Online Study

Mitosis(MITOTIC CELL DIVISION)

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MITOTIC CELL DIVISION

ALL CELLS ARISE FROM OTHER CELLS BY CELL DIVISION. THIS PROCESS INVOLVES BOTH:

1) MITOSIS (duplication of the nucleus)

* this is an orderly series of complex changes in the nucleus
* this involves an EXACT DUPLICATION of the complete set of chromosomes
* also makes sure that these chromosomes are separated into two equal sets
* forms 2 cells identical to the first

2) CYTOPLASMIC DIVISION (cytokinesis)

* when the cytoplasm of the parent cell divides into 2 daughter cells
* also called cytokinesis

***When the process of cell division is uncontrolled, cells keep reproducing... which is called CANCER***

* Mitosis happens in all cells in humans EXCEPT eggs and sperm

CELL DIVISION

the process by which the nucleus of a cell divides, producing two nuclei with the diploid (2n--2 sets of chromosomes) number of chromosomes

I. INTERPHASE

* in between actual divisions
* the cell grows
* DNA exists as chromatin (a messy plate of spaghetti)
* the DNA duplicates (replicates) so now there are briefly 4 sets (4n); normally there are just 2 (2n)--one from each parent
* the centrioles also replicate (duplicate)

II. PROPHASE

* the DNA starts to condense and form chromosomes--the two halves of the chromosome (each chromatid) are held together at the centromere

* the nuclear membrane that keeps the DNA (now in the form of chromosomes) in the nucleus starts to disappear
* the centrioles start to move towards different ends (or poles) of the cell
* the spindle apparatus (looks like a cage) forms from the framework of the cell around the centrioles (which now are look like stars called 'asters')

III. METAPHASE

* the spindle apparatus is fully formed and the chromosomes attach to it at the centromere
* the chromosomes line up in the middle of the spindle (called the metaphase plate)

IV. ANAPHASE

* the chromosomes separate at the centromere and split apart (chromosomes move away from each other)
* the spindle fibers shorten and pull the chromosomes to each end (aster)

V. TELOPHASE

* the chromosomes have finished moving to the different poles (ends) of the cell
* a new nuclear membrane starts to form around each new COMPLETE set of chromosomes
* the DNA starts to uncoil again to form chromatin

AT THIS POINT, ONLY THE NUCLEUS HAS DIVIDED INTO 2 IDENTICAL NUCLEI...WE STILL HAVE ONLY 1 CELL!

VI. CYTOPLASMIC DIVISION

* after the reformation of the nuclear membrane, the cytoplasm divides
* this make 2 daughter cells that are identical to the parent, but smaller!!

Chromosome

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Eukaryotic DNA

DNA in the eukaryotic cell is packaged in the form of chromatin. Which forms a chromosome.

Chromatin is a complex of DNA and histone proteins

DNA is wrapped around a core of 8 histone protein molecules, and linked to a H1 histone protein.

Each of this units is called a nucleosome

This continuing chain of nucleosomes is attached to a protein scaffold.
This scaffold loops around itself, eventually forming a chromosome.

Ecology

2011-10-29T21:32:00.003-07:00

Ecology Index:

Table of Contents:

Intro To Ecology

Nutrient Cycles:

Ecosystem Types:

Ecological Succession

Population Ecology

Global Warming

Ozone Depletion

Acid Rain

Acid Rain

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Acid Rain

Closely tied to the water cycle
Emmissions mostly from burning of fossil fuels release SO₂ (Sulphur Dioxide) and NO_N(Nitrogen Oxides) into the atmosphere.

Sources of pollutants

These compounds react with the H₂O in the clouds forming H₂SO₄ (sulfuric acid), and HNO₃ (Nitric acid).

These acids then precipitate in the form of rain and collect in fresh water lakes.

Over time this lowers the pH of the lakes, killing off most of the aquatic wildlife.

pH of acid rain

This rain can also alter the pH of sensitive soils killing trees, and damaging forests

Acid rain damaged forest

Ozone Depletion

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Ozone Depletion

Caused mainly by emmissions of CFC's into the atmosphere.
Main Sources of CFC's are

Aresol can propellants
Refrigerant gasses

CFC's enter the atmosphere and destroy Ozone (O₃)

Ozone blocks harmful Ultraviolet Light (UV) from entering the atmosphere.
Over time this has caused ignificant "Ozone holes" over the polar regions of the earth, and these are becoming larger.

