Is extinction permanent?

[claymore]

If humans became an extinct species within say the next thousand years and the planet was left to roll quietly on for millions of years.... home to all the other life that we share the earth with now, could it possibly happen that the human evolutionary process would start all over and see mankind once again become the dominant species?

[Tichfield]

The way evolution works almost anything is possible, but the reemergence of a particular species that has previously become extinct is very unlikely.

Your question presupposes that humans are the current dominant species. There are people who would disagree.

For example, humans rely on bacteria for their existence, but bacteria did, can and will, exist quite happily without humans, or indeed, any mammals.

[Loosehead]

In the past when the dominant species has been wiped out they have been replaced by something else, what you might call the "apprentice" dominant species. eg the evolutionary chain to Humans was kick started by the extinction of the dinosaurs. If Humans where sudenly made extinct, then evolution would proceed, probably with Chimps etc.

There was a documentary on a couple of years ago that speculated as to what stage the dinosaurs would have reached today had they not been made extinct. The conclusion was that there would be intelligent upright reptiles running the world where the human ancestors would be vole type creatures living in burrows.

[jno]

still, scientifically minded dinosaurs might try to recreate humans by cloning, I suppose.

[dundurn]

Even if chimps gave rise to a hairless, bipedal, talking descendant and even if it could walk down the street and pass for one of us - it still wouldn't be human, in the same way that a very large flightless pigeon wouldn't be a dodo. That's what makes extinctions so scary. Frozen embryos and Jurassic Park-type cloning apart, there's no way back. Convergent evolution can give rise to lookalikes - marsupial moles and Australian magpies are spookily like their old-world namesakes, but they aren't closely related.

[kwicky]

When the dinosaurs became extinct then much later chickens appeared on the scene. Both are related I believe.

[kwicky]

Here is some proof:

http://www.physorg.com/news2313.html

[wildwood]

It is as good as impossible for humans to redevelop as we are now. All species alter to the changing Earth or they become extinct.

Homo sapiens are only one of a dozen or so species among the 2million+ that have become a distinct species in the last million years, so we are a very recent evolutionary product. Other close relatives like the Neanderthal man could not adept quick enough and died out. I really don't think an evolutionary accident like humans with the ability to imagine will ever happen again.

Humans are a temporary evolutionary hitch and after we blow ourselves up taking all mammals with us, the insects will once again dominate the land.