Evolution

Summary This book (as the title implies) is interested in the emergence of species, and now that we are talking about it, what are species to begin with? At the time, there were many very experienced naturalists who would disagree on whether a certain plant or animal belonged in species A as a variety or actually should be considered a distinct species. These disagreements arose due to the fact that no one had a clear theory as to how these differences arose and up to then we used internal and external structure to define species. If these structures diverged enough, we would separate them into species. They also used the concept of whether entity A could potentially breed with entity B. If not, then the two entities must not be in the same species. There were other methods used, but these two should suffice to show how difficulties in definition might arise. For example, the internal and external structure of sexed organisms may very greatly as in humans, but we obviously must be the same species, right?….. Actually, that might explain some things. As for mating, this brings its own difficulties (I’m on a roll), but strictly speaking, you can have two different species reproduce, like a grizzly bear and polar bear, and this happens quite often in the plant kingdom. On the other hand, you have many instances of creatures in the same species category that can’t reproduce inside their own species. Think Mastiff and Chihuahua. So these principles are by no means black and white. The prevalent view at the time was the belief that each species was created individually, with this view the categorization of species should be much more straight-forward than it is, but Darwin had other ideas. Using pigeons, due to their availability and the long history they have of human selection, he built an argument. He stated that if we had found the various varieties of pigeons in the wild, we would without a doubt classify them as different species. We only refrain from doing so because we happen to know in this case that all the varieties descended from rock pigeons. What if this same concept applied to the whole animal kingdom? What if instead of individually created species there was a single progenitor which has given rise to the magnificent variety we observe today? How far might these accumulated minute changes take us? ...

Summary Dawkins argues that the fundamental unit of natural selection is at a gene level. He then continues to build the world from single genes into what we see today, explaining why many different behaviors that are confusing at first, when examined from the “gene’s eye view” they start to make sense. If you have heard of Darwin, then odds are you’ve heard the phrase “survival of the fittest”, but the question that this statement raises is, survival of what? The fittest claw? The fittest lion? The fittest pride? The fittest species? Dawkins makes the case that what is surviving is the gene and for this to work he defines gene slightly different than a geneticist would. He says a gene is the smallest single or collection of chromosomal material that lasts enough generations to act as a unit of natural selection. An easily understandable example would be the gene for blue eyes. On the face of it this definition seems circular, by definition he can’t be wrong. Genes — segments of chromosomal material — are the smallest trait-carrying units we know of, so if natural selection exists, it must start there. One might be tempted to ask why he didn’t define genes as a group or single quark that exists together long enough to be a unit of natural selection, but he spends a fair bit of time expanding this definition into less of a tautology and more of a theory. One interesting question the comes up is if natural selection is at the gene level and logically therefore all genes are acting selfishly (anthropomorphizing to help us think about the situation), then why would they band together with competing genes to form flesh suits, or elm trees? To answer this he brings in the concepts of replicators and vehicles. Another term he uses throughout the book was survival machines, this was a clever choice as it applies to anything that is alive, plants, animals, etc. Dawkins says that genes are the replicators and survival machines are their vehicles. So since we are already anthropomorphizing, I don’t think it would be too much of a stretch to picture a chromosome behind the wheel of a car on a speeding highway trying not to die, the car in this case would anything from single celled amoeba, to a giraffe. When we come back to reality of course this does not work in this way, as a single gene has next to no control over where a bat is going, or over the next word I type. But Dawkins chooses to zoom in on the “next to nothing” influence, because if you put enough next to nothings together, you just might have something! ...

Keeping this review short, I really enjoyed this book. Full of very interesting points and theories, really helped to get a grasp on the story about what happened between big bang and man. Got way more acquainted with monkey sexual practices than I had expected. The things that I didn’t like was that on one hand we have the insistence (correctly I think) that evolution is blind and has no destination in mind, where on the other hand there was still the subtle presence of the idea of “evolving past something”. Most notably xenophobia, this struck me as inconsistent with the previously utilitarian view presented on the universe. The other thing that caused some mental friction was their approach to chimps learning language. This section felt like quite a stretch to me, as I think it misrepresented chimps’ linguistical abilities. In total, I still enjoyed this book quite a bit and it is worth a read if only to see the interesting overlaps between monkey culture and human culture.