Scientists fear that increased UV levels could cause increases in cancer rates in affected areas.

Global Warming

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Global Warming

Caused By Excess CO₂ in atmosphere generally caused by burning of fossil fuels by automobiles or industry.

CO₂ traps heat energy in the atmosphere slowly increasing global temperature via the Greenhouse Effect

Visible light passes through atmosphere to surface heating it.
Infared (heat) energy cannot pass out so easily and is trapped. Increasing the global temperature.

Global temperatures may have risen approx. 3⁰C overt the lact century

Overall concern is that warming may cause melting of the polar ice caps. This would raise the sea level and cause gradual flooding of areas close to sea level. Already very large portions of ice have split from the ice sheets in Antactica and Greenland.

Iceberg the size if Rhode Island calving from the Greenland Ice Sheet

Population Ecology

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Population Ecology

Vocabulary/Definitions:

Population: All individuals of a single species which exits in the same geographical area at the same time.

Population size and dispersion:

Population size greatly effects survivability of a species.
Greater the population size - Better probability of the species

Reduces effects of inbreeding
Reduces effects of catastrophic random events.

Population density is another important factor
Effects probability of individuals meeting, mating and combining genetic materials.
Population dispersion is a measure of the geographical arrangement of the individuals within a population

3 types

Randomly spaced - No apparent pattern to individual locations

Evenly spaced - Individuals are located individually according to an observable pattern

Clumped - Small populations occur in close proximity to each other. Each group, however, is separated from similar groups

Population Growth:

Population growth occurs as an exponential function. It is characterized by a slow initial population growth called the lag phase, followed by an explosive increase of population called the log phase.

In a healthy ecosystem limiting factors cause the curve to reach a stable plateau. This maximum population an ecosystem can support is called the carrying capacity

In a less than healthy ecosystem the population undergoes a crash phase where toxins, disease or starvation cause a dramatic population drop.

Ecological Succession

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Ecological Succession

Refers to the general metamorphosis of a geographic area to its most stable ecosystem.

Primary succession refers to the settlement/establishment of vegetation in an area previously uncolonized by organisms. Organism which first colonize an area are known as pioneer organisms.

Primary succession which occurs on land is termed Xerarch succession. That which occurs from aquatic ecosystems is known as hydrarch succession

Secondary succession refers to the recolonization of a geographic area, which had been previously sett;led, but somehow disrupted.
Some causes of disruption include

Fire
Volcanism
Severe weather
Agriculture
Development

Both processes result in the most stable type of biome given its geographical location. This is called a climax community.

Types of Ecosystems

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Types of Ecosystems

There are many types of ecosystems on earth.
Major classes of relatively contained ecosystems are called Biomes.
There are 3 Major classes of ecosystems

Freshwater Ecosystems

Terrestrial Ecosystems

Ocean Ecosystems

Freshwater ecosystems:

Relatively small in area ~ 1.8% of earth's surface
Support many species of life including fish, amphibians, insects and plants.
Base of food-web is found in freshwater Plankton (small microscopic organisms)

Terrestrial Ecosystems:

Many & diverse types of ecosystems. There are seven major types.
Location usually dependent on the latitude of the area, and amount of precipitation

types & locations of biomes

Types:

Tropical Rain Forest

Precipitation - 250cm/year
Little temp. variation/abundant moisture
Contains more species than other biomes.

tropical rain forest

Savannas

Precipitation 90-150cm/year
Open, widely spaced trees, seasonal rainfall
Parts of Africa, South America & Australia
3. Deserts Precipitation 20cm/year
Dry, sparce vegetation; scattered grasses
Parts of Africa, Asia, Australia, North America

Desert

Temperate Grasslands

Precipitation: 10-60cm/year

Rich soil; tall dense grasses

Central North America; Central Asia

Deciduous forests

75-250cm/year

Warm summers, cool winters

Europe; NE United States;Eastern Canada

Temperate/Deciduous forest

Coniferous forest:

20-60cm/year

Short growing season, cold winters.

Northern Asia;Northern North America

Coniferous Forest

Tundra

25cm/year
Open; wind swept; dry; ground always frozen
Far northern Asia; Northern North America

Tundra

Ocean Ecosystems:

Very large amount of Earth is covered by ocean (~75%)
40% of all photosynthesis occurs in oceans.
3 types of oceanic ecosystems
Shallow ocean waters
Deep ocean water
Deep ocean surface.

