Without Excuse

Approaching The Origins Debate with an Open Mind

2011-03-16T11:02:00.000-07:00

Produced by "What You Ought to Know", this humorous video provokes us to think objectively and fairly about the way we draw conclusions based on evidence of natural selection and speciation. Are "ID" and "evolution" scientific theories or philosophies to explain our scientific findings?

Tiktaalik roseae

2011-03-16T10:51:00.000-07:00

Background:

In 2006, a team of scientists unveiled the discovery of Tiktaalik roseae, a fossil fish known as the 'fishapod' [non-technical introduction]

A Devonian tetrapod-like fish and the evolution of the tetrapod body plan [original scientific paper]

Perspectives:

Embryology

2010-03-28T19:14:00.000-07:00

Background:

Darwin's Evidence: Embryology [lecture notes]

Perspectives:
Icons of Evolution [Google eBook chapter]

Embryology and Evolution [scholarly article]

Wells and Haeckel's Embryos, A Review of Chapter 5 of Icons of Evolution [online article]

Video:

Pick Your Way to Subscribe

2010-03-23T23:08:00.000-07:00

Keep up to date with recent posts and announcements by subscribing via email, a news reader (Google reader, for example), our facebook fan page, or our twitter page - pick whichever is most convenient for you! Or, just follow us on this page using your Google account (create a free Google account with any valid email address here). Feel free to contact us directly with comments, questions, or suggestions, at withoutexcuse1@gmail.com. Thanks for joining this blog community!

Darwin's Finches

2010-03-21T14:17:00.000-07:00

Background:
Speciation and the Galapagos Finches [online article]
In The News:
Scientists Watch Darwin's Finches Evolve [msnbc news article]
Perspectives:
Icons of Evolution: Darwin's Finches [online article]
TalkOrigins Resources on Darwin's Finches [online archive]
Icons of Evolution: Science or Myth, Darwin's Finches [Google eBook]
Detailed historical and geographic study:
Darwin and his Finches: The Evolution of a Legend, by Frank J. Sulloway [scholarly article]
Video on Evolution and the Galapagos Finches:

Carbon Dating

2010-03-19T12:24:00.000-07:00

Accuracy of Fossils and Dating Methods [online article]
BBC: Radiocarbon Dating [online article]
The Usefulness of Carbon 14 [online article]

Background:

Most carbon atoms in our atmosphere have six protons and six neutrons in the nucleus, yielding a total mass number of 12. A small fraction of naturally-occuring carbon atoms, however, have extra neutrons, resulting in mass numbers of 13 or 14. C-14 is unstable and decomposes to smaller isotopes (C-13 and C-12) at a predictable rate. This rate is described by a "half-life" of 5700 years. In other words, half of the entire fraction of C-14 will decompose in approximately 5700 years. Thanks to this natural phenomenon, scientists are able to estimate the age of carbon-containing materials (bones, plant material, etc.) by measuring the fraction of C-14 remaining in the sample, a test referred to as Carbon Dating (see informative video below)

Radiocarbon dating, as it is also called, is not the "be-all, end-all" of dating. Consider these limitations:

First and most obvious, is the fact that samples must be carbonaceous. Don't waste your time attempting to carbon-date a rock.
Also, samples must be less than ~100,000 years old, after which all traceable amounts of C-14 have disappeared. (Some sources report a limit of 50,000 years, while some report 130,000 years, but the point still stands. Time is a limiting factor.)
Even for recent, carbonaceous samples, this method of dating may not be reliable, since it lies on the precarious assumption that atmospheric C-14 content has remained relatively constant throughout time.
Only terrestrial samples yield accurate estimates, since almost no C-14 is present in dissolved carbonate. As a result, scientists in the past have estimated the age of clams to be over 50,000 years old using carbon-dating, while the clam was still alive!
Still other complications have arisen, when historical artifacts from a known time period are assigned a date 20% older than expected.

Despite these limitations, carbon-dating has been calibrated by ice-core, tree-ring, and lake varve measurements supposedly as far back as 15,000 B.C., and confirmed by innumerable cases. Scientists accept varying degrees of reliability when it comes to carbon-dating, because of these contradicting forms of evidence. A few different perspectives, and further discussion, are shared in the articles above.

Anti-Biotic Resistant Bacteria

2010-03-16T00:20:00.000-07:00

Natural selection and evolution of antibiotic resistance in bacteria [online article]
The "Evolution" of Antibiotic Resistance [online article]
Compensatory Mutations, Antibiotic Resistance and the Population Genetics of Adaptive Evolution in Bacteria [journal article from Genetics]

Navigating Topics

2010-03-15T23:54:00.001-07:00

As new posts are added to this site, they will show up on the home page, making it easy to keep up to date with recent additions. Each post will have one or more "tags," allowing you to filter for posts in a given topic, such as Geology. These topics can be accessed by clicking on the links to the right. (For illustration, this post has been tagged with all the topics existing at this time).

Welcome.

2010-03-15T21:24:00.001-07:00

Welcome to Without Excuse, a site designed for the exploration and discussion of the truth concerning the origins of life. Our goal for this site is to develop a portal to the vast array of information in print and on the web concerning the evolution-creation debate. We hope this site will reach a diverse and widespread audience - from novices to experts. Your thoughtful, respectful input is greatly encouraged, so please subscribe, invite your friends, and join the conversation!