A few things evolution is *not*

Filed under: — Bravus @ 4:35 pm
  1. Evolution is not ‘nature red in tooth and claw’. The idea that ‘survival of the fittest’ means the biggest, baddest critter on the block is the only one that survives is clearly wrong, since we also have delicate butterflies and beautiful birds and tropical fish and so on. There are many evolutionary ‘strategies’ (not a great term because it suggests intention – ‘niches’ is better), and being damn sexy is at least as important as being powerful. Um, then there are things like stone fish that are hideous (at least to our eyes, but maybe not to their mates) but survive in other ways. But the notion that evolution is about viciousness and conquest is a human projection that has no relation to the scientific theory.
  2. Evolution is not an inevitable process of progress toward higher and higher complexity. Certainly complexity has increased over time in general, but for example whales are descended from land mammals – their ancestors left the sea and lived on the land for a while, then gave it up as a bad joke and went back to sea… but whales still have vestigial hips. Some cave fish used to have eyes but lost them over time because they offered no survival advantage, and so on. There are also many evolutionary dead ends, where a strategy was tried and found unsuccessful, or the environment changed. The only processes operating are mutation and natural selection, together leading to adaptation. There is (arguably) no grand plan.

Another corollary of that is that a well-adapted organism has no pressure to change – something very like modern crocodiles, tuataras, coelacanths and a handful of other species were around during the time of the dinosaurs (which ended 65 million years ago), and are still thriving. No reason they shouldn’t be if they’re well adapted to their environments: there’s no inevitable progression.

  1. Having said that, evolution is not *necessarily* atheistic. There are many who believe God used the mechanisms of evolution to create the diversity and complexity of life, taking a variety of roles in the process. The Intelligent Design movement is a subset of evolutionary theory (whether its creationist supporters realise that or not – it still requires Element 4 below) in which God is assumed to have taken an active role. Theistic evolution adds a fifth element (hey, wasn’t that a movie? ;-)) – divine intervention.
  2. Humans are not seen as being ‘descended from monkeys (or apes)’ in evolutionary theory – rather, humans and modern apes such as the chimpanzee (which shares something like 97% of our DNA) are seen as being descended from a common ape-like ancestor.

Evolution for (smart) beginners

Filed under: — Bravus @ 4:31 pm

For evolution to take place and create new species you need four things:

  1. Inheritance of characteristics – genes that can be passed on (either sexual or asexual reproduction will work)
  2. Mutations – these are caused by things like chemicals and cosmic radiation damaging DNA. The vast majority will be harmful but a few will be helpful.
  3. Natural selection – the organisms better adapted to a particular ecological niche will pass on their genes slightly more successfully, either because they survive long enough to do so or because they’re so damn sexy1.
  4. Lots and lots of time – since most mutations are harmful, and even helpful mutations easily get lost, and since each mutation is only an infinitesimal step along the road to change, evolution requires vast amounts of time.
  5. Now, only the mutation step is random: selection means that evolution over all is not a random process.

    The next (largish) post will address some common misconceptions and outline what evolution is *not*.

    1. ‘Survival of the fittest’ is a particularly bad way to put it, since ‘fittest’ reduces to ‘survivor’, so it means ‘survival’ of the survivors’. That’s tautological, but the problem is with the words, not the concept – clearly the survivors do survive. But ‘survival of the fittest’ also misses the ‘damn sexy’ factor.