I was once, rightfully, criticized for writing a too self indulgent blog. So I feel I should, at times, take a tangent off to talk about actual science, before promptly returning to talking about myself. But I am actually talking about the science of my PhD, so I guess I am in a way indirectly talking about myself?
So the whole premise of my current PhD is looking at contemporary evolution. Evolution that happens over a short time period. "But Dan, Evolution takes millions of years!!" I hear most of you cry or "Evolution isn't real!" a alarming number of people might say, fortunately I don't know any of the latter and may they return to whatever bridge/rock they crawled out from under. To the former, those who like Darwin assumed that evolution is a lumbering leviathan taking a geological epoch to move from A to B, you are wrong. Plain and simple, wrong. I know, I spoke blaspheme about the great Darwin. He was many great things but greatness is not a constant beam of light, it flickers and wains from time to time and for the timescale of evolution it waned somewhat.
So if evolution is not a great lumbering beast, then what is it? Well to leap to Darwin's defense (and undermine my own argument) on some scales it is exceedingly slow. The evolution of theropod dinosaurs to what we now know as birds took millions of millions of years, but the change from the infamous Velociraptor to the humble woodpecker is quite a complex change, relatively speaking. Evolution of course doesn't have to be as complicated as the change of Dinosaurs to birds. Evolution is essentially just a genetic change, or a change that can be inherited. The simplest definition of evolution is "a change in allele frequency" (non biologists can gloss over that, or google it). It can be a genetic change that causes a slight change in a species's colour or a slight difference in leg size. It doesn't have to be a huge change, just one that can be inherited. And that, that can be seen over short time periods! A few hundred years, a hundred years, a few decades and even just a few years! If you have the right pressures and environment you will see evolutionary change in a short time period. Each year new cases of rapid evolution crop up. A well known example for anyone who has done Biology at school in the UK is the Peppered Moth which promptly evolved in response to the industrial revolution, producing more and more black winged individuals which were more camouflaged on the dark pollution covered trees, and back again when the air became cleaner in recent decades. There are many other examples across the globe, the Guppies of Trinidad for instance were the anvil on which most modern experimental evolutionary studies were forged, and of course the numerous studies of the Anole lizards in the Caribbean, which readily adapt their limb size to cope with a change in arboreal environment. So ultimately you want to know, can we see evolution over the course of my project? Potentially! There is definitely a possibility that we see an evolutionary response to the increased temperature of the islands we are moving the lizards too. But there are many other aspects we can focus on. So evolution doesn't just happen on a whim, there are driving forces that cause the change and evolution of species. These driving forces are natural selection (made infamous in the "Origin of Species") and sexual selection. Now I won't be touching on sexual selection for the most part so feel free to do your own ground work on that one, but I will be talking about Natural Selection a significant amount.
Natural selection is the driving force of evolution, evolution happens to a population but selection happens to the individual. An individual is "selected" to survive depending on how well suited it is to the environment. If it does survive it, potentially, gets to reproduce. if it gets to reproduce then it gets to pass on its genetic material. Say there is a population of 1 million mice and selection favours 500,000 of them. Then the genetic material of 500,000 mice is transferred to the next population, so even though selection acts on the individual scale this up and it can make a huge difference on the next generation, and the next and the next and so forth, eventually if you see genetic change then you have evolution (in a nutshell).
But how does selection work, what do I mean "selection favours"?
That is a story for another day... Part 2 coming up!