Friday, 4 November 2011

Evolution is the Greatest Show on Earth

Full disclosure: I didn't do biology past year 9 or 10, so please take my thinking within that context

The Greatest Show on Earth, by Professor Richard Dawkins is his defence of evolution. Unlike some other book he wrote where people said he was writing out of his field, this book is exactly his field. It is what he has been studying for much longer than I have been alive. I read this book as there seems to be some tension between some Christians and evolution and I think it is worth some time looking into the arguments. Before I went in reading this book I told a friend that I would be convinced of evolution if the following two issues I had could be explained:
  1. I would like some example of how DNA grows. If we all started off as a very "simple" life form with less genes than we do now, how do we get more genes? I get how when mixing DNA certain genes get turn on and off (say eye colour), but in order for them to be turned on and off there needs to be the room for that switch in the first place.
  2. Why did life have to come from one origin? I know it must be a complex thing for life to start, but were the conditions on our whole earth only suitable for to that one square millimetre where it arose? Why couldn't life have started the same way mould does on a piece of bread: in all sorts of different places?
I was already in agreement with adaptation and an old earth so I had no issues with the first half of this book. Dawkins pointed out how we selectively breed traits in flowers or dogs so that its offspring suit more of what we want. We put them in their own breading "island" so that they can not breed with others and introduce foreign genes into their pool. In the same way that we selectively breed traits in plants and animals, it also happens in nature, especially when an environmental change occurs. Some lizards from one island may end up on another and due to what food is available on this new island they might eat more plants and their stomachs may become more adapt at digesting this new food.

There was a really good E.Coli experiment, that I had only briefly heard about before, which Dawkins went into great detail. As I was reading about this and how he was going to reveal a great break through, I thought that this might solve my point 1 already and I would be pretty much on the evolutionist side. But the change that took place demonstrated how E.Coli adapted to cope with a limited diet and not that it grew another gene. All 59 of them had changed in the same direction, but there was no 60th one that grew. So I pressed on, as it was still early days in the book.

Dawkins went into a lot of explanation on how we date thing, which I only knew a part of. I was very impressed with how far back in time we can go with just tree rings and the whole field of dendrochronology. With the dating methods I was pretty much already on the same page, but now I think I understood the process even more.

There a chapter that went into great detail on how a normal embryo builds a new life form from local instructions and not from a top down approach. The method was quite amazing and complex with special enzymes and proteins that all have to work together in the right way, which are instructed by DNA on what to do next. But what I really wanted was an example on what goes on in evolution, when there is a mutation. What difference (if any) happens for one trait to be pushed in a certain direction or for more traits to grow. I still didn't get the evolving bit in the developmental stage of life.

When it came to arguing for new species, similarities in animals pointed to a common ancestor while also geographic or environmental change lead to the differences in animals. I found this first point more persuasive than the second. The common (mammalian) skeleton shared by people, monkeys, bats, dogs, horses (except for their feet) etc is the same skeleton, but different bones are different length. This is also the same for crustaceans like the lobster, prawn, crab etc. There are also some tubes in animals that seem ineffective or they take quite a long route to get to their point, such as the vas deferens in males and the laryngeal nerve (especially highlighted in the giraffe).

With environmental or geographical changes the idea that species got separated and turned into another species do not convinced me, mostly due to lack of micro detail. Species are those that can only mate between themselves and so I am willing to concede that both tigers and lions had the same ancestor for the reason they can mate between themselves (see ligers or tiglons), this is also true for zebras with horses and donkeys (see zebroids), and wolves, dogs and dingos. These animals were separated by great distances but they still can breed with each other. They may not want to in the wild as they are not attracted to them, but I wonder if this is the same with the iguana example in the book where the land ones don't mate with the water ones. It could be they are just racists towards their different iguana cousins.

There is much more in this book, and this is getting a bit too long, but I do have to say that it did make me pause to think about evolution and maybe brought me a few steps closer to holding it to be out right true. Maybe I am just too caught up with what I learnt in school with a basic (faulty?) understanding of genes and what Mendel got up to, that I am missing something in my understanding of biology (which is probably a understatement).

I do think it is possible for Christians to hold both Christianity and evolution to be true, but not in the sense that Dawkins was arguing for it. What also struck me about his book is that his world view comes with a bite and I found it a little unsettling. We are not designed by a creator, we are just like the animals. There is no ultimate reason or purpose for our existence and so I guess we can only subjectively make up our own reason and purpose (and that could well be to tell others there is no ultimate reason or purpose in life). Dawkins says even if we don't like the fact that it is true, we can not just reject this idea simply because we don't like it, which is right. But I think I am like Rich Suplita a university professor who became a Christian recently because he could not say that ultimately his daughters life had no ultimate meaning or purpose.

I should also say that I read this as an ebook off my phone screen, which in that format made looking at the footnotes hard. It also meant all the references to images on certain pages didn't fit and the images were a little small. Reading this off my phone convinced me that there is still some life left in the published book, but it is also easier to read a book off a back lit screen and to tap than to turn pages when you have a week old child in your arms at 1 in the morning.

Dawkins can make his main points very clear and writes at a popular level. I think the book could be about 25% shorter if he didn't go into so many digression. Maybe the extra stuff was for interest sake, or maybe to convince someone that he did know what he was taking about, but I think his audience wasn't aimed at the sceptic. He does say he wrote the book for the 40% of Americans that thought the world was young and didn't believe in evolution, but to people in that group they would only be offended by him. He calls them history deniers and questions their intelligence a fair bit. I know a few people who Dawkins is writing against, but I wouldn't recommend this book to them, as I don't think his tone would help, despite his years of experience in the field.


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