I have a number of science literate friends who, while they are perfectly happy to accept that evolution is true, don’t know the real fundamental of what natural selection implies or how it was derived. This is not a criticism of them, as I have argued before, not all ‘argument from authority’ is invalid (in context) and indeed those arguing against something without understanding are not really helping the situation. However, it seemed like a fun challenge to try and explain the very fundamentals of evolution by natural selection and the evidence (or at least examples of it in action) in as few words as possible. Explanations of evolution tend to run to a line or two, or entire pages or even book chapters and there seemed to be a spot on the market for something in between. A couple of minutes reading that includes as much evidence, theory and explanation as possible but in a compact paragraph. It might well be of interest and of use to some, so here goes.
Evolution by natural selection is the process where, over numerous generations, organisms adapt to changing environments. The environment can mean climate, geography, competition from predators, prey, or others of the same species etc. Traits (like size, colour, stamina, resistance to diseases etc.) are inherited by offspring from their parents (you do after all, look like your parents, and they like their parents). However, changes also occur between generations, both from the mixing of genes through sex, or novel mutations (you don’t look exactly like your parents, or your siblings). Nature provides the selection of which genes are the most suited to keep the individual organisms alive and to prosper. If there is a heavy winter, those with more fat or thicker fur will be more likely to survive, if there is a drought, those best at retaining water will do best, if predators get faster, the fastest prey will most likely survive. Since traits are inherited, those animals which survive best or have the most young will be the ones to pass those traits onto their children. Over time then, certain traits (like thicker fur, or bigger bodies or longer legs) will become more common as the organism adapts to an ever changing world and the species as a whole evolves. This can be seen in the fossil record as organisms change over time (like the appearance of limbs and fingers in fish as they evolve into amphibians, or the change from five toes to three to one in fossil horses). This can be seen in the genes of organisms in the lab as they are forced through mutations and changes by scientists. This can be seen in the wild as pests evolve immunity to poisons or bight fish grow dull when new predators appear, or beaks change in finches to feed on different seeds during droughts. This all adds up to a convincing single picture as nature selects the best adapted individuals and they pass on their traits to their offspring and so over time the species adapts and evolves.
Well that’s a shade under 350 words. More than I had hoped, but less that I had feared and it does (I hope) combine the basics of the theory with easy to understand examples and real evidence, as well as avoiding jargon or complex terms. If I wanted to keep it really short, the latter 3/4 of the last sentence could be considered enough as it does give the very bare essentials. Still, I hope it does a decent job given the intended compaction of a hundred and fifty years of theory and research into a single long paragraph. I’d certainly welcome other efforts in the comments or on other blogs.