This is the third instalment of my mini-series, “Creation, Evolution and Evangelicalism”. In this post, I intend to explain some of the evidence for us believing in evolution.
Now, this will probably be the second most contentious post in the series (the most contentious one being the theological post I intend to follow up with): I appreciate that many Creationists see the evidence I will present differently. After I posted up the first part of this series, someone on Twitter sent me a link to a book called “Should Christians Embrace Evolution?”, which is a response to the Denis Alexander book I mentioned I was reading. If you want a Creationist response to the arguments I have presented thus far, and here, I suggest reading that book. (Note that I haven’t read it as yet, I am planning to, but from the reviews I’ve read it seems that is a fair assessment.)
Part of the problem with scientific data is that I don’t have the expertise needed to evaluate it fairly. If on the one hand many scientists are saying “evolution is true because…” and on the other hand Creationists are saying “evolution is not true because…”, arguing over the science, because I don’t have the knowledge of biology I can’t determine which are necessarily true. All I can do is present some of the arguments, as explained by Denis Alexander, and claim this is the current ‘scientific consensus’.
Why look at the evidence?
Now I’m sure some people may be wondering why do we need to even look at the evidence for evolution? Surely the most important thing is the Bible: if the Bible says that we were created in six literal days, several thousand years ago, surely that’s enough for us! Why would we even need to look at the evidence?
Well, I believe it’s right to look at the evidence for evolution for a number of reasons:
- I believe that the Bible and nature were both written with the same hand. In other words, when all is fully known, there can be no conflict between them. Therefore, we have little to lose but much to gain by studying nature and how it works, including any evidence for evolution;
- I believe that some of it is relevant to Creationism (more on that later);
- It seems that our understanding of evolution has moved on a fair amount over the past few years. What I learnt in school was very basic – I remember hearing at the time that the evidence for evolution could fit on a pool table! But these days I think – especially in the field of genetics – this has evidence is much more conclusive.
So, all that said, let’s look at one or two examples. All I’m going to do here is to present a few of the examples from Denis Alexander’s book which I found particularly interesting – if you want a longer introduction read the book yourself, or I’m sure there are much better introductions to the evidence for evolution available! (If someone can recommend one, I’d be happy to link to it.)
Missing Links
One of the common criticisms of evolution I remember from my time as a Creationist was that of ‘missing links’. How can we know what evolved into what, given that there are no fossilised creatures discovered which can prove the evolution of one species into another? Well, in the last few decades it seems that there have been a number of discoveries which show more of these ‘missing links’ in the fossil record.
One such example is the Tiktaalik, found in Northern Canada in 2006 and dated at around 365 million years ago. This fossil fitted a gap in the tetrapod evolutionary sequence which would have been expected at around that time.
By the looks of it, the gaps in our knowledge fossil-wise are gradually being filled in.
Genetic Mutations
One thing I didn’t realise about our DNA is that our genes are not just similar to other creatures. A common fact is that we share 98% of our DNA with chimpanzees (not sure if the percentage is correct, but it’s a pretty high number). However, what seems to be the case is that our DNA is not just the same for the most part, but actually contains traces of genes which are inactive in us but active in other animals.
So, to illustrate that, human beings do not naturally produce Vitamin C (hence lots of old sailors suffering from scurvy on long voyages!). However, lots of other mammals do produce Vitamin C. Why is that? Apparently this is because of the gene gulo, which is present in rats but mutated and therefore disabled in humans.
I will shamelessly steal a table from Denis Alexander’s book to demonstrate:
| 80 | 90 | 100 | |
|---|---|---|---|
| Rat | GAGGTGCGCT | TCACCCGAGG | CGATCGACA |
| Human | GGGGTACGCT | TCACCTG_GA | CGATCGACA |
| Chimpanzee | GGGGTACGCT | TCACCTG_GA | CGATCGACA |
| Orangutan | GGGGTGCGCT | TCACCCA_GA | CGATCGACA |
| Macaque | GGGGTGCGCT | TCACCCA_AG | CGATCGACA |
This shows the nucleotide sequence in the part of the gene that has been mutated. As you can see, the primates all seem to be missing an “A” at position 97. The chances of this happening in all the primates are vanishingly small.
If this is indeed true, and we have interpreted the data correctly, I believe our only options are to believe that: 1. God created all the different species with that disabling mutation in some of them; 2. We evolved from a common ancestor and at some point that mutation occurred.
And apparently there is plenty more of this kind of evidence in our Pseudogenes – genes which we have which – as I understand it – are no longer active but serve merely to illustrate our genetic history. (As you can probably see, I am no biologist!) Such examples include Alu Insertion and Retroviral insertions (if you want to Google it; I’m not going to provide more info here).
Conclusion
This is probably the shortest (mostly stolen) overview of evolutionary science ever given. However, as I mentioned before, the reason I give it is because I was unaware before reading the book as to what the current state of evolutionary science was. It really seems like much work has been done, and it looks a whole lot more convincing to my eyes than it did in previous years.
The idea that our genetic code contains information which is no longer in use but simply shows remnants of our evolutionary past I find pretty mind-blowing. And, if it is indeed true, I believe causes more problems for Creationists: why would God create us with that code embedded within us?
Of course, there are counter-arguments you could make to that, and hopefully I will be able to get hold of the book I mentioned above and check those out. But for now I will leave it that the scientific consensus seems to be pointing in this direction; make of that what you will!
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