Photosynthetic plankton is base of food chain.
Only occurs in Deep ocean surface & Shallow ocean ecosystems
No photosynthesis can occur in deep ocean because light cannot penetrate deeply into water.

Nutrient Cycles

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Nutrient Cycles:

In all ecosystems, Nutrients are used by organisms and eventually returned to it again.
These are known as the nutrient cycles.
There are 3 well known of these cycles.

The Water Cycle.

The Nitrogen Cycle.

The Carbon Cycle.
The Phosphorous Cycle

The Water Cycle

Water is the most important non-organic component of an ecosystem.
Plants play an important role in retaining water in an ecosystem.

In this cycle the following occurs.
Rain falls to earth either runs off to the ocean, evaporates into air, or is held by plants and is transpired back into the atmosphere. (90% of the water which passes into an ecosystem passes through plants).
Evaporated moisture (from land, plants & ocean) condenses in the form of clouds and returns to land in the form of precipitation.

The Nitrogen Cycle

Nitrogen is an important component in the production of proteins.
Most nitrogen is inert and unusable by plants & animals.
Certain bacteria known as Nitrogen fixing bacteria, have the ability to convert N₂ gas, into NH₃ (ammonia) which is a usable form of Nitrogen.
These bacteria are often decomposers, and release ammonia when an animal is decomposing.
Others live in the roots of certain plants in a symbiotic relationship.(eg peanuts). The bacteria provides Nitrogen compounds for the plant. The plant proivides food for the bacteria.

The Carbon Cycle:

Carbon is the building block of all organic molecules.
Carbon cycle is based on the creation and absorption of CO₂ (carbon dioxide).
CO₂ is produced by plant & animal respiration & by combustion (fires, industry, cars, etc…)
CO₂ is absorbed by plants and converted to food (sugars) by plants through photosynthesis.
This food is, in turn, converted back to CO2 through respiration by plants & animals.

The Phosphorous Cycle:

Phosphorous is a critical mineral in plant growth. Due to its scarcity it often is a significant limiting factor in plant growth.
Often Phosphate-Rich detergents can disrupt an aquatic ecosystem by stimulating algeal blooms, choking off light to lower levels of water.

Ecology

2011-10-29T21:24:00.001-07:00

Ecology

Vocabulary:

Ecology - The study of how organisms fit into their environment.

Community - The organisms which live in a particular environment.

Habitat - Physical location of a community

Ecosystem - Self-sustaining collection of organisms & their physical environment.

Diversity - a measurement of the number of organisms inhabiting an ecosystem

Energy in ecosystems:

Life in any ecosystem is driven by the flow of energy.
All energy entering the earth's Biome is from the sun.
Living things are divided into 3 major categories based on how they obtain their energy

Producers - Obtain energy from their surroundings (eg.light)

Consumers - Obtain energy from consuming other organisms

Decomposers - Obtain energy from consuming wastes.

Energy in an ecosystem always flows from producers to consumers
Organisms are assigned "trophic levels" according to how many "steps" they are away from the source of their energy.

Autotrophs (like plants) occupy the first level since they obtain their energy directly from the source
Herbivores occupy the second level, since they obtain their energy from eating the autotrophs.

Carnivores occupy all higher levels, since they obtain energy from eating herbivores (and other carnivores)

Omnivores can occupy more than one trophic level since they can eat all of the above.

Note: All organisms above the the first trophic level are known as heterotrophs since they cannot make their own food, but must obtain it by consuming other organisms.

Energy flow across trophic levels is inefficient - Energy is lost between each level.

Only about 1/10 makes it from 1 level to the next.

Food Webs
Energy moves through an ecosystem in a complex pattern. The interactions of energy flow is best viewed as a food web.

Kingdom Plantae

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Kingdom Plantae

Index

Introduction

Division Bryophyta

Seedless Vascular Plants

Leaf Structure

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Leaf Structure

Leaf is a complex structure designed to maximize photosynthesis & minimize H₂O loss.

Composed of 2 major systems.

Dermal System

Fundamental System

Dermal System

Functions to allow gas exchange & protect plant

Composed of Cuticle & Epidermis

Cuticle is a waxy waterproof layer

Reduces water loss
Prevents parasites from entering plant

Epidermis is the outermost layer of cells of the leaf

Contain unusual structures called stomata

Stomata are openings allowing gas exchange in/out of leaf
Are opened and closed by function of 2 guard cells

In high heat or arid conditions guard cells close stomates reducing water loss

Stomates

Fundamental System

Also known as the Mesophyll

Contains 2 major tissue layers

Palisade parenchyma

Major fxn: Photosynthesis

Spongy parenchyma

Fxn: some photosynthesis, also storage and transport
Mesophyll also contains vascular bundles consisting of

Bundle sheath

Xylem & phloem

Cross Section of a Leaf

Stems

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Stems

Plant stems vary according to dicot and monocot.

