Vestigial structures - one of the best lines of evidence for evolution

The existence of atavisms and vestigial structures was one of the lines of evidence for evolution Darwin advanced in his Origin of Species, and to this day remains one of the most misunderstood arguments for evolution. Special creationists still think that vestigial means useless, but as Darwin pointed out:

"[a]n organ serving for two purposes, may become rudimentary or utterly aborted for one, even the more important purpose, and remain perfectly efficient for the other....an organ may become rudimentary for its proper purpose, and be used for a distinct object." [1]

In other words, a structure is vestigial if it has lost its original function, irrespective of whether it has secondarily acquired a new function. Examples of vestigial structures include the inner wings of flightless beetles that are atrophied and unable to perform their original function of flight, and the human coccyx, which no longer functions as a tail, but has secondarily acquired new function. The presence or absence of function is not relevant as to whether the structure is vestigial.

This short video shows a number of vestigial structures in the human body, and shows how they provide evidence for common descent - they are features inherited from a remote ancestor which are present, but no longer have the same function that they do in related species with whom we share common ancestry.




Reference

1. Darwin C. " On the Origin of Species by Means of Natural Selection" (1859: John Murray: London.)

"Do Your Own Research" - Crackpots and the Burden of Proof

Over the years I have been defending mainstream science from crackpot views such as YEC, homeopathy, geocentrism, and germ theory denialism, I've noticed that when advocates of these pseudoscientific views are losing the argument or are asked to provide credible evidence for their views, quite often, they respond with a passive-aggressive 'do your own research', and leave the debate. "Do your own research," of course is an evasive rhetorical trick which ignores the fact the person advocating the minority view has the burden of proof and is obliged to defend that view. As a rule, the moment you hear anyone pushing a fringe view utter those words, you can immediately dismiss them as a poorly informed crank. Here's why.

Faith and Wisdom in Science: observations from a recent Norwich science and faith conference

Last week, Tom McLeish, Professor of Physics at Durham University and chair of  the Royal Society’s education committee participated in an afternoon session at Norwich in which a group of  "lay ordained, religious believers (of different kinds) and not, and including two working scientists" [1] fielded questions from a group of sixth form students on questions related to science and faith. The range of questions asked by the young people included comments about creationism, the 'God of the Gaps', free will, and the need for religion to prove itself to be valid. Those are pertinent questions which have been asked in our community but poorly answered or even ignored, and one is left lamenting how mainstream Christianity leaves our community far behind in being able to raise and answer these questions in an intellectually honest manner.

A "call for calm" on disussions related to Genesis published in The Christadelphian - in 1965

In the mid-1960s, the UK Christadelphian community attempted to come to terms with the evidence for human existence that predated the earliest reasonable date for Adam. Time has of course shown that the evidence for human evolution from the fossil and genomic data is beyond rational dispute, but what characterised our community half a century ago was a willingness to discuss things in a spirit of moderation and love. While browsing back issues of the magazine, I noticed this 1965 letter which managed to emphasise the need both for ecclesial autonomy and a rational, calm approach to discussions. We would do well to emulate that calm, rational approach today.

Refuting common YEC attacks on evolutionary creationists

In my last post, I commented on the all-too common phenomenon of privileged people complaining of being persecuted when their cherished beliefs are questioned. A classic example of this can be seen where YECs react poorly to problems with their worldview being pointed out, even when the questions are posed calmly. Worse still is the victim blaming where those who point out theological and scientific problems are branded as divisive.

Over the years, I have seen many YEC attacks which tend to fall into several predictable classes. These are composites of various YEC comments I have seen over the time I have been following the debate. One hopes that by highlighting them, YECs will endeavour to avoid repeating these fallacious arguments.

YECs: being corrected or contradicted does not mean you are being persecuted.

Many special creationists in our community need to take to heart Ralph Waldo Emerson's comment, “Let me never fall into the vulgar mistake of dreaming that I am persecuted whenever I am contradicted.”A related sentiment that pops up in online debate is, "when one is used to privilege, equality seems like oppression." Over the years that I have been involved in the creation-evolution debate, I have seen more than enough of special creationist behaviour to realise that too many of them confuse persecution with losing their privileged status as the sole arbiters of how the creation narratives are interpreted, or with having those interpretations challenged or refuted. In short, rather than accept that their views have been shown to be false, these special creationists are quick to claim victim status.

I saw a particularly egregious example of this recently in an online debate, where a special creationist seriously claimed to be persecuted by evolutionary creationists. The special creationist was quickly corrected by another commenter who noted that persecution was being killed for one's faith, and not having someone disagree with views expressed in debate. It would be harder to find a clearer example of Emerson's adage than the piteous lament made by the YEC. More to the point, the fact that evolutionary creationists in our community are being harassed and even excommunicated makes the claim by that special creationist of persecution frankly offensive.

Neanderthal ancestry and depression risk - why nothing in medicine makes sense except in the light of evolution

Evolutionary biology, as I have pointed out repeatedly is of practical utility for medicine in areas ranging from the classics such as rational antibiotic prescription, tumour biology, and epidemiology, through to understanding the many design flaws and quirks in our anatomy and genetics which make sense only when seen as a result of our evolutionary origins. These facts readily explain both the trend towards making evolutionary biology a basic clinical science for medical students, and the growth in the new field of evolutionary medicine.

They also go a long way to pointing out why intellectually honest, informed doctors are incredulous when people tell them that evolution is 'science falsely so-called'. It's impossible to deny evolution when you can see bacteria evolving drug resistance, have a knowledge of the multiple design flaws in our anatomy that can be explained only by evolution, know from clinical genetics that many genes have coalescent times stretching back hundreds of thousands of years, or are aware of the multiple retrotransposon fragments in identical places in human and ape genomes.  In fact, we've moved beyond the novelty of seeing the indelible hand of evolution anywhere from gross anatomy down to the genomic, and are now building on the fact of evolution to see whether Neanderthal ancestry is linked with the risk of disease. It's not only game, set and match for evolution. We've moved onto the next round of the competition.