that goes straight from your mouth to your anus. You aren't a a cylinder, you're a tube. Secondly, though maybe this is more opinion than fact, I just feel that saying "cells or bust" is a bit arbitrary. Imagine we found something that could reproduce, takes things in, spits things out but didn't have a cell (spoiler, we'll meet one of these things in just a bit). I'd be inclined to at least consider that these things are alive. Especially if you consider using DNA or RNA as a form of coding which not just allows it to reproduce itself but allows for mutations (changes due to the environment or a mistake in reading the code), that allows for changes across generations and therefore evolution. I would not be at all surprised if when we find life on another planet it did not have cells.

Probably the most popular argument against viruses being alive is that they can't/don't reproduce on their own. Again I've got a bit of a quibble with this: parasites. Most parasites cannot survive, let alone reproduce without their hosts. I have never heard anyone argue that because a parasite cannot survive or reproduce on its own this disqualifies it from being alive, yet it seems that many throw this line of argument out for viruses and expect the case to just be closed.

If we take a look back at the list of characteristics of life I also think that 4. It grows may also be a bit arbitrary. In fact single celled life doesn't really grow, at least not in the sense that multicellular life does. Bacteria and other single-celled organisms reproduce by dividing one cell into two. While there are stages in the processes that you might call "growth" it's definitely not the same as an organism being born, taking in nutrients, going through development and its body getting bigger.

Let's go back to the idea that to be alive you need to have a cell. Pretty recently we've found proteins that can, at least in lab settings, reproduce and create amino acids (molecules that are the building blocks of proteins which make up, well, most of everything alive). I'm not going to argue that these proteins are living things but I am going to argue that they represent a possible glimpse into the beginnings of life on earth. We know that in the history of earth there was a time when we went from no life to having life and that there was some process that allowed organic molecules like amino acids and proteins to eventually become "alive." What I will argue is that this is a spectrum. Rather than "alive" and "not alive" I think we can look at this as an evolution from inorganic molecules to organic molecules to RNA and DNA to cells to more complex organisms. Even in the most complex vertebrates like ourselves, everything happening in our bodies is chemistry. I don't necessarily know that you can draw a sharp line between chemistry and biology here. [To be clear: I'm not trying to argue here that organisms like us with lots of cells and tissues and organs are "better" or "more advanced" necessarily; we just came later in the story]. So going back to viruses: they also contain organic molecules like RNA and DNA and so, I think, could be considered a part of this spectrum of organic structures.

I think it's really interesting when one category starts to bleed into another like this: when inorganic becomes organic, when chemistry becomes biology. Our human categories really start to break down almost every time we look at a transition in evolution between two groups. When you look at the evolution of plants, for example, you have mosses which are considered plants by most but don't have stems or leaves which are generally considered things all plants have. But we don't always see these rule breakers at the evolutionary transition points. The platypus is a famous example of a mammal that does not give birth to live young. It isn't an evolutionary descendant of other mammals, it's just a different branch on the tree. Even the notion that all animals require oxygen has recently been overturned with the discovery of a species living in a completely oxygen-devoid part of the Mediterranean.

As we've seen we can form categories for living things by coming up with a list of characteristics, looking to see if we've got all of them and then if it does, put it in that category. As we've also seen, that doesn't always work. The other way we can form categories is through evolutionary relationships. If two things share a common ancestor (they evolved from the same species or, maybe in some cases, the same molecules) then we can put them in the same category. That's why we consider platypuses to be mammals: they don't give live birth but they do share a common ancestor with other mammals. Just like you and your cousins, platypuses and other mammals share the same stock, they're part of the same family regardless of characteristics. Recently, some analysis of the shapes of proteins in viruses indicate that they may in fact share common ancestry with cellular life. This is super preliminary but if more evidence starts to stack up and we become more confident that viruses and cellular life evolved from the same early organic chemical reactions on earth, I would be willing to say that viruses and cells are in the same category. Maybe still not alive. Maybe, the cousin of alive.

Sources:

https://bmcbiol.biomedcentral.com/articles/10.1186/1741-7007-8-30

http://www.bbc.com/earth/story/20170125-there-is-one-animal-that-seems-to-survive-without-oxygen

https://www.popsci.com/new-evidence-that-viruses-are-alive/

https://www.sciencedaily.com/releases/2015/09/150925142658.htm

https://advances.sciencemag.org/content/1/8/e1500527

https://www.sciencealert.com/amyloid-protein-self-replication-abiogenesis-contrasts-rna-world

Exploring Nature at Home

2020-04-20T12:19:00.000-07:00

We're only a few days away from the 2020 City Nature Challenge and obviously this year is going to be a little bit different. You can visit their website, and specifically this page, to learn about what is changing and what isn't.

Unsurprisingly, while we are still going to try to get out and collect as many observations as possible, we will be doing this while social distancing. For many of us this will mean observing the natural world in patches of green space in our neighborhood, our back yard or even just from our windows. The other big change is that this year will not be a competition and some of the organizers are using the phrase "City Nature Celebration." They also put together this guide on exploring nature at home.

I also recently wrote about exploring the natural world at home, even if it means you can't or don't feel comfortable going out into your neighborhood and wanted to share that here.

Even though we may be spending most of our time at home there are still ways to explore nature with your family! Whether you are able to get outside to a park, green space, yard or you can only make observations through windows or from a porch there are lots of options for looking closely. Here you will find resources, tips and ideas for you and the young people you care for to engage with the natural world!

The Big Picture

No matter where you are exploring there are a few basic tips and tricks for helping young people explore the natural world you can always rely on:

Look closely and ask questions: what colors do you see? What do you think this animal is doing? How many legs does it have? How many trees can you see? What do you think we might find next? What is the weather today?

Record what you find: use whatever paper and writing tools you have available at home to keep track of what you find and notice. If you have the ability to hang pieces of paper or keep your observations in the same notebook over time that can provide an opportunity to look back and talk about what patterns you see, what is always the same and what changes. But if not, just the act of drawing or writing down your observations is a great way of focusing attention and solidifying observations in memory.

Window Observations

This is a simple, flexible activity you can use to connect with the natural world even if you don’t have access to green space at or near your home. As written, you make observations through a window but you can also take a short walk through your neighborhood, go to a yard or park, if you are able, to make observations. Try both and see what differences you notice between the window and your walks!

What you need: a window (optional: chart paper or any smaller kind of paper, pen/pencil/marker/etc, book or online field guides [see web links below], binoculars).

What you do: Choose a window, or several windows, where you can see a variety of plants, animals and weather. This activity can be done with a single observation or over the course of days, weeks, months or even years. No need to plan ahead if you don’t want to commit, though. If you are using paper to record what you see, get out your paper and something to write.

Here are some things to look for and guiding questions as you observe:

Start off open ended: what natural things do you see? What colors do you see? Trees, animals, weather, sky, clouds, rocks? Start to get acquainted with your window or the section of your neighborhood you have chosen to watch.

· What is the weather like? Recording weather across a week, a month, or a longer period of time and then going back and looking for patterns or trends (does the temperature go up each day, down each day, up and down? How many days were sunny vs. rainy vs cloudy?) is a great but very simple way to engage with the natural world.

· What animals do you see? Don’t worry about having to identify species at first. Squirrels? Birds? Can you describe them? What colors are they? What do you see them doing? Are they big, medium or small?

· As you get to know the animals outside your window or in your neighborhood you can start to use field guides to identify what species they are.

· What trees and other plants do you see? Like animals, don’t feel you have to know the specific species at first. Are they tall or short? Do their branches go up or out? Do they have leaves or needles?

· Don’t forget rocks! Rocks will be a little trickier to identify from afar but go back to those open ended observations: what sizes do you see? What colors? Try to challenge your young people to get more specific than “gray” or “brown.” Light or dark? Greenish gray? Try to get them looking and thinking as closely as possible.

· If you’re able to be up after the sun sets (and it is safe for you to do so), try making some observations after dark. What are some things you notice that are different? What’s the same?

· If you choose to continue making observations over many days, choose a time (maybe each week?) to go back and look and what has changed over time. Are you noticing different animals across the weeks? Do you notice different behaviors? When do plants grow, lose their leaves, grow their leaves? What patterns or trends have you noticed in the weather?