Stems show both primary & secondary growth.

Primary growth is extension along a stem

Tissues where this growth occurs are called primary meristems

Secondary growth occurs as an increase in diameter of the stem

Tissues where this occurs are called secondary meristems

Structure of the stem

External Structure of a Stem

Monocot Stems

Monocot Stems are characterized by Vascular Bundles evenly distributed throughout the ground tissue

Vascular bundles are composed of both xylem & phloem and surrounded by a bundle sheath.

Monocot Stem

Dicot Stems

Dicot stems are characterized by vascular bundles distributed radially around the stem perimeter

Vascular bundles consist of a layered design

Phloem tissue is located closest to the epidermis

Vascular cambium (site of secondary growth) is located nearer the center

Xylem tissue located nearest the center

Woody Stems show similar tissue patterns.
Develop a layer of bark outside the epidermis of the stem
Develop annual rings which show growth of the tree over long periods of time.

Plants: Cell & Tissue Types

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Plants: Cell & Tissue Types

Plants are generally composed of specialized tissue types
Some tissues are composed of 1 type of cell - simple tissues

Some composed of more than one - complex tissues

Cell types
Parenchyma

Most common cell found in most plants
Have many functions

Storage
Photosynthesis
Secretion

Have thinner, evenly thickened cell walls

Parenchyma cells

Collenchyma

Less common than Parenchyma
Function is primarily support (but this is flexible tissue)
Have unevenly thickened cell walls (esp. at corners)

Collenchyma cells

Sclerenchyma

Less common than both above cell types
Are used exclusively for rigid support
Have primary cell walls, and thick secondary cell walls

Sclerenchyma cells

Complex Tissue Types
Xylem
Are conducting tissues in plants
Conduct H₂O and minerals upwards into plant
Are complex tissues consisting of parenchyma, and 2 specialized cells vessel elements & tracheids
Are long hollow cells which are dead at maturity

Vessel Elements & Tracheids

Phloem

Another conducting tissue in plants
Conducts food throughout plant
Complex tissue consisting of 4 types of cells

Seive tube members

Are long cells connected end-to-end dead at maturity
Connected by seive like ends called seive plates

Companion cells

Located next to Seive tubes
Assist in moving nutrients and H2O in-out of seive tubes

Fibers

Function for support

Parenchyma

Seive tube members & Companion cells

Summary of Cell & Tissue types

Angiosperms

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Division Magnoliophyta: The Angiosperms

Vascular plants possessing flowers, fruits & seeds
Most successful plants today
Reproduce sexually by producing seeds within fruits
Have extremely well developed vascular systems
Extremely important to humans
All major human food crops are angiosperms

There are 2 major classes of angiosperms

Class Liliopsida: The Monocots

Class Magnoliopsida: The Dicots

Differ in leaf structure, seed structure, vascularization, & flower structure

The Monocots:

Monocots are Herbaceous (non woody) plants

Stems have characteristic vascular system

Leaves have parallel veination (veins run parallel to each other)

Flower parts of a monocot occur in multiples of three.

Seeds have a single cotyledon (embryonic seed leaf) and have endosperm (nutritive tissue)

The Dicots:

May be herbaceous or Woody.

Leaves are usually broader and have Netted Veination.

Flower parts occur in 4 or 5's (or multiples of)

Seeds have two cotyledons, and usually no endosperm.

Seed types

Stem Types

The Flower:
Flowers have 4 main organs

Sepals

Petals

Stamens

Carpels (or pistils)

Flowers which have all 4 parts are called Complete

Flowers lacking 1 or more parts are called Incomplete

The main reproductive structures are the stamens and carpels (or pistils)

Stamens are the male part of the flower

Composed of 2 parts

Anther

Filament

Contain microspore mother cells which produce microspores which develop into pollen grains

Pistil or Carpel is the female part of the flower

Composed of 3 main parts

Stigma

Style

Ovary

Ovary contains one or more ovules. Each ovule contains a female gametophyte

Life cycle of the flowering plant

Each ovule contains a megasporocyte which undergoes meiosis to produce 4 haploid megaspores.

