Non-fossil Evidence Supporting Evolution

The claim is often made by creationists that the lack of "transitional forms" in the fossil record proves that evolution is false. There are obvious problems with this claim. First of all, even if you accept this premise, the lack of proof for evolution is not the same as proof for creationism. Disproving one theory is not sufficient to prove an alternate theory--the alternate theory needs to be proved on its own merits and evidence. It must make predictions (like the theory of evolution does), and then confirm those predictions by finding or demonstrating further evidence (like the theory of evolution does).

Second of all, the statement is based on a poor understanding of evolution and the fossilization process in general. The conditions under which fossils are formed are very rare, and the likelihood that any given organism will become a fossil is vastly low. The "transitional" species (for example, fish evolving the ability to walk on land, dinosaurs evolving some bird-like traits but still retaining dinosaur traits, etc.) would be confined to a small geographic location, and (relatively speaking) short time period, so the likelihood of the right conditions for fossilization coming together for of a member of one of those "transitional" species would be particularly low. There are undoubtedly countless species that have lived and evolved that we will never know about, just due to the fact that fossilization is so rare. If we never found any "transitional" fossils, the rarity of fossils in general could easily explain it.

Thirdly, the statement is false anyway--there are "transitional" species in the fossil record. Technically, since evolution is an ongoing process, all species are transitional, but we even have examples when using the definition set up by creationists. Archaeopteryx, many species in the evolutionary lineage that lead up to modern day horses, Ambulocetus (the "walking whale"), Tikaalik, various proto-humans in our own evolutionary lineage, and many, many more. Did I mention there are many more?

Not convinced? Have excuses for why each of these fossils does not actually, as common sense and science would have us believe, represent a transitional species? That's OK, because fortunately there is plenty of independent evidence that also supports evolution.

Molecular Evidence

Around this time last year, Dr. Zachary Moore started a series of episodes in his fantastic Evolution 101 blog and podcast that explained the molecular evidence for evolution in detail. His source was primarily Dr. Douglas Theobald's 29+ Evidences for Macroevolution, which he "dumbed-down" into less technical terms. I won't bother reproducing Dr. Zach's detailed descriptions, instead I'll use what information I gleaned from both sources to further "dumb" them down into shorter and more concise summaries.

1. Protein Functional Redundancy (Dr. Theobald / Dr. Zach)

The idea here is that there are certain proteins that are encoded in DNA that all living things have, because they are necessary for life. Humans have them, horses have them, flies have them, fungi have them, bugs have them, bacteria have them--every living thing has them. They are called ubiquitous proteins. There are, for all intents and purposes, an infinite number of possible ways these proteins could be constructed to carry out their function. Let's consider the two possible scenarios that I'm addressing here, and what they would predict about these proteins.

Evolution says that all living things evolved from a common ancestor. It would predict that these ubiquitous proteins are more similar in closely related species (for example between humans and chimps) than in less related species (for example between humans and yeast).

Creationism might predict either a) that these proteins would be identical in all living things (God's blueprint), or b) that these proteins would be different in each species (perhaps specifically tailored for maximum efficiency in each one).

When we look at the data, it overwhelmingly supports evolution. As evolution predicted, the similarity of these proteins very closely correlates with how related the species are (identical or very similar in closely related species, and more and more different as you go to species that are less and less related).

But wait a second, how do we know that this isn't just a result of prediction b) that creationism may make above (ie., that God has not simply tweaked his protein design to better accommodate each species' specific requirements)? Well, scientists have tried swapping these proteins between very distantly related species (for example, humans and yeast). The results show that the proteins function equally well, regardless of how they are constructed. This means that there is no reasonable explanation why God would have made them differently in the two different species (and, furthermore, to make them different in a way that would exactly correlate with how natural evolution would predict them to be).

2. DNA Coding Redundancy (Dr. Theobald / Dr. Zach)

This is related to point 1. above. Basically, the patterns for constructing the ubiquitous proteins are stored in an organism's DNA. I mentioned before that there are essentially an infinite number of ways you could construct the proteins to achieve their function. There is also an essentially infinite number of different DNA sequences that could code any given protein. When we look at the proteins in humans and chimps, we see that they are very similar or identical, in contrast with less similarity between less related species (despite there being no functional reason for the differences). Since this is also true for the DNA sequences that code the proteins (again, with no functional reason for them to be similar or different between any species), it reinforces and supports the protein evidence for evolution for the same reasons mentioned above.

The only way that creationists can explain this evidence is to say that God designed the proteins and their DNA coding sequences this way for reasons that we can't possibly understand. I would posit that there really is only one reason that God could possibly have to design things this way, assuming that he did. That would be to ensure that anybody with the capability to investigate this evidence would unquestionably arrive at the conclusion that evolution and common ancestry is true, thus damning himself to Hell for all eternity. Boy, if God did create us, he sure is a dick!