Identification Guides for Window Observations

Mass Audubon Insects and Arachnids: https://www.massaudubon.org/learn/nature-wildlife/insects-arachnids

Mass Audubon Birds: https://www.massaudubon.org/learn/nature-wildlife/birds

Mass Audubon Mammals: https://www.massaudubon.org/learn/nature-wildlife/mammals

Tree Identification by Bark: http://www.trees-id.com/bark-1.htm

(For Plants) Go Botany Simple Key: https://gobotany.nativeplanttrust.org/simple/

Identifying Clouds: https://gewa.gsfc.nasa.gov/clubs/sailing/IMAGES/MISCELLANEOUS/CloudChart.pdf

Exploring for Nature Inside

What you need: you can explore inside or outside your house for insects and other invertebrates without using any special materials. If you have a small jar or Tupperware container at home that can be helpful to place small creatures for viewing but it’s just as easy to observe them where you find them!

Just as with window observations, you can add a record, note-taking or drawing component to help your young people look closely, find patterns and ask questions about longer-term animal behavior.

While not everyone agrees that they are the most welcome inhabitants, most of our homes are also inhabited by a range of insects, spiders and centipedes. Hunting for these smaller animals in your basement, attic, bathroom or other out-of-the-way areas is another great way to engage with nature without leaving home! While these creatures may not be the most popular, it is perfectly safe to explore for them. There is only one potentially dangerous species of spider in Massachusetts, the very distinctive black widow. While you are unlikely to encounter it (these spiders are much more common in the South and West United States) you can find information about identification and their behavior here.

Identification and Resources for Bugs in Your Home

http://robdunnlab.com/projects/arthropods-of-our-homes/learn-more-about-your-arthropods/

https://www.vox.com/science-and-health/2016/1/23/10815572/insects-species-home

Exploring for Insects and Other Invertebrates in Your Yard

What you need: As with exploring inside, this can be a very engaging activity without any materials. If you happen to have a small shovel for digging into the soil that can help find certain creatures, especially earthworms and insects that winter in the soil. Again, a small jar can help keep creatures in place to view them but is not necessary for observing outside.

If you are able to explore a yard, park or other green space in your neighborhood you are likely to be able to find not only birds, squirrels and other vertebrates [animals like birds, mammals and reptiles that have a backbone], but also a host of smaller invertebrates [animals without a backbone like insects, spiders and snails] hiding on plants, under rocks and logs and in the soil. Here are some resources for how to best find these smaller creatures all around us.

https://www.wikihow.com/Catch-Small-Bugs

http://www.bugcollectors.com/where-to-find-insects

Scientific Consensus and Uncertainty

2018-12-12T07:58:00.001-08:00

There is a line of thinking, you may have encountered it, that says something to the effect of "there is no such thing as consensus in science." The argument goes that in science we never prove, only disprove and we are always discovering, learning, tweaking and we should always be holding what we believe to be true, especially the theories and laws most dear to us, with skepticism. Therefore, we should not or cannot ever have consensus. There should always be room for debate in science and consensus is a tool of the powers of authority to stop those that would challenge this authority.

The real difficulty with this line of argument is that it takes something that is true and good about science (that we only disprove, that we constantly amend our theories when new observations or information is collected, that we should remain skeptical) and takes its logical end creating such epistemological relativism that would dictate we can never know anything or ever do anything with that knowledge. Which is demonstrably not the case. We do know things and we do things with this knowledge.

Let's think about how this applies to engineering. We've studied steel. Steel is great; it's fairly plentiful (rather it's components are), it's very strong, it's relatively easy if somewhat energy intensive to make stuff with. So we have an idea: let's build stuff with it! Let's use it to build some buildings! Modest at first but eventually, maybe we can build some really tall buildings! Now if your position is really that we cannot build scientific consensus you'll say: "No, no! We need to continue to learn about steel! Perhaps there is some hidden property that we're unaware of that would make it unsafe to build with! What if there is an as-yet-undiscovered reaction that occurs when it reaches a certain elevation that makes it impossible to build tall buildings with?" But we do build with steel. We've reached a level of confidence that allows us to say "we know enough about this material, we understand its properties, let's move on and do some engineering with it."

While it is true that nothing in science is ever proven in the strictest sense, confidence is a technical term for how statistically likely it is for future experiments or observations to hold with past experiments and observations. So while we might not have proven that steel is a good building material, the statistics are very much in our favor.

We also do have what we call scientific facts. A fact is a piece of knowledge that, again, has been tested over and over and over to such an extent that statistically we have very strong confidence that it is for practical purposes "true." One of the go to examples of this would be if you hold an object in your hand (that has greater density than air) and let go of it, it will fall. Steel's high strength is a fact. Atoms consist of protons, neutrons and electrons: fact. Now could we discover new aspects of the natural world that counter these observations? We could. It's just very, very unlikely.

"Ah!" Says the anti-consensus line of thinking. "But in science there is no "truth." We've been wrong before and we could be wrong now!" Yes, many many scientific facts, laws and theories that were consensus for very long periods of time have not held up to the scrutiny of the scientific method and new evidence. It's quite true. We once believed in something called "the aether," a substance through which light waves could propagate. It doesn't exist; we now know that light and other electromagnetic waves are self-propagating. We once believed there was a substance called "phlogiston" within all combustible materials. We had lots of evidence based on observation and experiment that such a thing existed. It turns out we were wrong.

Scientists and consensus can get locked into what is "accepted" and fail to pick up on evidence that would lead us to new theories, facts and laws that better explain our observations. This is a very real aspect of the scientific method. But saying that we cannot ever have enough confidence in our observations to do anything with them is throwing the baby out with the bath water. And, again, demonstrably false. Engineering is nothing but taking scientific facts, measurements, theories, etc and applying them. We reach consensus whenever we build new infrastructure and technology. Whenever we develop medicine (and yes, sometimes we make mistakes) we are reaching consensus. When I know that jumping from a great height is a bad idea because gravity will accelerate me quickly to the ground and severely injure or kill me, I'm working with scientific consensus.

You may see this argument applied to climate science and climate change. That because science never proves anything, saying that there is a consensus is antithetical to the scientific method and merely serves to silence dissenters. It prevents us from making new discoveries. But here's what we know: it is a scientific fact (in the technical sense) that carbon dioxide and other gases trap heat in our atmosphere. It is a historical and scientific fact that humans have added a bunch of rampant carbon dioxide to Earth's atmosphere. Therefore, we can infer (and have measured) a rise in average atmospheric and sea surface temperatures. We have observed ice that has existed since humans have melting. We have a very, very high level of confidence in these things. And we have a very high level of confidence that Earth's atmosphere will continue to warm and that this will have other effects on our climate.

Do we know exactly what will happen with the climate? No, of course not. We have some decent models but there are a host of variables we can't predict very well (mainly the social variables, i.e. what are humans and governments going to do as we move into the coming decades). Humans are notoriously difficult to predict. But just because we don't have a perfect climate model with extremely high confidence doesn't mean we don't still have some basic facts that allow us to act in a logical, reasonable way.

Good scientists are always skeptical, always open-minded. Good scientists do their best to truly think critically and examine if their observations are in conflict with what they believe. But good science also allows us to create, to heal, to feed, to protect. Good science allows us to act and not only study.

Sources:

Kuhn, Thomas. The Structure of Scientific Revolutions. Chicago and London: The University of Chicago Press, 1962.

https://www.visionlearning.com/en/library/Process-of-Science/49/Uncertainty-Error-and-Confidence/157

https://eic.rsc.org/feature/the-logic-of-phlogiston/2000126.article

https://ncse.com/library-resource/definitions-fact-theory-law-scientific-work

The Speed of Light and Time Dilation

2018-08-11T05:20:00.002-07:00

So light is fast. But its speed isn’t necessarily special. It just travels at the highest speed the universe allows. Photons (the particles of light) have no mass so, like all things without mass, they have nothing to slow them down. So off they go as fast as they can! Why is there a universal speed limit? The answer to this is, like other questions about the fundamental nature of the universe and laws of physics, we simply could not exist in a universe with infinite speeds. There are two things that would go wrong for us: 1. It would take infinite energy to give something mass and so things with mass (like us) couldn’t exist. 2. Time (or to be more precise, really, space-time) wouldn’t exist. Light travels at the fastest speed a signal can be sent in our universe. Because we have a finite signal speed it means that events have distance and time between them. This is quite odd to say, but an infinite speed of light or infinite signal speed would mean that there are not distances and times between events. How would a particle with infinite speed actually behave? A signal (or particle) with infinite speed would exist everywhere in the universe at once. These particles would never take any amount of time to go anywhere and would never need to travel anywhere because they all would already be everywhere forever. So while such a universe could exist we wouldn’t be around to observe it. Nothing, really, would be around.

