Natural Selection and Evolution

Evolution

The book Why Evolution is True by Jerry Coyne presents a cogent case for evolution, a concept that can be controversial for some but accepted fact for others. This paper will work through the book -- the case that Coyne makes -- and offer reflections on my own journey of understanding the concept of evolution and its manifestation in the natural world.

Understanding Evolution

Evolution is not "fact," so much as a theory that is supported by a wealth of evidence. Just this alone lies at the heart of a lot of the misunderstanding about evolution. First proposed by Charles Darwin as a theory based on his observations of the natural world, evolution reflects the processes of adaptation that species go through, over time and successive generations. In adapting to their environments, species undergo changes that will, given enough time and dramatically different environments, result in the development of entirely new species.

The idea itself lacks controversy, in the sense that the theory of evolution is supported by a wealth of evidence, much of which is summarized by Coyne in this book. But the idea was controversial less for what it said than for what it meant. To the deeply religious, the Bible is the word of God and everything in the Bible is the truth, or must be, as the word of God. Evolution's argument inherently meant that the timeline for the development of this world was not as written in the Bible. The logic then is simply that if something contradicts the literal word of God, then that something is blasphemous, or worse. Essentially, people have often challenged the teachings of religion, or the ways in which religion has structured society, but evolution was supported by evidence, and rapidly adopted. This theory became a bigger threat to religion, to its power in society, not because it challenged the idea that the world is only a few thousand years old but because it challenged the idea of the Bible is the literal word of God. It would be right and reasonable to challenge other elements of the Bible if any one element was proven false.

For proponents of the theory of evolution, there is no particular dichotomy that must exist wherein evolution is either true or false, but for those who were threatened by what evolution symbolized, this is the case. Coyne sets out in his introductory chapter that he aims to show how evolution is right, and this has always been the approach of the scientific community, and a point of conflict between it and the religious community. The scientific community views evolution as something correct -- a theory built of observation for which evidence amassed since has held up. There is no contrast in this view -- evolution does not exist in opposite of anything. That framing, of evolution as opposite to something -- the word of God -- is one for religious people, and maybe the more aggressive atheists.

Evolution rests on a couple of key premises, which are introduced at the outset. Natural selection is the first. Natural selection refers to the process of species selecting desirable traits through reproduction. That species seek to reproduce with others of the species that are found desirable, and that the desirable traits tend to be those related to the ability to produce offspring with a better chance of survival. Those desirable traits, then, are bred in species.

We as humans have bred many species for particular traits. Every dog breed evolved from the wolf, yet they are very different from one another, and most are nothing like wolves at all. But breeding for traits has resulted in these different types of dogs with unique traits. Domestic animals and plants both are bred for specific traits, traits that for one reason or another are found to be desirable. We do the same with each other, too.

Another element of natural selection is survival, which is in the concept of survival of the fittest. In nature, survival until breeding age is by no means guaranteed. Indeed, the young of most species are vulnerable to disease and predation. They are not as strong as their mature counterparts, so have lower survival rates. A mature adult of many species is not vulnerable to predation at all -- but young and old are often. What this means is that those individuals of a species that survive to maturity are, in aggregate, those imbued with traits more geared to survival. They might be faster, or stronger, than their peers, and thus less likely to perish before reaching maturing. The strongest members of a species are more likely to survive and breed, which means that over time the traits that those members have are going to become more prominent in the species.

Time is another aspect of evolution. Evolution is a gradual process, one that takes place over successive generations. What is interesting is that for larger mammals it is very difficult to see this, because the time span between generations is lengthy. But scientists looking to test evolution have been able to show with smaller organisms that reproduce very quickly how traits can evolve. It often takes hundreds of generations to evolve specific traits, but this has been tested and shown to be true.