Three disintegrate, the 4^th divides by mitosis to produce a female gametophyte.

The gametophyte is composed of 8 haploid nuclei. Including:

1 egg
2 polar nuclei

The pollen grain is formed from the microspores produced in anther.
Consists of:

Tube nucleus

2 sperm nuclei

Fertilization:

Pollen grain pollenates flower

Tube nucleus develops a pollen tube into the ovule.

Here unique process of Double Fertilization occurs.

One sperm nucleus fertilizes the egg forming a zygote.

This develops into the plant embryo.

Other sperm nucleus fuses with the 2 haploid polar nuclei to form a TRIPLOID (3N) nucleus.

This develops into the endosperm of the developing seed.

Double fertilization

Gymnosperms

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Gymnosperms

Are Vascular plants

4 divisions of gymnosperms the 3 largest are as follows

Conifers - Cone bearing needled trees (eg.pines, firs)

Cycads - cone bearing palmlike plants

Ginkgos

Exhibit alternation of generations

Sporophyte (2N) generation is dominant.

Produce true seeds

Seed = embryonic sporophyte, stored food & protective coat
Seeds of gymnospermsare "naked"
Sporophyte generation produces heterospores - spores are not identical

Microspore (male) will develop into a pollen grain which later develops into a sperm producing male gametophyte

Megaspore (female) will develop into an egg bearing female gametophyte.

Life Cycle of the Pine

Pines produce 2 cones - male & female

Male cone is smaller and often located in the upper portion of the tree

Male cone scales contain pollen sacs where microspore parent cells undergo meiosis to make microspores.
Microspores develop into pollen grains.

.Female cone is larger (located lower on tree)

Contain 2 ovules where megaspore parent cells undergo meiosis to form megaspores.
Only one of 4 megaspores develops into mature gametophyte.

Pollenation.

Pollen grains are carried by wind to open scales of female cone.
Pollen grain grows a pollen tube to the mature egg. Where it is fertilized by 2 non motile sperm (only 1 fertilizes egg, other dies). Embryo will develop into a seed.
Fertilization requires ~15 months.
After 3 years seed is released and will germinate to form an adult sporophyte.

Pine Life Cycle

Seedless Vascular Plants

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Seedless Vascular Plants

Earliest Vascular plants
Have true roots and stems

Have true leaves
Exhibit alternation of generations, However sporophyte (2N) generation is now dominant over gametophyte (N) generation.
4 major divisions
Division Pterophyta - Ferns
Division Psilophyta - Whisk ferns
Division Lycophyta - Club Mosses
Division Sphenophyta - Horsetails

Division Pterophyta: The ferns.

General Form

Found throughout the world-more frequently in tropical areas.
Adult sporophyte has a long horizontal stem called the Rhizome.
Rhizome is vascular
Fronds extend upwards from rhizome
Roots extend downwards from rhizome

Life Cycle

Spores are released from small structures underneath sporophyte fronds called sori (sorus)

Spores grow into the gametophyte generation called the Prothallus
Is heart shaped, ~2cm across.
Contain archegonia (egg) and antheridia (sperm) similar to mosses.
Sperm fertilizes egg via rain, sporophyte grows from within archegonia

Fern Life Cycle
Division Psilophyta: The Whisk ferns.

Similar to ferns in life cycle
Sporophyte generation develops a "forked" branching pattern called dichotymous branching.
Leaflike structures lack vascularization

Division Lycophyta: The Club Mosses

Club Moss

Are usually smaller.
Life cycle differs from ferns in that gametophytes are either male or female, not both.
Archegonia are produced on female gametophyte.
Antheridia are produced on female gametophyte.

Division Sphenophyta: The Horsetails

Characterized by jointed stems
Have "Cone-like" structures at tips of stems

Division Bryophyta

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Non-Vascular Plants - Division Bryophyta

Include mosses, liverworts & hornworts

Are composed of green leaf-like structures
Have root like structures called rhizoids

Are non vascular plants

Do not contain tissues to conduct H₂O (limits their size)

Moss

Exhibit clear alternation of generations

Plants reproduce sexually, and are male and female
Male & female can occur as separate plants or on same plant
Have a dominant Gametophyte generation
This generation is haploid (N)
Produces sperm and egg

Sporophyte generation is diploid (2N)
Produces spores ONLY through meiosis (unlike fungi)

Life Cycle of moss (Class Bryopsida)

Sperm are produced in Male structure called Antheridia

Eggs are produced in female structure called Archegonium

Sperm is transferred to archegonium via rain. Feritiization results in a diploid zygote This develops into the sporophyte generation This grows from the interior of the archegonium and is composed of three parts

Foot (attaches to archegonium)

Seta - a stalk-like structure

Capsule - produces spores
Sporophyte produces spores via meiosis Spores are released and grow into more of the gametophyte generation.