Because the speed of light is always at the fastest possible speed the universe allows this has a weird byproduct: light’s speed is not relative to the observer. It is always the same. Here’s a little more detail about what that means and following, a little about why that’s weird. Imagine someone on a train car going 100 km/h, you’re standing still watching the train car go by. Now imagine they throw a ball at 50 km/h. From their perspective the ball is going 50 km/h. But from your perspective the train and the ball add their speeds together and the ball is going 150 km/h. For most moving objects in the universe you have to measure their speed from a particular frame of reference. That is, are we measuring the ball’s speed from your frame or from the person who is throwing the ball? We will get different answers depending on which frame we decide to measure from. But because light always goes at the maximum speed allowed by the universe, this does not happen for light. Let’s go back to the train car only this time the person on board has a flashlight. They’re traveling along again at 100 km/h. They turn on the flashlight. From their perspective the photons exiting the flashlight are going c (the speed of light, about 300,000 km/s). From your perspective the photons are traveling? Also c, exactly the same speed. Not c + 100 km/h.

Here’s the weird thing…at least weird from our day to day experience: the fact that light travels at the universal speed limit and its speed doesn’t change based on any frames of reference leads to time being experienced differently when travelling at different speeds. Let’s go back to the train car. This time, imagine there are mirrors inside the car and a beam of light bouncing between them. The light beam is bouncing straight back and forth and takes some very small amount of time to make one bounce. This is what it might look like, the back bars being the mirrors and the blue bar being the light beam:

Now, let’s set the train car moving. Now the light beam must bounce at a diagonal and travel a slightly longer distance in order to “catch up” with the moving car. Here’s what this looks like, again, the black bars are the mirrors, spaced out to show the movement of the train car:

Just like with the ball thrower, with most objects the train will just impart its speed on the object and we will see it go faster to keep up with the moving train across the slightly longer diagonals. But here’s where things get weird. Remember that light cannot go any faster and that it always goes at the speed c regardless of frame of reference (so its speed is the same if you are observing from outside the train or on the car). If the speed can’t increase it seems we may be stuck with a problem: the light has to travel a longer distance in the same amount of time but it simply can’t because the speed of light is conserved no matter what. Here’s the punchline: instead of adjusting the speed of light, the universe adjusts how much time passes for each frame of reference. From outside the train time on the train actually slows down so the light has enough time to get back and forth from mirror to mirror. From inside the train time appears to move at a normal rate. But from outside, time is moving slower.

This is the phenomenon known as time dilation. We don’t really start to see significant effects until we get pretty close to the speed of light but this happens every time you move with respect to someone/something else. Every time you get in a car, train, plane, skateboard, bicycle, heck even walking, time slows down for you just a little bit. So be wise, friends. Choose something productive to do with all your extra nanoseconds.

Some references:

Cox, Brian and Jeff Forshaw. Why Does E=MC²? Boston: Da Capo Press, 2009.

PBS Spacetime: https://www.youtube.com/watch?v=msVuCEs8Ydo

https://www.youtube.com/watch?v=Xo232kyTsO0

Khan Academy https://www.khanacademy.org/science/physics/special-relativity/lorentz-transformation/v/deriving-lorentz-transformation-part-2

What is a Chemical Element?

2018-03-17T13:59:00.003-07:00

Source: Wikimedia Commons

The periodic table of the elements organizes all the chemical elements. Elements are, in most ways, the fundamental building blocks of the kind of matter that we are most familiar with. You can go smaller than an element and find protons, neutrons, electrons and quarks (and possibly go smaller/more fundamental and find strings). You can go bigger as well and find molecules built of several elements. Most of the matter we interact with is made up of molecules containing multiple elements. But in order to have water or wood or a zebra you need atoms of various chemical elements.

While most of the stuff around us on Earth is made of compounds, often quite complex compounds when it comes to what makes up living things, we do have some experience with stuff made from single elements. This is known as a "natural state." Graphite, the stuff we use to make pencils write, is pure carbon arranged in layers that can easily slip off the tip of the pencil and onto the paper. Diamond is actually one giant carbon molecule. Oxygen, while we have a less tangible relationship with it, is perhaps the most important substance to us for, y'know, not dying.

We also have experience with some metals as single element substances. Aluminum is used to make foil and cans, silver has been used to make well...silverware and other household items, gold is used in jewelry and wires. While these metals are often found naturally occurring in a larger compounds we have figured out how to use chemistry to remove the atoms of just the metal. Natural state metals are extremely useful because they tend to be extremely malleable (you can mash them into a shape, like clay...though, this may require some pretty extreme heat) and conductive (these properties are why gold is so useful for wires).

Though it may be a bit indirect, we also may have some experience with neon in the form of neon lights or signs. We use several other gases that are chemically similar to neon to make these lights. When excited with electricity, these gases will produce different colors.

But these are all experiences of substances at a gross macro level. We can talk about malleability of metals or how neon glows when excited by electricity. The factor that makes an atom a given element, though, is the number of protons. You can change the number of neutrons (and get an isotope) or the number of electrons (and get an ion) but if you change the number of protons in an atom, you change the element. Thinking about how that translates to the macro level can seem...a little strange.

Take carbon again as an example. Right next to carbon on the periodic table is nitrogen which, among other things, makes up most of Earth's atmosphere. It seems, for lack of a better word, weird, that adding a proton to the nucleus of an atom would make carbon into a gas. But that exact thing happens all the time! Well, in geologic terms. All elements have what is called a "half-life." This is the time it takes for half of a given sample to undergo a transformation into another element. Energy is required to hold even many smaller atoms together and so they do not last forever. In the case of carbon, carbon 14 (which has 6 protons and 8 neutrons) "decays" over time and becomes nitrogen 14 (7 protons and 7 neutrons).

What we more commonly think of as "radioactive" substances are substances that do this much, much more quickly. Larger atoms like thorium, plutonium and uranium also tend to decay in a way that involves particles being shot out of their nucleus. It is these particles, along with the much faster rate (carbon 14 decays in about 6,000 years, the most stable isotope of thorium in just around 18 days) that makes these isotopes dangerous. But it also means they actually turn into other elements on the scale of human lives.

The alchemists' quest to turn lead into gold may not really have succeeded, but humans have found ways using particle accelerators to ram protons into atoms so fast that they stick, changing one element into another. While experimenters have succeeded in turning other elements, like bismuth, into gold, this is only at the level of about a thousand atoms in a given trial. This is about a billionth of a billionth of a gram of gold. So while it may not be what the alchemists were looking for, it does experimentally show that what we think of at the macro level as a fairly stable, concrete thing, is changeable and just comes down to the number of protons found in the nucleus.

So what is a chemical element? Like many things in the natural world, it depends on what scale you're asking. At the macro level gold is a shiny metal substance that's really good for making things like rings and wires and such. But at the atomic level it's just the number of protons in the nucleus. If you add a proton to gold it becomes mercury and, at least at room temperature, it melts.

Sources:

http://www.preservearticles.com/201012302013/carbon-14-deca.html

https://cosmosmagazine.com/chemistry/how-noble-gases-give-us-neon-lights

http://www.bbc.co.uk/schools/gcsebitesize/science/aqa_pre_2011/rocks/metalsrev1.shtml

http://www.bbc.co.uk/schools/gcsebitesize/science/add_gateway_pre_2011/chemical/nanochemistryrev1.shtml

https://www.livescience.com/23232-smallest-ingredients-universe-physics.html

https://www.youtube.com/watch?v=7g-WOMXe6Mo

https://www.scientificamerican.com/article/fact-or-fiction-lead-can-be-turned-into-gold/

I Don't Think This is a "Post-Truth World"

2017-11-04T07:54:00.000-07:00

I keep hearing about the challenges of science communication in a “post truth world” and I think that framing our challenges in this way plays into a false narrative. I think simply saying that we do live in a "post truth world" says that on some level we agree. I would actually wager that on average understanding of science is better now than it’s ever been. Sure science education in the US needs work. But it's not like we existed in some Eden where everyone understood statistics and uncertainty and p values and we’ve all been kicked out. The default truth telling devices for the vast majority of human history have been and still tend to be myths and metaphors (see what I did there with the Eden reference?). Yes, information moves faster, and misinformation is more readily available but propaganda has always been a tool of the powerful.

