Evolution - Adaptation

I want to first note that evolution is not sentient. It is just a process.


Put simply, evolution is the process by which organisms mutate, and adapt to their environment. Most people would agree with this simple definition of what evolution is all about, but there are many who conjure up some incompetent ideas about it.


One of the words in the above definition which I think causes some mis-beliefs is 'adapt'. When adapt is used, it is not used to describe a situation where evolution thinks, 'this animal will be better with some wings, I will make it have wings by mutating it'. It is instead used to describe a situation where an animal mutates in some way which is beneficial to surviving it's environment. For example, the Ganges River Dolphin developed better echolocation due to the murky waters it lives in (as the waters have become more polluted over time). That's not to say evolution thought, 'These dolphins will be better off with better echolocation senses', and then evolution mutates the gene in the dolphin responsible for echolocation. It is instead to say that a random mutation happened in the gene responsible for echolocation, and since the waters are murky, better echolocation is beneficial to surviving in it's environment, meaning such dolphins are more likely to survive, and hence more likely to breed a greater number of times and pass on those genes (long sentences are long). This is what is meant by 'adapt'. The fact that the waters are murky has no impact on what mutations happen. It only has an impact on which mutations survive (this is basically what natural selection is, but I will post about that another time).


Keeping with the Ganges River Dolphins, they also have really bad eyesight. A teacher at my school once said that this is because good eyesight is not longer needed in the polluted waters so evolution simply got rid of it. No. Just... just no. This would only be true if good eyesight posed a significant risk to the dolphins, so much so that dolphins with good eyesight would die younger than others. Evolution does not think, 'This dolphin does not need good eyesight anymore, so I will get rid of it', because evolution does not think. Instead, the better the echolocation is, the more brain area it needs. It is possible that the part of the brain which looks after echolocation took over the part of the brain which looks after sight, therefore impeding the sight. The loss of sight is a consequence of better echolocation, not a consequence of murkier waters. The reason why it took over the sight part of the brain may be because the sight area is right next to the echolocation area. However, I am no dolphin brain expert, and there seems to be no good information about the areas of a dolphin's brain on the internet, so don't hold me against that.