Life cycle of a moss

Class Hepaticophyta: The Liverworts.

Named due to the fact that the main body or thallus of the plant can be liver-shaped
Life cycle similar to Brypohytes.
Produce special structures called Gemmae Cups. Which allow asexual reproduction
Produce balls of tissue called Gemmae.
When rain splashes into cups, gemmae are released and can develop into an independent plant

A Liverwort

Liverwort Reproductive Structures

Class Anthroceropsida - The Hornworts

Very similar to liverworts. But smaller.
Usually have leafy thallus
Cells are similar in some respects to algae.
Usually only have 1 large chloroplast in cells
Archegonia & Antheridia are usually embedded in the gametophyte thallus

Typical hornwort

Kingdom Plantae

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Kingdom Plantae

Organisms characterized by the following features

All multicellular
All Photosynthetic
All possess cell walls (containing cellulose & Lignin)

Divided into 5 basic types

Modern Algae
Bryophytes (Mosses etc…)
Club mosses
Ferns
Gymnosperms (conifers etc,,,)
Angiosperms (Flowering plants)

Plants clearly defined alternation of generations (part diploid, part haploid)

Haploid Phase is called Gametophyte Generation
Produces haploid gametes through mitosis

Diploid phase is called Sporophyte generation

Produce haploid spores through meiosis

Kingdom Fungi

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Fungi & Molds

Fungi Are eukaryotic heterotrophs.

Frequently decomposers, sometimes parasites.

Usual structure is a mass of entangled filaments called Hyphae

Hyphae can have cross walls (Septum) separating individual cells. Or have no separations.

Overall mass is called mycelium

Mushroom showing mycelium & hyphae

Reproduction:

Fungi differ from many organisms in that they:

Reproduce sexually & asexually

Longest stage of life cycle is in the haploid (N) stage NOT the diploid (2N) stage.

Asexual reproduction is accomplished through the creation and spreading of asexual spores.

Sexual reproduction is accomplished through creation and spreading of sexual spores by opposite mating types ((+) & (-)).

Divisions:
There are 3 major divisions of fungi - Based on Characteristics of sexual spores and fruiting bodies
Division Zygomycota:

Example: Black Bread mold

Hyphae produce Sporangium which form spores asexually which are released to form new mycelia.

Reproduce sexually also.

Hyphae of (+) and (-) mating types called Gametangia fuse to form a diploid (2N) Zygospore

Zygospore undergoes meiosis to produce spores which are then released

Life Cycle of Bread Mold

Sexual reproduction (see fig. 19-6, pp. 410 in text)

Hyphae called Stolons of opposite mating types (+ & -) will fuse to form a structure called Gametangia.

Diploid (2N) Zygospore is formed.

Zygospore produces sporandia which undergoes meiosis to release haploid (N) spores.

Division Ascomycetes (Sac Fungi)

Named because sexual spores are produced in small sacs called asci (ascus).
Asexual spores are produced on conidia by special hyphae called conidiophores.

Life cycle of an ascomycete

Division Basidomycota:

Include mushrooms, shelf fungi & puffballs

Examples of division basidomycota

Name derives from formation of a transient diploid (2N) stage of the life cycle called the Basidium.

Life cycle of basidiomycota

NOTE: NEVER eat a wild mushroom. Many are extremely toxic and can cause serious injury or death if eaten.

Ecological Significance:

Are valuable decomposers which function to return organic material back to the ecosystem.

Fungi can form valuable symbiotic relationships

Example are lichens which is a symbiotic relationship with algae.

lichens

Have great economic value

Yeast is a unicellular fungus used for baking and brewing.

Many mushrooms are edible

Diseases caused by fungi.

Plants are most vulnerable to molds & fungi.

It is a serious threat to agriculture some common crop diseases caused by molds & fungi are:

Potato blight
Wheat rust
Corn smut

Can cause disease in humans.