I think that we expect that whenever we're very close to certainty about any scientific finding then everyone should just automatically understand. I keep seeing references to the idea that people don't question gravity in the same way they do evolution. Exactly. Evolution questions belief systems that have existed for thousands of years. Science doesn't just get to come along and overturn all that in less than a hundred (I'm counting from the discovery of DNA, the real understanding of the mechanisms of evolution). Gravity is something we all experience every day. Evolution takes place over generations and isn't something most people actually get to see unfold.

I do agree that we need to get better at explaining uncertainty and statistics but we cannot come at this from the perspective that if we just explain these things in the best way then suddenly people will be able to understand the world from a scientific perspective. A lot of the phenomena we're trying to educate people about (climate change, again, evolution) take place over the course of more than one human life and tell stories that run counter to both people's lived experience and deeply held worldviews.

I think we owe ourselves the chance to revel in the fact that we live at a time where we have the best understanding of the natural world humans have ever had. We get to look across the universe with the best telescopes we've ever had. We get to peer inside cells and understand the mechanisms of mass. We freaking observed gravitational waves! This stuff is incredible! And yes, deeply challenging to communicate effectively about. But I think we ought to stop wringing our hands over a supposed "post truth world" and remember that humans have always been much better at talking in myth. And I am hopeful that we can collectively find ways to talk about statistics in a way that helps more people understand how they work.

A Response to "The Uninhabitable Earth" by David Wallace-Wells

2017-07-15T08:54:00.000-07:00

To start, I fundamentally agree with Mr. Wallace-Wells. Climate change is the largest environmental challenge humans have ever faced and we should be deeply concerned. It's important to keep in mind that we can make change, generally at the town, city or state level. We can manage our shared resources more responsibly through practical, step-by-step processes. Your neighborhood probably needs safer cycling and pedestrian infrastructure to help take gas-burning cars off roads. Your city needs more renewable energy and bigger batteries to generate electricity without fossil fuels. Your state, most likely, needs to reassess how it trades goods and gets food so we can reduce shipping distances and the carbon dioxide that comes with trucks traveling our highways. There are a multitude of ways of reducing the amount of carbon dioxide that goes into the atmosphere, which adds to the heat trapping blanket that gas creates. By talking to your friends and neighbors, and possibly more importantly, communicating with state and city civic leaders, we get closer to making those possible futures a reality. These kinds of changes are happening all over the country and the world, like in my city, Boston. We have become a safer biking city over the last several years and city leaders are currently legislating more renewables in our electrical mix.

OK, now that that's out of the way. You've probably read or at least heard about the article, The Uninhabitable Earth by David Wallace-Wells. It was published in the New York Magazine last week and since its publication has created a flurry of conversation online and in real life.

A lot of the response has been about how it's OK to talk about how scary climate change is. I think that's true, but I think the thing that everything I've read in the last few days misses is: it depends on a) who you're talking to and b) what your communication goal actually is. I think that, again, what I have in common with Mr. Wallace-Wells is that we both care deeply about this issue and want to see more change and at higher levels. I have had a lot of conversations about what can feel like a very grim future with colleagues. But my communication with the public is generally never about the impacts. It's about solutions. This is something the article never actually gets to, except at the very end leaving a vague notion that some scientists somewhere are maybe working on carbon capture or something. Oh, and Elon Musk wants to build a city on Mars. He doesn't empower you, the reader, to know what to do with all this fear you now have.

While I think we agree on some basic premises, there's a lot I disagree with about the article.

1. The premise that we're not afraid. Research shows that the majority of Americans are concerned about climate change and believe that climate change will harm Americans generally. The issue is that we believe others are not concerned and that climate change will not harm us directly. This is a communication issue not a matter of understanding that there is a huge problem that we all face.

Though a lot of the supporters of this article seem to have a very low opinion of social science, there also have been numerous studies done on how fear is generally an inhibitor to taking action, not the opposite. Here's just one paper and one article from the Guardian.

2. There's a premise that we (all Americans, let's say) need to understand the science better. If we just knew more about climate science and climate change, then we'd act. Again, the research doesn't support this and often shows the opposite. The more science you understand, the more polarized you become about acting on climate change. There are, again, a number of resources for this but I think one of the clearest is this video by Katherine Hayhoe. What the article says is that all the scientists talk about climate change in a way that is statistical and muted and we really need to envision what the world might be like and get freaked out. This also holds the premise that scientists are the best climate communicators. They can be, like Hayhoe. But they're not always.

3. More so in the responses, there has been a premise that when people are exposed to the more measured, hopeful kind of climate communication they're not going home and installing solar panels. That's true, but not the point. We should not be inflicting the solution on individuals for two reasons. One, individual actions do not fit the scale of this global problem. Two, this can lead to what's known as single action bias: where you buy a reusable water bottle and consider your environmental good deed done and then go back to living your life as is. We live in a system that runs on fossil fuels. It's the system that must change, not our behavior. At the beginning of this post I attempted to show what solutions look like. Communicating with each other and our civic leaders is currently leading to changes all over the country and the world. Solar panels at home are great but they are not the solution.

4. There is a premise that we haven't seen enough change in the last 30+ years of measured, hopeful climate communication so the whole project must have failed. However, it's only within the last several years that more concerted efforts to research, test and retest various ways of communicating about climate change have really taken off. There's Yale, of course, FrameWorks Institute and NNOCCI, Union of Concerned Scientists and others. Again, the cheerleaders of this article seem to have their minds made up about social science but I'm a firm believer in the scientific method, even when it comes to the very challenging world of human brains and groups of human brains. Another major reason that we haven't made more change is that the fossil fuel industry is incredibly powerful and it has taken time and concerted effort to find ways to build political capital to oppose them. It's still a work in progress.

5. The one premise that I do find somewhat intriguing to talk through is that we're missing the forest for the trees. That is, a fear based communication strategy may cause paralysis in an individual but that if this sentiment, that climate change is real and it's scary, gets accepted on a collective level then this is what will really shift the cultural zeitgeist and create the political will to make change. I don't want to get into the weeds on this one because I think it's a new argument and I don't have a good sense of its implications. But, I will reiterate that part of this challenge still lies in the fossil fuel industry itself, and that a million more scared citizens does not take their power away. I also think that a group of paralyzed citizens is still paralyzed.

I sincerely hope that those that are saying "this is good, people are talking" are right. I will concede that part of what we need to do is open lines of dialogue and actually get talking about this giant problem that, data show, we are mostly all pretty concerned about. I'm still not one bit convinced this is the right way to go about it.

Thanks for reading. I look forward to hearing from you if you have anything to debate or add in the comments.

Through the Pedantic Looking Glass

2017-03-23T14:23:00.000-07:00

I realize that since coming back to writing this blog basically all I've written about is the use of technical language and when and how to use it. There's two big reasons for that: one is that science and words are probably my two favorite things and right there at the nexus is the world of technical language. The other is that as a science educator science words are integral to my everyday work and I think about these ideas a lot.

As I have voiced in slightly different words before, as I got closer and closer to the looking glass of being pedantic I found myself falling through into a world where nothing quite makes sense and "technically correct" is no longer the best kind of correct. I'm writing about this again because of two examples that came up for me recently, both having to do, naturally, with cephalopods.

I have discussed many, many times the difference between "tentacle" and "arm" as it pertains to cephalopods. On a squid it's somewhat straightforward: tentacles are longer and have suction discs only on the clubs at the ends while arms are shorter and have suction discs all the way down. However there are some problems with this. First when you look outside the cephalopods this distinction no longer makes any sense. Snails, polychaete worms, star-nosed moles all have tentacles. They are often chemosensory but not always, they are often used for grabbing or holding food but not always. Generally the only other appendage that gets called an "arm" are human arms. So these are not definitions (which in science, technical words are generally thought to have definitions) but rather conventions. That is, it is convention to call a cephalopod appendage with suction discs only on the club at the end a tentacle but this is not the definition of the word "tentacle."

