Friday 26 September 2014

All Fossils Are Transitional Fossils

One aspect of evolution which creationists either feign ignorance of or have been fooled by creationist pseudoscience frauds about, is how exactly one species 'transitions' into another over time, according to the scientific theory of Darwinian evolution. The same feigned or genuine misunderstanding can be seen in creationist circles concerning the evolution of an entire phylum or class from an earlier one.

In fact, spend a few minutes perusing any social media which deals with creationism vs evolution and you will quickly discover that creationists seem to hold three different understandings of the process simultaneously, all of them wrong. This probably comes from a need to dismiss evolution without giving those reasons too much consideration so three different reasons are better than one. Those three laughably infantile views seem to be:

  1. Evolution says that one species suddenly changes into another either by the parent species literally giving birth to members of a new species - "No one ever saw a chimpanzee give birth to a human", "If apes became human why are there still apes?"
  2. Evolution happens through one, or maybe a few, intermediates, as though there is some sort of plan to change one species into another - "Why are there no crocoducks?", "Why are there no half-men/half-monkeys?"
  3. Evolution happens through a series of discrete 'transitional forms' where this form is halfway between two other species - actually a slightly more sophisticated form of the second fallacy - and the TOE says there will be a fossil record of this transitional form.

The first two of these are of course infantile and idiotic and designed to parody the science so those ignorant of it can feel smugly superior to 'those mad scientists who believe that rubbish'. As such, there is probably little any rational person can say which would persuade the loons that that's not what science says.

But the third is a more subtle misrepresentation of the science and depends on ignorance about what exactly evolution is and the bare-faced lie that the TOE hinges on the existence of this supposed series of transitional fossils for every species, either living or extinct and that the theory will be destroyed in this series can't be found, as though the TOE is a theory about fossils.

Of course, as any evolutionary biologist will explain, the fossil record is only a small part of the mass of evidence for evolution. The non-fossil evidence for evolution is so overwhelming that geologists would have to develop theories to explain their absence, if there were none. The 'gaps' in the fossil record are exactly what we would expect given the rare and special nature of the event, at least so far as non-marine species are concerned. Indeed, if there were continuous series of fossils easily found in the geological column for every species, this would be so hugely unlikely that it would hard to argue that it hadn't been designed. The presence of very many continuous 'transitional' series where none should be expected would actually be evidence for intelligent design. To the acute embarrassment of creationists, the lack of these series argues against their currently fashionable daft idea.

Nevertheless, there are numerous examples of good series of fossils over time in special circumstances such sedimentary rocks formed over tens of millions of years during the evolution of some marine species, so these fossils, perfectly arranged in order in the geological column, can act as index species by which to date other rock formations.

But the entire argument is based on a false premise anyway. It is based on the parody that somehow a 'transitional' fossil is different to an 'ordinary' fossil. This does what it was intelligently designed to do, and enables creationist frauds to fool their target market with the claim that there are no transitional fossils. Ask them what they would expect a transitional fossil to look like and you'll get the fall back to the even more infantile parody about crocoducks, half-men/half-monkeys or fish with frog legs.

In fact, of course, every single fossil is transitional, as is every single living individual. Every individual, whether they were fortunate enough to get fossilised or not, represents a snapshot of their species at that stage in its evolution, so every fossil is a snapshot of that species as it was then - precisely transitional between its parents and its offspring. It will be indistinguishable from both, of course, because change is small, gradual and spread across the entire genepool and even progresses at different rates in different parts of the range, or even in different directions. But look at a fossil of one of its ancestors from 50,000 or 100,000 years earlier, or one of its descendants from 50-100,000 years into its future and you may see changes. In some lines these changes will be be large; in others it may be small. If we could look at the DNA we would probably see very many changes that don't express in the phenotype. Look at the fossils a few million years either side and you might well see what would be different species had they lived contemporaneously.

And that brings me at last to my rainbow strip representing the visible spectrum. Imagine the change in colour from left to right across the rainbow represents change in an evolving species over time. The colour obviously change but where exactly are the transitions? In fact, they are not missing, they are everywhere. Every vertical band of colour is transitional and yet visually indistinguishable from the bands either side of it. And yet, despite this absence of obviously transitional colours, the colour has changed from red to violet. What would you expect a series of, say, half a dozen samples randomly selected from this strip? Would any one of them look transitional?

This is exactly how a species changes gradually over time as small changes get selected by the environment and so become concentrated and accumulated in each generation so each generation varies only slightly from the previous one but by a larger and larger amount from earlier ones as time goes by.

And taxonomists draw often arbitrary lines across the rainbow and give names to the colours such as 'yellow', 'green' or 'blue' whilst never being able to say precisely where that line should be or to make it less fuzzy. But creationist pseudoscientists will tell you that changing from one side of that fuzzy line to the other is impossible without being able to explain why an arbitrarily drawn line, or a decision made by a taxonomist, can change retrospectively what can be seen to have happened.

Whatever would these frauds do for a living without such a large, ignorant and gullible market to feed off in a people who don't feel important enough unless they believe they have a close personal relationship with a creator of the Universe who made it all just for them, and who will clutch at any straws to cling to that daft notion?

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1 comment :

  1. @Rosa: You're strongly supported by an article in The Scientific American, written byTanya Lewis; see: .

    That article is about both microevolution and macroevolution. How dinosaurs successively developed birdlike features and how then evolution split up in two directions: 1) continued development of dinosaurs but also 2) the bird lineage. Meaning that all birds evolved from dinosaurs, but not all dinosaurs became birds.

    Two definitions: Macroevolution = Evolution on a large scale extending over geologic era and resulting in the formation of new taxonomic groups. Microevolution = Evolution resulting from small specific genetic changes that can lead to a new subspecies (for example different breeds of dogs).


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