When Darwin traveled the world, one of the things he noticed was that animals in unique locations would evolve specific traits to those locations. So isolated islands like the Galapagos were a great place to understand evolution. If an iguana drifted to those islands by happenstance thousands of years ago, it was unlikely to inbreed with other iguanas, as there were none. The first time there were two iguanas there would have been the start of a new species. Those first two would have been of a different species, but their offspring, over successive generations and through the process of natural selection, would become very different from the original iguanas, adapted to their unique environments.

Other examples of this adaptation and natural selection mechanism can be found in species that evolved in areas where there were no natural predators. The kiwi is a ground bird in New Zealand, and it had no predators on those islands for most of its existence. When the Polynesians arrived, they brought chickens, pigs and dogs. A few hundred years later, Europeans arrived, with more dogs, and cats. The kiwi had never evolved defense mechanisms against such predators, and therefore was ill-equipped to deal with them. This stands in contrast to land birds elsewhere, which had evolved defenses -- ostriches are large and fast, for example, while grouse have limited flight allowing them to escape to trees.

Evidence

A large portion of the book is dedicated to building the case for evolution. The core concepts of the theory were described by Darwin, but the scientific process has been applied to each of those elements. What this means is that each element of the theory has been tested. People have sought to verify whether those assumptions have held up over time. The body of evidence has continued to grow, basically supporting all of the key elements of the theory of evolution. A theory, after all, is just a theory. It still has to be proven, and the more proof the better. In addition to directly observing evolution in species with short life spans, the body of fossil and bone evidence has also been used to test the different elements of the theory of evolution.

In some species, the skeletons show a pathway from one variant to another over a long period of time. Sometimes, there are gaps, but other times there are not. One chapter highlights that evolution is not something that happens as a one-time event, but is a process that continues to be ongoing. For example, human have vestigial tales, and there are many other examples of vestigial traits found in the natural world -- attributes that are being removed through evolution because they no longer serve a purpose.

Creatures that are poorly designed end up not lasting that long -- they are ill-equipped for survival. The fossil record is full of creatures that had a run, then died out. In many cases, their end was brought about by a change in the external environment. Climate conditions changed, their food sources died out, or they became a food source for a new predator. Whatever the case, some creatures evolved in a such a way that they were successful in one environment, but were not equipped to succeed when that environment changed.

Of course, evolution is not a process that is driven by any outside force. The point of the theory is that evolution is an ongoing process, and that it affects all species. There are only a few exceptions -- domesticated species -- but otherwise all creatures are affected. Indeed, even domestic species are affected. You now see cats with no hunting instinct whatsoever -- too many generations of captivity had bred that out of them. Evolution is something that happens, a consequence of choices made by individual members of each species, over a long period of time.

The choices that lead some members of a species to survive until maturity, and then the choices that govern their breeding habits, are ultimately what drives evolution. Traits that enhance survival of individual members are important, and members of species breed in part because ot those traits, but also just because of survival. Over time, these individual choices lead a species to emphasize specific survival traits. There are attractiveness traits as well, but for the most part in nature what is attractive is the possession of attributes beneficial for survival. This still happens, even with humans. The ones who are fit and capable of providing the means to raise a family are the ones most likely to do so. Humans incapable by way of physical or mental illness of raising a family are far less likely to have children.

Evolution and Design

One of the central tenets of evolution is that it is that there is no design. It is a process that is the result of millions of individual choices that contribute to the ability of creatures to survive to maturity, breed, and raise the next generation. The only motivation that creatures have is to survive and procreate -- the survival of the species drives all of these individual decisions as there is no thought process for these animals. This contrasts with the idea of intelligent design, which holds that God created the world and its creatures. The design of creatures by a supreme being is plausible enough if there are no limits placed on the capabilities of that supreme being. So the question then is asked -- is intelligent design incompatible with evolution?