The other real problem with arm vs. tentacle within the cephalopods is that the nautilidae have "tentacles" but lack suction discs entirely. So again, these terms, both "arm" and "tentacle" appear to be conventions and not definitions. That's fine, we use language in this way in colloquial life all the time. It generally leads to only minor confusion. The thing is that in science, we have tricked ourselves into believing that the words we use always have a very precise meaning. The truth is, this is only sometimes true. Planet, continent, species are all examples of very common terms that really lack a precise definition. But there's fun to be had here. The natural world is tenaciously difficult to put into the boxes our human brains want to put it in. The fun is figuring out what other sorts of containers we can use. Turns out these imperfect conventions are fairly useful.

The other example around technical language that came up recently was around the word "octopi." In a lot of the scientific community this is regarded as an "incorrect" plural of "octopus." This is because the word "octopus"is a Greek route word and not a Latin route word and the -us to -i pluralization is not used in Greek. So the "technically" correct pluralization of "octopus" is "octopuses." But here's the rub: a lot of people use the word "octopi."

And this is the argument that I think we all, myself included, need to do better at remembering: if people use a word and you understand it, it probably means it's a word. If we only obey the "dictionary definitions" of words or the "technical" definitions of words we're saying that a whole section of language is completely off limits: slang. Even though it might not be "good grammar" you know perfectly well what I mean when I use the words "a'int," "dope," "cool" (I don't mean temperature), etc.

This might be where we all fall into the looking glass of pedantry and "technically" correct: I'll introduce the character of the Merriam-Webster dictionary. They include "octopi" among their plurals for "octopus." So does this mean that "if the dictionary says it's a word, it's a word"? Kind of. Dictionaries change, words change, usage change and with this example that's the real point. A lot of us think about the dictionary as being some kind of Platonic codification of our language. Sorry, though, language refuses to play that game. So if you understand when someone says "octopi" that they mean "more than one octopus" why correct them?

These rules morph and flex depending on your audience. Should I use "octopuses" when I'm addressing marine biologists and "octopi" if my eight year old student has just used that word and not "octopuses?" Yeah probably yes to both of those.

As I was developing this post I came across this graph on Twitter and thought about not even writing this post at all. As you can see, I did write the post but I wanted to include it here, because, well, I still think it sums up what I just said a bit better than I said it.

click to embiggen. Courtesy @robdrummond

As usual I'll invite you to disagree, yell, berate and complain in the comments.

The Word "Worm"

2016-11-17T06:31:00.001-08:00

It's no secret that I think common names are a problem. They would be great if they were as systematized as scientific names but that's simply not the way language works. Common names are a product of colloquial, everyday speak and therefore they are the antithesis of scientific names. They lead to situations where we have a blue crab, a lesser blue crab, a red blue crab (seriously!?) and an ornate blue crab all inside the same genus. Common names give us such taxonomically frustrating linguistics as the electric eel (a knifefish more closely related to catfish than eels), the bearcat (something like a civet), and the flying lemur (in a branch of mammals separate from all the primates).

It also creates situations like when I get a video of some insects milling around on top of a tidal pool from a friend, she asks what they are, and I reply "Anurida maritima," and there is no common name. The fact that we typically understand organisms only through their common names means that when we're faced with a situation when an organism doesn't have a common name we don't have the hooks to hang new information on much of the time. I'm not suggesting we give up on common names, again, they are part of colloquial language and you cannot stop the indomitable force that is the evolution of language. But there's one name that's always deeply frustrated me: "worm."

If you use the word "worm," people typically think of an earth worm, which is a land-living oligochaete in the phylum annelid, one of the closest living families to the arthropods. But when you bust out a list (I got on this rant when I was once in a middle school science room and saw a poster of major animal phyla) of all animal phyla you start to see how little this name means: spiny headed worms, Acoelomorpha, segmented worms (Annelid), arrow worms, goblet worms, gastrotrichs ("worm-like"), jaw worms, acorn worms and roundworms, horsehair worms, ribbon worms, flatworms, peanut worms strange worms, velvet worms. The number varies from source to source and also starts to get even more garbled when you descend to the subphylum and lower levels.

So what, then, is a worm? Etymologically speaking the word comes form the Latin "vermis:" vermin. This is a great colloquial word with no real scientific meaning. It's kind of like...anything gross or small so flies, maggots, earth worms, but even rats and snakes can be vermin. Moving forward into Middle English you get "wyrm" which means a snake or a worm (and as I hope you all know, a snake is not a worm). When you start poking around in other languages "wyrm" sometimes means "dragon" as well.

So biologically what is a worm? Well, the online OED says that a "worm" is "Any of a number of creeping or burrowing invertebrate animals with long, slender soft bodies and no limbs." That is basically it, except for Onycophora, which does have limbs. But we get to call anything that is bilaterally symmetrical and longer than wide a "worm." Which is, as we've seen, a huge chunk of the animal world.

So I'm not suggesting we get rid of the word. But next time you call something a "worm," maybe remember how unspecific the word really is.

http://www.sms.si.edu/irlspec/NamSpecies.htm

http://mentalfloss.com/article/60587/15-animals-misleading-names

http://eol.org/collections/18879

https://en.wiktionary.org/wiki/worm#Etymology

https://en.wiktionary.org/wiki/vermis#Latin

https://en.oxforddictionaries.com/definition/worm

How We're Related to Other Four Legged Vertebrates

2016-09-30T13:47:00.002-07:00

I'm doing battle with common misconceptions in biology, a lot of which we were all taught in school and people still being taught in school. I'm not exactly sure the level of importance of this one but I think I can handle it fairly quickly. As always, please correct any misconceptions or feel free to argue with me in the comments.

There is a common misconception, or rather a set of misconceptions, around the relationship of the groups in Tetropoda. Tetropoda, or the tetropods, are amphibians, mammals, reptiles (really non-avian reptiles) and birds (which are reptiles, technically). These are the major groups that are still around today. When you look at a lot of cladograms for these groups they look something like this:

image by me, click to embiggen

What the cladogram actually looks like is something more like this:

image by me, click to embiggen

This is a minor difference, but it's an important one and there are several misconceptions that are portrayed by the first one. First, and I've glibly added an explosion to humans at the crown in the first one to reinforce this, it portrays evolutionary time as always going from "less advanced" to "more advanced" with us humans at the very peak of...advanced-ness. Evolution is not a movement towards more advanced. Natural selection doesn't have any conceptions about what is more or less advanced, only what organisms are best at getting their genes to keep going. Just check out the bacteria. They're the polar opposite of what most would probably call "advanced" but they're darn good at making their genes survive for billions of years (and yes, a Domain is very different from these much smaller clades).

Second, and I may be projecting here, but I think this also portrays the misconception that amphibians "evolved into" reptiles and then reptiles "evolved into" mammals. But if that were true, wouldn't there only be mammals? If reptiles evolved into mammals, why are there still reptiles?

Partly because mammals did not evolve from reptiles, rather the two groups share a common ancestor. Millions of years ago there was a population of animals that weren't mammals or reptiles. As this population evolved it diverged into (at least) two distinct groups. One is what we today call mammals and the other is what we call reptiles and birds. You'll sometimes hear people use the term "mammal-like reptiles." There's no such thing. There are animals that came before the common ancestor of reptiles and mammals which are neither and there are animals after that common ancestor which are one or the other (sort of, this is a bit of a simplification). There's a group of animals called Synapsids, which mammals are a part of, and early Synapsids didn't really look or behave much like modern mammals and maybe they were kind of reptile-ish (in that they were tetropods that weren't amphibians) so we've gotten stuck in the habit of calling those animals "mammal-like reptiles" even though they're really a lot more mammal than reptile.

Third, this also may portray the misconception that reptiles have been around longer than mammals. So again, it gets a bit complicated, but the two lineages that have led to what we currently call "mammals" and "reptiles" have actually existed for exactly the same amount of time. That's because they share a common ancestor, they diverged from the same population of animals millions of years ago. So what we might recognize as a "modern mammal" didn't appear until much later, these two clades have existed alongside one another since they both evolved from a common population.

Let me know what I got wrong, what's confusing and what you're disagree with. This was actually a bit harder to write than I thought and I hope that my simplifications make this understandable and fairly accurate.

Invasives

2016-09-23T13:27:00.000-07:00

I recently finished the book Unseen City by Nathanael Johnson and rather than write a formal review (the upshot is that if you're knowledgeable about natural history, especially urban natural history you likely won't learn a ton but it's a good read, I would recommend it) I wanted to address a specific few sentences in the book about invasive species. Johnson writes: "Immigrant species often do reduce native populations, sometimes significantly. But the ecologist Mark Davis has pointed out that they rarely cause extinctions, and when they do it's of populations in isolated habitats like lakes or islands. All this mixing may yield more biodiversity by producing more combinations, hybridization, and new species." And in the book's conclusion: "These invasive species are not nature's destroyers, but rather its creators. They begin setting up food webs, they evolve and diverge into new species."