3. Transposons (Dr. Theobald / Dr. Zach)
4. Redundant Pseudogenes (Dr. Theobald / Dr. Zach)
5. Endogenous Retroviruses (Dr. Theobald / Dr. Zach)

I'm grouping these final three points together, because they are basically describing three different things that support evolution in the same way. The previous two points described how similarities and differences between the coding parts of DNA strongly support evolutionary theory. These last three points describe how certain aspects of the non-coding part of DNA (or "Junk DNA") also provides strong evidence in support of evolution.

Transposons are "mobile" chunks of DNA code that can move around within the genome, pseudogenes are vestigial genes that no longer have any function in the DNA, and endogenous retroviruses are pretty much what they sound like--viruses that infect DNA and get passed on to the organism's offspring in the genome (and eventually, over multiple generations, mutate into inactive "fingerprints" in the DNA of a species). The insertion or creation of each of these things into an organism's genome is controlled by completely random circumstances, and each one is passed on genetically to offspring. What this means is, if two separate organisms have identical or very similar copies of these "fingerprints" in their genome, it means that they are almost certainly genetically related (since the chance that the same random fingerprint would arise in both independently is astronomically low). It is the same concept that is used in paternity tests (looking at similarities in DNA that can only be explained by genetic relationships). So, essentially, using the same concepts that allow us to look at the DNA of two brothers and determine that they had the same parents, we should be able to look at the DNA of members from two different species to determine if they had a common ancestor.

Again, the evidence strongly supports the theory of evolution and common ancestry--related species have many of these DNA "fingerprints" in common with each other. For example, chimpanzees and humans have several in common, indicating that we have a common ancestor. Evolutionary theory would also predict that less related species would have less of these fingerprints in common, and this is also the case. For example, DNA fingerprints that are shared between hippos and whales (which evolution predicts are closely related) are not shared with other, less related mammals (such as pigs and camels). Again, this data can only be explained by accepting that these species evolved from common ancestors.

Since we can actually watch these processes take place in a science lab (see these "fingerprints" created in the genome, and get passed along to offspring), it means that creationists must accept that God also created this process--again apparently with no good reason other than to "trick" scientists by making it look like evolution and common ancestry is true.

Biological/Anatomical Evidence - Vestigial Structures

Penguins have hollow bones and wings like other birds do, but can't fly. Blind mole rats have eyes like other animals do, but can't see with them. Whales have leg bones, but no legs. Dandelions produce petals and pollen, but don't use them for reproduction like other flowers. Humans get goosebumps like other fur-covered mammals, yet don't have any fur to raise. Pythons have pelvis bones, but no legs. There are countless other examples of structures in organisms (even at the molecular level) that either perform no function, or completely different and lesser functions than similar structures in other closely related organisms. These are structures that are clearly meant for a particular function (as can be observed by their working counterparts in other species), but do not.

This evidence can be perfectly explained by evolution and common ancestry. And, again, evolution can make predictions about vestigial structures, which are supported by the evidence. Using phylogenies constructed using independent evolutionary evidence, any vestigial structures in a species should have working counterparts in other closely related species, and must necessarily derive from a working structure in a previous ancestor. As it turns out, this is absolutely the case.

Any competing theory (for example, creationism) should also be able to explain the existence of vestigial structures--not only occurring in individual species, but in entire groups of species (which evolution says evolved from a common ancestor), and should also address their structural similarity to working structures in other species. For example, vestigial veriform appendixes in both humans and chimpanzees, which are non-functioning versions of cecums in other herbivorous species. One could argue that these vestigial structures do perform some minor secondary function, and thus are not vestigial (even though complete non-functioning is not a requirement for a structure to be considered vestigial), but it still does not address the issue that they closely resemble and are obviously derived from working counterparts in related organisms or ancestors. Additionally, evolution can account for the alternative functioning of these vestigial structures (ie., they evolved to perform the new function after their primary function was no longer necessary for the organism's survival).

So What Does It All Mean?

I've only covered a few of the many kinds of non-fossil evidence that support evolution--there is a lot more that is covered in great detail elsewhere on the web and in books (I recommend Dr. Theobald's essay on TalkOrigins.org). It really is not possible to deny the fact that evolution occurs, and that all species share common ancestors with other species, without completely ignoring the incredibly overwhelming evidence.

Sure, creationists also have "explanations" for all of the evidence presented here and elsewhere (generally, "God did it that way--I don't know why, but He did.") As I said before, if you believe that, then you are basically saying that God is a jerk who wants evolution to seem absolutely true. If you believe God created everything, then you believe that he did so in a way so as to perfectly remove any trace of his existence from the equation--as though he wants us to come to the inescapable conclusion that he didn't have anything to do with it, thus ultimately damning anyone who is actually curious enough to check the evidence out for themselves to eternal damnation.

What a prick!



Other References:
http://www.harunyahya.com/articles/20evolution01.php
http://en.wikipedia.org/wiki/Transitional_fossil
http://en.wikipedia.org/wiki/Fossil#Rarity_of_fossils
http://www.trueorigin.org/theobald1a.asp
http://www.talkorigins.org/faqs/comdesc/camp.html
http://www.talkorigins.org/faqs/comdesc/section2.html#morphological_vestiges
http://en.wikipedia.org/wiki/Vestigial_structure
http://www.answersingenesis.org/tj/v3/i1/appendix.asp