"Athlete's foot"

Ring worm

Thrush and other yeast infections

Kingdom Animalia

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Kingdom Animalia

Index

Properties of Animals

Phylum porifera

phylum cnidaria

Phylum Platyhelmenthes

Phylum Rotifra

Phylum Nematoda

Phylym Mollusca

Phylum Annelida

Phylum Arthropoda

Phylum Echinodermata

Phylum Chordata (The Urochordates)

Phylum Chordata (The vertebrates)

Phylum Chordata(Vertebrates)

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Phylum Chordata: The Vertebrates

Subphylum Vertebrata

Seven extant classes
- First 3 commonly called fishes
- Remaining 4 called tetrapods (4 feet)
- All possess some form of segmented vertebra

Class Agnatha

Commonly known as Jawless Fish

Include hagfish & Lampreys

Lack paired appendages
Lack bony skeleton
Lack jaws
Usually have circular sucking mouthparts
- Lampreys parasitize other fish

Class Chondrichthyes

Include sharks & rays
Very successful class
Called cartilagenous fishes because skeleton is cartilage not bone
Approx. 750 species
Have paired appendages
Many have acute senses
Sharks have a lateral-line system
- Allows shark to detect water pressure changes

Class Osteichthes

Called Bony fish
Most diverse of all fish
Have skeleton made of bone
Have paired fins
- Allowed evolution of 4 limbed amphibians (tetrapods)
Possess scales for protection
Have bony flap called operculum
- Allows water to be drawn over gills by fins

Have Swim bladder
- Gas content can be manipulated allowing for changes in bouyancy

Class Amphibia

First vertebrates to inhabit land

Most are 4 limbed (tetrapods)

Include frogs, salamanders & caecilians

Include 3 orders

Urodela ("tailed ones" - Salamanders)

Apoda ("tail-less ones" - Frogs & toads)

Caecilia ("legless ones")

Lack internal fertilization & amniotic eggs
- Reproduction must occur in H₂O

Most species undergo metamorphosis

Larval stage (tadpole) is usually an aquatic herbavore
Lacks legs, respiration is through gills
Develops into tetrapod adult (usually carnivorous)

Frog Metamorphosis

Gas Exchange is usually through a combination of lungs, gills and skin

Class Reptilia

Includes lizards, snakes, turtles, and crocodilians

Over 7000 species
Possess several advanced features over amphibians
All adaptations towards independence from H₂O
Possess scales containing keratin

Keratin is a waterproofing protein which prevents water loss in an organism

Possess an amniotic egg.

Prevents water loss of embryo. Allows for eggs to be laid on dry land
Combined with internal fertilization, allows reptiles to reproduce independently of water

Reptilian Amniotic Egg

Reptiles are "cold blooded" or ectotherms

Cannot internally regulate body temperatures
Reptiles can regulate body temperatures behaviorally (eg. Basking or swimming)

Nutritional requirements are lower than warm blooded animals

Modern Reptiles
3 Extant orders of reptiles

Order Chelonia (Turtles)

Inhabit aquatic and terrestrial environment.
Are herbavores, carnivores, and omnivores
Characterized by possessing a dorsal hard shell
- Made from bone, extensions of backbone and rib cage

Order Squamata (Lizards & Snakes)

Most numerous & diverse of the reptiles
Most relatively small Although monitors and their relatives can grow to 6' in length
Herbavores, carnivores & omnivores
Most able to exhibit some form of hibernation

Order Crocodilia (Crocodiles, Alligators, & Caimans)

Largest extant reptiles
Primarily aquatic they are true reptiles
Inhabit warm, tropical climates
Order most closely related to the dinosaurs

Class Aves

General Bird Anatomy

Evolved from dinosaurs during Mezozoic era.

Aminotic eggs and scales on legs reminants of reptilian origins

Almost all adaptations of these animals are made for flight.
- Made of keratin

Forelimbs developed into wings

Honeycombed, light bone structure

Types of feathers

Absence of some organs

Females usually have 1 ovary
Absence of teeth lighten head
- Replaced by gizzard in abdomen & beak
Beak made of keratin
Proven very adaptable structure, having a variety of shapes for differing diets

Beak Types

Birds are the first extant endothermic organisms

Regulate body temperature internally

Metabolic rate is therefor increased and is compensated by the following adaptations

Efficient circulatory system with a 4 chambered heart
Efficient lungs
Increased nutritional demands