While it's true that you can find examples, as Johnson sites, of stories where invasions are followed by an increased biodiversity I found it odd that he brings up this incredibly complex issue but only writes a little more than two sentences about it. One of the big issues here is that we don't all agree on what an invasive species actually is. I'll illustrate with three marine invertebrates that have been introduced to New England through human activity.

One: Hemigrapsus sanguineus, the asian shore crab. Introduced in 1988, this crab is considered a significant concern to local ecosystems primarily due to its voracious feeding. This has two major impacts, one, it can easily out-compete local species like Cancer irroratus and borealis, two, it specifically has been correlated with a decline in juvenile lobsters (presumably it eats the post-larvals).

Two: Carcinus maenas, the green crab. Introduced in the early 1800s this larger crab species purportedly has an "insatiable" appetite and, unfortunately for us, seems to like many of the same animals we like such as clams and mussels. It's also theorized that it may be contributing to salt marsh decline. Which, I will point out right now, we think is bad. I could ramble all day about salt marshes but the two highlights are that they are more productive than rain forests and sequester more CO2 than rain forests (which is why we should have been learning about them growing up in the 80s).

Three: Littorina littorea, the common periwinkle. We have no idea when the common peri got to New England, and it could have been as long ago as circa 1000 AD when Vikings first came to North America.

Here's the rub: almost no one considers L. littorea an invasive. Indeed, a NY Times article describing the research of Prof. Mark Bertness who has done some of the most robust work on the impact of periwinkles on New England coasts as far as I can tell, describes them as a keystone species. You might call that the opposite of invasive.

And yet, when you put the present day ecological data on how periwinkles feed together with historic maps that show where there used to be salt marsh it seems very likely that periwinkles ate through a huge amount of algae and reduced much of that historic marsh to rocky shore. And remember, we agreed above that salt marshes are good.

What's the difference between these three species? Time. There are a couple ways an invasive can be defined as such. It's always non-native but to be invasive it's generally agreed that it has to have some negative impact on ecosystems and/or the economy. For H. sanguineus and C. maenas it's easy to check those boxes but as soon as you look at the whole story for L. littorea you are forced to check the same boxes. Struggling to define invasive (vs non-native, and why we don't call periwinkles invasive) I've often said "well, no one is suggesting any kind of management for periwinkles." But no one is suggesting that for the others either. At least when it comes to marine inverts, the plan is monitoring, education and the hopeful prevention of new invasives but there is no plan to manage the established invaders. And while there are management plans in place for invasive terrestrial plants they will likely need to continue indefinitely. So as far as I can tell, really the only difference is that periwinkles have been around for about a thousand years and no one remembers a New England ecology without them. Heck, they might even be a keystone species!

So the weird thing is that when it comes down to it I do agree with Johnson that we shouldn't be losing our hair over invasives. They are, in a lot of ways, just another example of the biological world moving and evolving and changing. However, I'm hesitant to say, with such simplicity, that invasives (writ large) generate biodiversity. Sure, you can find examples of that happening, but you can also find examples of invasives out-competing local species, close to extinction or completely altering huge swaths of ecosystems (and again, I'm going to make a value claim that salt marsh is more important than rocky shore, we can debate that in the comments if you like).

Through writing this I've been thinking about another book: Out of Eden by Alan Burdick. In this book he doesn't so much argue that invasives are a good thing but that, well, there's not a heck of a lot we can do about them so...why freak out? Again, I think that's where I land. That's also a whole book, not a few sentences in a book that's not really about this complex and often really interesting issue. They might be a problem but our relationship with invasive species is a huge part of the story of how we humans are forever changing the biosphere. Maybe it's not great, I'm still not sure how to make a value claim about such a big, complex issue, but there's some really neat science going on there.

Also, kudzu stinks.

Sources:

Johnson, Nathanael. (2016). Unseen City. New York, NY: Rodale Inc.

http://www.seagrant.umaine.edu/research/projects/dv/green-crab-marsh-impacts

http://www.rimeis.org/species/hemigrapsus.html

http://nas.er.usgs.gov/queries/factsheet.aspx?SpeciesID=190

http://www.nytimes.com/1988/08/23/science/tiny-snail-is-credited-as-a-force-shaping-the-coast.html?pagewanted=all

http://invasions.si.edu/nemesis/CH-IMP.jsp?Species_name=Littorina+littorea

http://bertnesslab.com/docs/labpublications/Bromberg%20and%20Bertness%202005.pdf

Meleagris gallopavo [Turkeys] at Mt. Auburn Cemetery

2016-09-23T12:01:00.002-07:00

No Such Thing as a Protist

2016-09-08T18:44:00.000-07:00

So I care about cladistics, which is a way of classifying living things based on traits that are inherited from a common ancestor. I might care about cladistics too much. I've been trying for a while to understand why I care so much. I think that it's because without an understanding of evolution and cladistics you're not really understanding the biological world. I think the fact that birds are theropod dinosaurs just makes them a whole lot cooler and the fact that octopuses' closest relatives outside the other cephalopods are clams and snails is simply amazing.

I've also been after a life goal of not being such a pedant. Sometimes my desire to revel in the true nature of a living thing comes into conflict with this. (Like when I refer birds as "reptiles" without missing a beat and not really explaining myself.) But I think that's where I've actually found the most fascinating discoveries. There are moments when our words for the natural world start to break down because...well hundreds of years ago some people who really didn't understand evolution or cladistics came up with them and they don't actually work all that well a lot of the time.

So while I really am trying to be less of a pedant: I have a real problem with Kingdoms. Specifically Protista. I'll show you why...protists don't exist. Here's how you probably learned about the tree of life:

Maulucioni y Doridí CC BY-SA 3.0

Here's a (probably fairly up to date) image of the actual tree of life, simplified to mainly show the eukaryotes which are living things that are like us...that is their cells are quite a bit bigger than a bacteria or archaea and their cells have a nucleus:

Vojtech.dostal CC BY.0-SA 3 click to embiggen

See the kingdoms? Yeah you've got Bacteria and Archaea down at the bottom. Fungi's right there just above bacteria inside opisthokonta. Metazoa, that's animals, inside the same group as fungi. Plants are also pretty obvious, inside archaeplastida next to green algae. So...the $64K question: where is protista?

click to embiggen modification of the above illustration CC BY 4.0

See it was confusing because IT'S EVERYTHING IN EUKARYOTA THAT'S NOT IN ONE OF THE OTHER KINGDOMS!!

OK I'm calm...I've been trying to reflect and figure out exactly why this bothers me so much. I think I've got a decent analogy. It has to do with monophyly which is when you group organisms into what are called clades (clades, cladistics same root word) which contain a set of living things and all common ancestors. This is basically the idea that "kinds" of living things are ones that evolved from one another, you don't combine things that don't have a direct evolutionary relationship, you only combine things that are descendants. So if you go back and look at the tree above it seems very obvious to me that there are six groups of eukaryotes plus bacteria and archaea. You can call fungi a "kingdom" if you want but that means you also have to call malawimonas a kingdom...and well all of these things.

So here's my analogy using a subset of the so called "protists" for my comparison. Here are algae:

click to embiggen modification of the above illustration CC BY 4.0

(well actually there's things we call algae in several other groups in Eukaryota and also we sometimes call cyanobacteria [which if you couldn't tell from the name...is a type of bacteria] algae but whatever, I'm just going with full clades of things we call algae for now). We call these things algae, from what I understand (and full disclosure here, I am not a taxonomist, I am a science educator and I could have this wrong) because they are photosynthetic and they are not plants. And also from my understanding, and I believe this is the rub here, photosynthesis appearing in at least many of these different groups is due to convergence, that is it has evolved multiple times. So the different groups having photosynthesis is not because they are the "same thing" but because photosynthesis is useful and has evolved several times.

Here's my analogy: this is a (very, very) simplified cladogram of things with powered flight:

by me CC BY 4.0

As we all know, bats, insects and birds all have powered flight. So, we could call all of them the same thing. We could have a word like "flappydoo" to describe all of these things.

