We have an interesting example of evolution apparently going bonkers at the moment. There is a new species of crayfish that can clone itself.

LINK

There was an unusual mutation in a very usual species of crayfish (the crayfish come from Georgia but the mutation appears to have happened in Germany where they are kept as pets). Which is how evolution works. Evolution is random mutations, 99.99999% of which don't work.

This particular mutation, read the article for the details, basically means that every one of this new species is female... and that all of her eggs are automatically fertile and reproduce a new female... whose eggs are fertile.

One pet owner in Germany (what person keeps crayfish as pets?) had this unusual mutation occur and suddenly he had crayfish coming out of his ears. He gave the mutants to fellow crayfish collectors and eventually someone dumped the things into a lake since they were replicating like mad.

Surprise! It turns out they do just fine in the wild.

The Marble Crayfish, as this new species is called... and it has undergone speciation since it is no longer fertile with its parent breed... is spreading like wildfire in areas it has been introduced in.

Scientist say that in the short term its a remarkable biological adaption... but its doomed in the long run. Every crayfish of this species shares the exact same genes so should a disease arise that affects them... there will be no genetic variation to protect the species.

To go back to an earlier thread... the United States was settled comparatively easily by Europeans because the native population had diddly doo da exposure to the new and wonderful germs we brought over. Which caused something like 90% of their population to die off in a fairly short period of time. The ten percent that survived are those whose genetic variance allowed them to survive the diseases.

We see this in diseases today. Something like 15% of Northern Europeans are effectively immune to the AIDS virus and there is a growing population in Africa who share that immunity. Which is not to say you shouldn't practice safe sex folks. When in doubt, wrap it before you pack it.

Evolution does not care if you are a "better" species or not. It just happens. A given species, by sheer dumb luck, might evolve to be perfect for its niche and thrive for hundreds of thousands of years. Only to have something change its suddenly obsolete.

A few million years ago Alligators evolved to do just fine in their niche. They almost died out thanks to humans but with that pressure being relieved they are back to eating folk's pets. And Crocodilian species have evolved greatly over the eons.

If you remember the amazing race horse Secretariat it is believed that due to a mutation passed on from the race horse Eclipse he had a heart which was larger then normal horses but functioned perfectly (confirmed in the necropsy of his body). Compared to other horses he was... to use the phrase... "a tremendous machine".

A mutation does not care if it is beneficial or not. It does not care if it provides a short term or a long term benefit... or detriment. Evolution is that room full of monkeys hitting random keys on a typewriter often enough to produce the entire works of Shakespeare.