Birds have well developed senses especially vision

Larger brains than reptiles

Reproduction is through hardened amniotic eggs

Since birds are endothermic, these must be kept warm by parents

This behavior called brooding

Bird amniotic egg

Birds have also adapted feet for varying ecological niche

Modern Birds

Over 8600 species & 20 orders of birds
Classified into 2 general groups
Flightless species including ostrich, emus, & kiwis are known as ratites

Lack sternal keel on breastbone
Lack strong breast muscles needed for flight

Ostrich: a ratite

Other species capable of supporting flight called carinates

60% are "perching birds" called passeriforms

Possess a sternal keel on breastbone

Support strong breast muscles required for flight

The sparrow: A passeriform carinate

Class Mammalia

Approx. 4500 species of mammals
Evolved from mammal-like reptiles called therapsids in the triassic period
Diversified greatly following the extinction of dinosaurs

Mammilian Characteristics

Have Hair
Made of keratin
Aids in maintaining body temperature

Endothermic
Maintain body temperature internally

Have efficient respiratory system including a diaphragm

Efficient circulatory system with a 4-chambered heart
Most possess placentas and give birth to live young
Have mammary glands to produce milk for offspring
All show parental care of offspring
Have largest brains of all vertebrates
Have differentiated teeth
- Unlike earlier vertebrates, several different teeth can exist in mammal jaws
- Eg. The molars & incisors in the human jaw

Types of Mammals
Monotremes

Early branch from reptilian line
Include platypuses & echidnas (spiny anteaters)
Only group to lay eggs (reptilian in structure)
Have mammary glands to feed young

Duck-Billed Platypus

Spiny Anteater

Marsupials

Include opossums, kangaroos & koalas
Do not develop placentas
Give birth to young very early
Fetuses complete development in pouch called marsupium

Mammary glands found in pouch nourish young until development is complete

Opossum

Kangaroo

Koala

Placental Mammals

Complete embryonic development in uterus
Joined to parent by organ called placenta

Only "disposable" mammal organ

Discarded following birth

Exchanges gasses, nutrients & waste between mother and fetus

Human Placenta

Phylum Chordata(invertebrate)

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Phylum Chordata The invertebrate chordates

Charactertistics of Chordates

All chordates possess a notochord.
Long felxable rod between gut & nerve cord
Runs most of length of animal
Possess a dorsal, hollow, nerve cord

Possess pharangeal slits

Muscular post-anal tail

Subphylum Urochordata

Commonly called turnicates

Sessile marine animals as adults - Motile as larva
Larva possess a clear notochord which is less evident in adults
Filter feed through use of siphon

Subphylum Cephalochordata

Commonly known as lancets

Have all features of the ideal chordate
Bury selves in sand, and filter-feed through mouth

Phylum Echinodermata

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Phylum Echinodermata

Share common features with chordates
- Radial Cleavage
- Deuterostomes (Blastopore becomes anus)
- Development of true coeloem

Usually slow moving or sessile
Usually are radially symmetrical
Body parts usually radiate from center (frequently as 5 spokes)
Possess a thick calcium plate endoskeleton surrounded by a thin skin layer
Possess a unique Water Vascular System, which continues throughout animal and extends into extensions called Tube Feet.
- Functions for locomotion, feeding, & gas exchange.
- Reproduce sexually or through regeneration.

Class Asteroidea

Include sea stars
Usually have 5 arms radiating from central disk
Tube feet located underneath each arm used for locomotion & grasping prey
Feed on mollusks by pulling shells apart and extending stomach outside the mouth into the bivalve. The bivalve is digested within it's shell.

Internal anatomy of a seastar

Feeding

nSeastars feed on mollusks by pulling shells apart and extending stomach outside the mouth into the bivalve. The bivalve is digested within it's shell. The sea star than re-ingests its stomach

Reproduction

nCan reproduce sexually by releasing sperm and egg.

nCan reproduce by regeneration

Class Ophiuroidea

Include Brittle Stars
Distinct central disks with long tube-like arms
Lack suckers
Move by serpentine motion of their arms
Are usually deep ocean scavengers

Class Echinoidea

Include Sea urchins & sand dollars

Lack arms, but possess tube feet
Many species of urchins possess poisonous spines used for defense

Class Holothuroidea

Include Sea cucumbers
Are elongated along oral-anal axis
Lack spines and have reduced endoskeleton.
Do possess tube feet and water vascular system

Class Crinoidia

Ancient class of animals
Include sea lilies

Filter feeders with arms radiating from mouth
Most are sessile, but some can move