Question: Do you have any proof for the theory of evolution?

Sue Carney answered on 19 Jun 2011:

Hi Weasel,

This is an interesting question. I’m not an expert in this area, but I’ll tell you what I know. As far as I can see it, there’s plenty of evidence supporting the theory of evolution.

(Before I give further details, I should add here that in forensic terms, evidence is different to proof. In my job, proof is absolute, whereas evidence might support a particular theory but isn’t necessarily conclusive. However in general, scientists might talk about proof and evidence interchangeably, so, I hope you don’t mind me interjecting with that point. It felt important to mention, but now I’ll carry on and tell you about the evidence for evolution that I can remember…)

I’m sure there are thousands of examples of evolutionary change in different creatures that Darwin observed while he was doing his research. I know he studied finches in particular and documented many different species that had evolved in isolation on the Galapagos islands. He noted with fascination that each had a feature that meant it was perfectly suited to its own particular habitat, for example beaks suited to particular types of food.

For some reason though, the example I remember most clearly is one learnt at school: The peppered moth. I confess having to google the name of the moth, but I remembered the rest of the story, which is something along these lines: The peppered moth lives on trees and used to commonly have a speckled appearance which meant it was perfectly camouflaged against the tree bark and the lichens growing on the trees. But, at some point, the industrial revolution happened and lots of the tree trunks were covered in soot and dirt from pollution produced by nearby factories which also killed off many of the lichens growing on the tree trunks. The speckled moth had lost its camouflage, was now easy to spot and many were picked off by predators. However, a few moths, that by chance had darker coloured wings had a better chance of survival, because they were better camouflaged against the soot-stained tree trunks. It was mostly those moths that had a chance to reproduce. Many of the offspring of the darker winged moths inherited the darker wings. They too stood a better chance of survival and had more chance to reproduce. Multiply that by a few generations of moths (and remember, a generation in moth terms isn’t that long at all) and we observed that the speckled variety of these moths were suddenly pretty rare creatures whilst the vast majority now had dark wings. Was that a coincidence or directly due to adaptation to a change in the environment? This is certainly evidence in support of the theory of evolution!

I hope this helps. 🙂