One of the pieces of evidence that evolutionists like to tout for their theory is something called structural homology. They claim that this homology points to common ancestors between various creatures which share it. The question that needs to be asked is “Does this support evolution? Or is there another way of looking at homologous structures which is non-evolutionary?”. This article will examine what homology is, how it fits into the origins debate, and why it exists.
The first part of this discussion is discovering what homology actually is. The following definition is from Biology online and was one of the clearest ones I could find. “In evolutionary biology, homology pertains to a state of similarity in structure and anatomical position but not necessarily in function between different organisms. They may arise from a common ancestry or evolutionary origin.” In other words, homology is the similarity of various structures across different organisms. The functions of those structures do not have to be the same in order for homology to exist. According to the evolutionist, these homologous structures exist due to common ancestry and evolutionary relationship between the organisms sharing homology.
The idea of homology was not new to evolutionists. The term itself was coined by Sir Richard Owen, who, interestingly, also coined the term “dinosaur”. However, Owen was not the first to propose the idea. It was proposed as far back as the Greek philosopher Aristotle, and with good reason. No scientist could look at the bone structure of several vertebrates and conclude that there are no similarities. There are, across a range of species. If you were to compare the arm of a chimpanzee to the front paw of a cat, for example, you would find that, while the limbs do substantially different things, their structure is similar. Further, the chemical structure of the bone itself is either identical or extremely similar. Even in birds, where the bones are hollowed out to lighten the load and permit easier flight, the chemical structure of bone is still remarkably similar. Evolutionists have seized on this similarity as evidence that these creatures all had a common ancestor.
So why is their homology? Why do organisms across the kind boundary share similar structures? Evolutionists point to common ancestry. They claim the reason for the similarity is that organisms all originated from a single common ancestor millions of years ago. This argument is somewhat akin to saying that because two Kia vehicles have similar parts, they both developed from a horse-drawn chariot millions of years ago. The two Kias have similar parts because they had a common designer, not a common ancestor. A dedicated team of engineers and scientists at a Kia research facility carefully designed each of the vehicles to function exactly as it does on the roadway. The same can be said for similar structures across various organisms. It gets worse for evolutionists, however, when genetics are brought into play. Just because two structures in different organisms look similar does not mean that they follow the same development path. In fact, some of them follow exact opposite developmental paths. This quirk of genetics is a huge problem, because the genes which code for the structure in question, such as an eye or a limb, do not contain the same information. If evolution’s explanation for homology were true, we would expect that these genes would either be the same, or extremely similar. Yet this is not what we find.
Structural homology does exist. There is no denying the similarities. Simply recognizing the similarities does not tell us why they exist, however. So why do we observe homology? Is it due to common ancestry as the evolutionists tell us? Based on the above paragraph, I think it’s pretty clear that common ancestry is not the answer. It is far easier to believe that animals have similar structures because they share a common Designer. But does homology even matter as evidence? The answer to that is effectively, not really. My late grandfather and I looked basically nothing alike, apart from sharing a gender and humanity. That did not change the fact I was related to him. A good friend of mine in college and I were frequently mistaken for one another because we were similar in build, height, and appearance. That did not make us related. A similarity of appearance, internal or external, does not equal relationship. That is determined by genetics. Studying homology merely results in linking creatures based on their superficial appearance, rather than the information that makes them what they are. Homology fails as evidence for evolution.