• Question: with the evolution theory how come there are still gorillas and there have been for hundreds of yrs and have not evolved in that time because they are ihn threat. Also there is a bombardier beetle which fires out two liquids which when they touch it causes an explosion. So according to evolution their would be no bombardier beetle because evolution relies on random mutation and if the beetle was attacked then it would have to fire the liquid at the right time and the right distance away from them either the explosion was too close it would kill the beetle and too far and the predator would kill the beetle. So how come the beetle and gorillas are still alive and does this not disprove the evolution theory?

    Asked by hedleysmitht to Arttu, Ceri, James_M, Monica, Philip on 17 Jun 2011.
    • Photo: James M Monk

      James M Monk answered on 16 Jun 2011:

      Well I am not a biologist, but we can think about what is going on here. Evolution takes hundreds of thousands of years for even a small change, so we would not expect gorillas to change in a few hundred years. Gorillas are well adapted to the environment in which they live – there are few or no animals that can kill a gorilla (other than a human). The problem that gorillas have is that humans have risen to prominence in a few hundred years, and we are destroying the habitat in which they can live. If the changes to the landscape happened more slowly then gorillas would have a chance to adapt to it and eventually possibly even give rise to a new species. So very fast changes to the environment can cause a species to become extinct.

      I don’t know about the bombardier beetle, but it sounds like it has quite a complicated defence mechanism. It is indeed amazing that such complicated biological structures can evolve, but it is not at odds with evolution. Do you know if each of the liquids on their own would serve a useful function? There has also been a very long span of time during which evolution has occurred – the Earth is about 4500000000 years old, and life has been on the planet for most of that time. So that is plenty of time for complicated structures to evolve. The eye has evolved independently several times, for example.

    • Photo: Arttu Rajantie

      Arttu Rajantie answered on 17 Jun 2011:

      Gorillas and humans share the same ancestors, and they have both evolved since then to adapt to their environments. Gorillas are under threat, and if they do become extinct, that is an example of how evolution by natural selection works. Of course, we should do our best to stop than happening.

      I had not heard about the bombardier beetle before, but there are many animals that spit out liquids to deter predators, so it could have evolved from something like that.