Flappydoo are algae. Algae are called that simply because they are tiny things most humans don't really understand that can photosynthesize. Flappydoo are slightly bigger things that most humans reasonably understand that have powered flight. I'm just lumping things in a pretty big clade (animalia) together due to a trait they evolved because its useful. But that trait is convergent.

I was talking about a similar thing just today and I think I reached another level of understanding of when I'm supposed to be pedantic and when it doesn't matter. In my work I spend some amount of cognitive energy telling people that horseshoe crabs aren't crabs (they're related to spiders) and that starfish aren't fish (right, they're inverts in echinodermata) but *technically* hermit crabs are not "true crabs," that is they are in a different clade in a very closely related group. But I don't think that matters. Not one bit. I also don't think it matters if someone calls a lobster a crab. Why? Convergence. Most of decopoda, the group that contains lobsters, crabs, squat lobsters, shrimp, mantis shrimp, etc. probably had ten legs and probably some of those legs had claws. That describes a crab and a lobster and a hermit crab. They're the same thing. Probably none of those traits evolved convergently.

I brought up falcons during my discussion today because they are not hawks and again convergence was the important thing. It was agreed that it's important to distinguish hawks and falcons because they're convergent and ultimately, that's cool. That's interesting. The fact that hermit crabs and "true" crabs are not *technically* the same clade isn't interesting.[actually it is but I think for most people this is a level of detail that's over the line of pedantic]. They didn't really (probably) evolve anything really interesting through convergence.

I think there's a lot of grey area here, clearly. But my main goals are two: I hope that you care a little less about what things are called and spend more energy thinking about what is interesting about a particular group of living things. Two? I do hope you stop using the term "protist" and you stop using kingdoms and start only using domains if you haven't yet. I think it's really silly that students in most schools are still learning about kingdoms.

Then again I learned about the Bohr model of the atom in school. Waste of time...

Insect

2012-10-20T12:39:00.000-07:00

This image is pretty zoomed in from the original so it's not the best quality but this shot actually came out reasonably well. I know it's an insect...but that's it.

Hericium americanum

2012-10-06T11:25:00.000-07:00

I found this specimen during my last trip to the White Mountains in NH. This species has several common names including the pom-pom mushroom, lion's mane mushroom, bear's head mushroom, monkey head mushroom and icicle mushroom. Perhaps many more. This is a great refresher on why we need binomial scientific names.

Apparently this species and the rest of its genus are edible and commonly eaten in Asia, especially China and Japan. As with any mushroom you need to be 100% certain you are collecting the correct species. With many species of fungus there are species that look similar or almost identical that are toxic. Recipes suggest this mushroom as a replacement for rice in soups but that it is best fresh. It seems it is very easily cultivated, however.

Generally grows on decomposing logs, as pictured above.

Sources:

http://db2.photoresearchers.com/preview/14365556/BU7829.html

http://botit.botany.wisc.edu/toms_fungi/jan2003.html

http://americanmushrooms.com/edibles2.htm

http://en.wikipedia.org/wiki/Hericium

Tarn

2012-09-21T06:51:00.001-07:00

I'm still here! OK so I've been insanely busy for the last few months with work and planning my wedding but now that I'm all married hopefully I can get back to posting. I know...I say things...anyway, this time the post is about...GEOLOGY!

I'm not very good at geology so I invite you to berate me for inaccuracies in the comments. The image above I made during my last trip to the White Mountains in New Hampshire. This is a body of water called a tarn near Mt. Lafayette. A tarn is essentially a mountain lake. The basin of the lake is formed by a glacier and is always found on one side of a mountain slope. You can see said slope above the tarn in this image.

Often a terminal moraine provides a dam that keeps water in the basin. What's a terminal moraine you ask? Well that's one bit of geology I actually am fairly confident I understand. So when a glacier slides across the landscape (glaciers are so huge, by the way and I've never actually seen one in real life...I have to imagine an ice sheet of this size) it picks up a lot detritus including rocks and boulders. Here in New England if you've ever spied a huge boulder just sitting all by its lonesome in a field with no other boulders around you can be pretty sure a glacier dropped it there. So anyway, the glacier will pick up rocks and boulders and also drop them. A moraine is a collection of detritus, soil, rocks, boulders, etc., dropped by a glacier. A terminal moraine is a moraine formed at the furthest advancing edge of the glacier. Usually the largest accumulation of debris is at the "snout" of the glacier (the advancing face/edge) and as the glacier finally stops and begins to melt it leaves a (sometimes) massive pile of rocks and such.

So it's this kind of moraine that provides the dam for a tarn. Now you can impress your friends by telling them about tarns and moraines. Fun geology words!

OK I have a few other photos from the Whites I'm hoping to post. Get ready for FUNGUS!

Farmer Ants

2012-06-22T06:50:00.002-07:00

So this is why I love ecology. Just looking at one organism at a time is often super interesting stuff...I mean have you seen a horseshoe crab??? But often the combinations of organisms that have evolved side by side over millions of years is just downright mind-boggling.

I already was a big fan of ants. I always find it really interesting to watch them and think about how much of their sensory world involves chemicals, many of which are produced by other members of their species. Ants leave chemical footprints and generally have a few different chemicals that can mean different things. Their antennae are incredibly acute chemical sensors, able to pick up very small amounts of molecule.

I also knew that ants sometimes farm aphids but after shooting this process the other day I found that these two facts are connected. I was unable to access the original article here from science daily but I managed to find a quotation of it here.

Scientists have just recently learned that ants that farm aphids, like the ones below, use a chemical produced by their legs to sedate the aphids they are farming. Ants will often bite the wings off aphids to keep them from flying away and now we know they're also drugging them. This seems cruel, from a human perspective, but keep in mind that the generally much larger and more capable ants are also defending the aphids from dangerous predators like ladybugs and other beetles. It's actually rather like our relationship with livestock. We mess with their genes and keep them corralled but we also protect them from wolves and mountain lions.

These ant colonies keep aphids because aphids produce a sweet liquid known as honeydew as waste when they feed on certain plants. And the ants...well they consume the aphid waste. Yum!

The methodology used to discover this is elegantly simple and ingenious. They had ants walk on a surface and then placed aphids on both a surface that had and had not been walked on by the ants and watched and recorded speeds and such. They found that surfaces that had been walked on by ants caused the aphids to slow down markedly. Especially interesting was when they used a dead leaf as a surface. Aphids should avoid dead leaves at all costs, it's going to make you more obvious to predators and there's no food there for you. But when they had dead leaves walked on by ants the aphids kind of moseyed off. Really cool science, I think.

Oh and here are the images. The little gray blobs are aphids...easier to see in the web album.

Two Images of Beetles

2012-06-16T13:43:00.000-07:00

Because I'm busy and kinda lazy but I took these decent shots today. I've got some other new images but I also need to research and write for them so...beetles. Enjoy.

Convergence and Confusion

2012-06-01T08:23:00.001-07:00

I went to the Stone Zoo yesterday and had a great time checking out some interesting animals. They have a really nice collection, skipping a lot of the usual more showy African animals but including a few black bears, a lynx and a set of Tibetan steppe animals and South American animals. They generally seemed healthy and active which is always good to see. The highlight of the day, by far, was their bird show. Mostly the birds were raptors including a very nice looking bald eagle that I was able to get very close to at the end of the show. Which...y'know is really cool to see such a big bird that close.

But maybe the coolest bird was their red-legged seriema. This unusual bird hardly ever flies but rather runs or walks and has a very interesting hunting behavior. They will grab small animals, usually reptiles, by the tail and then smash them into the ground. You can find an image of this here. I wanted to learn a little more about this bird, and couldn't quite remember the name after getting home from the zoo so I consulted a large bird book I've got. I immediately assumed it was a crane relative due to its long legs and found it there with the other cranes. Apparently I have an eye for sorting birds into families.

Except really I don't. This is the really interesting thing about living in a time that we have access to molecular data in regards to phylogeny. For hundreds, really thousands, of years scientists and natural historians have been sorting animals based on how they look. It makes sense, of course, that animals that look very similar should be closely related. And much of the time this is correct. All insects with a set of wings and a set of hard, protective wing coverings are all coleoptera, everything with a soft, shell-secreting body is a mollusk. However we forget that birds are tiny subgroup of an already small subphylum and so when you get that specific weird things begin to happen.