It is only to the extent that it was created specifically to stand opposite the theory of evolution. Intelligent design was created as a juxtaposition, a means of arguing against evolution's random walk. Evolution is an unguided process, intelligent design argues for a guided process. But there is nothing in the theory of evolution that challenges, say, the existence of God. Indeed, if God created this world, then He created it as it is. That means billions of years old, with evolution being a part of that creation. That creation could even, in theory, be completely by His design. Staring down that potentiality -- that nothing in the scientific theory invalidates God or spiritual in any way -- is illuminating.

What is threatened is the structure of religion, and the power it has. One does not need to take every single word in the Bible as the truth to accept so much of its teachings. But instead of being adaptable, some religious groups have instead chosen not to adapt. They see a threat, and lash out against that threat, rather than evaluating whether that is ultimately the best course of action. What is interesting is that the response to the Origin of Species in the 19th century may well have been reasonable -- Darwin presented his body of evidence but much of it was not subject at the time to rigorous scientific verification. In other words, evolution was a strong theory, but not nearly as well-proven then as it is today. It was easier to reject or at least to question.

Today, the body of evidence supporting evolution is massive. Coyne outlines so many cases in the book, examples that support each and every key element in the theory of evolution. There is enough evidence that the case for evolution is no longer merely anecdotal or circumstantial, but verifiable. The core assumptions and arguments in the theory of evolution have been subjected to incredible rigor and still come out the same. The theory has been built bigger and stronger through this process of investigation, not rejected. Today, knowing this, it makes a lot less sense to dispute evolution. It is as close to fact as there is in this world. To dispute evolution in the face of the overwhelming evidence is an act of absurdity. Species survive specifically be recognizing the situation, and responding to it. If the situation has changed, then adaptation is required to ensure the long-run survival.

Ideas are not that much different than animals in this regard. Ideas need to be adaptable. That is one of the key ideas of the scientific method, that ideas are fluid. Today's idea, if disproven tomorrow, is rejected in favor of the better idea. Science does not cling to bad ideas, it is comfortable moving on from them, knowing that better ideas will always win out in the end. The rejection of evolution, knowing this, makes no sense. With the weight of evidence behind it, a strategy more fitting to the long-term survival of religious ideas would be to adapt them to what we today know as fact.

I once read a book by the Dalai Lama that stated something to this effect -- that even though Buddhist tradition has creation myths, those myths have been relegated to the status as cultural artefacts, now that we know the truth about the origins of the world and of life. The truths we know are not complete, but they are the best we have at this point in time. So, too, it is with evolution. There are religious traditions that have adapted to the level of scientific knowledge that we have now, and these traditions are operating from a position of strength. They are comfortable allowing people to critically evaluate scientific evidence. They know that this evidence only proves what it seeks to prove; by no means does it disprove the existence of God. Having the confidence to cede power over the people is something not everybody seems capable of doing, unfortunately.

Further Analysis

Religion really contains a couple of elements -- the spiritual/theological side and the social side. There is nothing in the theory of evolution that disproves the existence of God, just challenges the specific origin story of the world and humanity as presented in the Bible. That of itself should not diminish the power of the religion -- that power is dependent on people's faith and belief in God, not on the power of people to believe those specific stories. In other words, on a spiritual/theological level, religion and science are not incompatible.

It appears only on the social level that the two are incompatible. Coyne does seem to have written the book with this in mind. He seeks to put forth the scientific outlook that evolution is a theory on its own merits, not to be juxtaposed against anything. The reality is that it need not be so juxtaposed -- religion as s sociological construct derives tremendous power from faith, and that power is evidently threatened by the theory of evolution. Hence, the opposition to evolution from religious quarters is not theological but sociological, related to entrenched power structures in society. Coyne's best unstated argument is that the theory of evolution has to be understood on its own merits; to do this one must ignore the sociological debate about it, because that debate ultimately has nothing to do with the science or the theory itself. That debate is about power, sociology and religion's ability to influence people, not about nature and evolution. It is important for readers to realize that they can hold their religious beliefs and accept scientifically-verified reality at the same time; the idea that these ideas are mutually-exclusive is false, and human-created.