Over the course of talking about several of the animals we saw I found myself examining a mammal and bird phylogeny really closely. I'll talk about the bird phylogeny but you can check out the mammal one here. So a few things to notice on the bird phylogeny here. (If you're not familiar with how to read cladograms, basically each fork represents a common ancestor and the lengths of the lines represent time so the longer the line, the longer that group has existed and the closer one group is to the fork of another, the more closely they are related). So first find the seriemas. They are actually not cranes at all. They are what we call a sister group (i.e. the group on the other side of a fork) with a group containing parrots, falcons and the group called passerines, which are all perching birds (basically all yard birds...mainly small birds with gripping, perching feet). Something else to point out here, falcons are not the same thing as hawks or owls, each of these three bird families are spread fairly far out on the tree. The falcons being placed with parrots and passerines is something very new, I found an article from Tetrapod Zoology written just last month describing the new molecular data and the reorganization of the clades.

The fact that falcons look just like small hawks and owls really resemble hawks, at least in terms of beak shape and talon shape, is what we call "convergence." When organisms fall into a similar niche in the ecology (i.e. they are getting their food and living their lives in similar ways) more often than not then evolve to look very similar. It makes sense. If you have two families of birds that are hunting other vertebrates they are both going to want to be fast and they are going to want to have very sharp beaks and talons. And that's exactly what you find. Even though hawks and falcons are NOT sister groups they look the same because they have both evolved to utilize other vertebrates as energy sources.

So I've rambled pretty long about phylogeny here (it's probably my most nerdy passion) but a few more really interesting things to point out on the bird tree. Herons, storks and cranes...all different things. More convergence. And the most surprising thing (to me)? Find loons, grebes, and ducks. All different things. A grebe's most close relative is a flamingo! Ducks are also found all the way across the phylogeny from most other shore birds, found in blue. They are actually most closely related to things like pheasants and quails.

One final note. I'm now a huge fan of the seriema. I think they're really cool, very dinosaur-like birds. One thing I found in my research: scientists now believe their closest relatives where the terror birds. Which, if you're not familiar with, you should be. You can start here.

OK, I'm finally done ranting about convergence. Enjoy learning about terror birds!

Branta bernicla

2012-05-12T07:40:00.002-07:00

Most of us are familiar with the ubiquitous Canada goose but this is another species we find in New England for at least part of the year. The Brant's (or Brent) goose is, like most New England avian reptiles, migratory between the Arctic where it summers and breeds and the North American coast. During its stay here it inhabits inter-tidal regions of either sandy shore or marsh flats. This bird is not entirely marine, however, and spends its summers in the tundra or on grassy islands where its diet consists primarily of lichen and terrestrial plants.

The Brant's goose is primarily herbivorous but will take some animal food as well especially eggs but also worms, snails and amphipods. (What are amphipods? The next time you're at the beach find the wrack-line, the line of seaweeds and marine detritus left at the high-tide line, and turn some of it over. You'll likely see little pale crustaceans start crawling and flipping themselves around. Those are amphipods.) Because breeding takes place near freshwater the young Brant's also will feed on insects and aquatic inverts.

There are several subspecies with varying color patterns across the range of the Brant's goose. As a species it is considered an IUCN species of least concern.

As usual, I reference eol.org.

Vulpes vulpes

2012-04-29T10:10:00.000-07:00

I've been marveling lately on an illustration I saw recently of an extinct species of crocodile lunging out of the water, reaching to grab a Tyrannosaurus Rex. The event itself, that it occurred on the planet we now inhabit, is a marvel in itself but what I've really been marveling at is the sheer amount of energy involved in that event and how systems involving that much energy all begin their story in the form of single cells (both evolutionary and developmentally speaking). From just two little cells comes a massive, 30 or 40 foot crocodile death-rolling a T. Rex. Just so cool.

The day I took the photos below I witnessed what may have been the most wild biological energy I've seen. The event was too far away from me so I don't have any photographs but here's what I saw: at first we noticed a group of gannets plunge diving. You can see the group of birds circling around, looking a bit like gulls and then one will just drop out of the air and slash into the surface. One after another was diving over and over. That's already a lot of energy but you have to imagine the enormous school of fish that was hidden below the surface as well.

After a few minutes we walked a little further and noticed a second and third large group of gannets plunge diving. Now I had the thought..."there's an awful lot of fish under there. I wonder if there are whales nearby." Sure enough, we waited and began to saw fin slapping, a behavior humpbacks and some other whales will do to signal good fishing spots to their kin. You see the huge pectoral fin (humpbacks, even though not the largest whales, have the longest pectoral fins) rise up from the surface and then come crashing down, making a noise loud enough to hear from shore.

After watching all this energy, all these cells consume one another for a while we then noticed that there were more cells around. I did get photographs of these and so they're the title of the post. Here is Vulpes vulpes, the red fox:

By being quiet we were able to watch these two cubs rough and tumble play for a good 10-20 minutes. It was really quite cool and a fairly unique experience for me. I've seen foxes in the wild before but never out in total daylight playing like this.

So V. vulpes here is the world's most widely distributed wild carnivore. And though they mainly feed on small rodents like mice and voles they will eat just about anything they can get: other mammals, small birds, inverts like beetles and worms, decaying fruit and bits from compost piles are all on the menu. I've even seen foxes "fishing" (for what I'm not entirely sure).

Unlike wolves foxes do not form packs but do live in smaller social groups usually consisting of a mated pair and a few of their daughters who will help to raise subsequent pups. Like all canids and most mammals they mark their territory with urine.

V. vulpes's territory is limited by C. lupis (the grey wolf) and C. latrans (the coyote) however reduction of the former's range has increased the range of v. vulpes. The red fox is also capable of inhabiting nearly any temperate terrestrial biome from coastal scrub/dunes (as pictured above) to alpine ridges.

V. vulpes also includes a vast number of subspecies/subpopulations that vary in coloration. If you see a fox in the United States that is NOT the typical reddish orange of the animals depicted above it is still, in all likelihood a red fox. Though this exchange did not involve as much energy as a T. Rex or a whale I was still glad I had the opportunity to photograph these beautiful animals and looked forward to sharing them here. I have a few more that I may just post to the web album. Enjoy!

One note: I have been failing to include references for the last few posts on L. littorea and Uca genus crabs. Those along with this post have nearly entirely been based on information from eol.org. As always this is my go-to reference. The post on L. littorea also came from my knowledge as a marine educator....yeah, I talk about snails a lot.

Natural History Reading: Four Fish

2012-04-29T08:02:00.001-07:00

So as I mentioned recently in my post about dolphin strandings I am finally beginning to see myself as not just a science educator but also a marine educator. I've worked for a public aquarium for a little over two years now but until very recently I still strictly referred to myself as a "science educator." The distinction is that my background is in neuroscience and my teeth cutting experience in the field of informal ed. happened a children's museum where I mostly designed experiences related to they physical sciences and my main interests related to animals are still evolution, classification and the more nerdy, "sciency" topics rather than what I would consider "marine" topics. However working at a public aquarium for two years can influence your thoughts and perspective and teaching and even though I still hold the belief that the most important way we as educators encourage stewardship, especially with young children, is by scaffolding appreciation and excitement about nature, I am coming to include the "marine" part of my work more and more into my self identity.

So why is this important? Why the preamble? Because the book I'm reading right now, Four Fish by Paul Greenberg, I think does a great job of showing how much fascinating natural history there is behind a modern marine stewardship problem like over-fishing. The book is ostensibly about our (our meaning humanity) relationship with four fish, (hence the title) salmon, bass, cod and tuna. It tells the historical story of their fisheries and why these four fish have become modern staples. It deals with the idea of fishing being the last "wild" resource that humans consume and where we seem to be going and where, perhaps, we ought to be going (baramundi farming, spoiler alert!).

But the most interesting part of the book, for me, is the natural history (I know, huge surprise). Greenberg writes eloquently on how the natural histories and life histories of these particular animals forged our relationships with them and are often counter to how we attempt to continue our modern relationships. He also relates this concept to fishes he believes are indeed more suited to our continued consumption.

Overall this book is a great read and one of the reasons I'm enjoying it so thoroughly is that I see his writing as a bit of professional development, helping me remember that because I'm a marine educator I don't need to stop being a science educator. His ability to present current policy and environmental issues through their natural history is quite inspiring and completely enjoyable. If you eat fish, keep aquaria, love fishing or have any strong emotional ties with fish (read: if you are from New England) I highly recommend this book.