random evolution question

[madnak]

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most of the evolution posters on this thread are poorly educated even on primitive evol theories (evidence is i know a lot more than them).

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It's always a comfort to know we have a real expert to keep us in line.

[Duke]

I never know what to think of some people. Either they're laughing it up at home by annoying the internet, or they're retarded.

[vhawk01]

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I never know what to think of some people. Either they're laughing it up at home by annoying the internet, or they're retarded.

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Why can't they be both?

[Piers]

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How likely would it be for species similar to those currently existing on earth to exist again?

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Depends what you mean by similar. There are plenty of examples of convergent evolution. Still mustn’t forget what ever caused the imminent mass extinctions might still be around and prompting evolution through new channels. I assume that we are starting again from whatever single celled life forms were able to survive.

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And mainly, at what point would a species be classified as "intelligent life"?

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Pick you own definition, its really not that important; although the difference between intelligent and technological is significant.

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(basically at what point would we consider them essentially 2nd generation humans)

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WTF is a 2nd generation human? A new intelligent spices being formed would be en example of convergent evolution. You seem to be using the word human as a synonym for intelligent in some really confusing way, so I don’t understand the question.

[The Don]

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Of course. This has already happened once.

While there are still many theories about why the dinasaurs went extinct, it is still an irrefutable fact that there was mass extinction at some point. Maybe a meteor, maybe disease, maybe a giant volcano, but it killed almost everything except microorganisms. And evolution created what lives now.

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A better example would be the Permian/Triassic extinction event... much more devestating. Either way, life rebounded quickly because a lot of complex organisms (mammals, turtles, crocs, various fish, amphibians, and insects 65 millions years ago and mammal-like reptiles, various amphibians, fish and insects 225 million years ago) survived these events and their offspring formed the wide array of life in in the Jurassic/Cretaceous and what we see today. If an event happened that destroyed everything except bacteria then or even single celled organisms then things would certainly have taken a hell of a lot longer to come about.

I agree with madnak that if no life survived then it would be very likely to see life come about again on this planet.

[Gugel]

it would take a truly monsterous astronomical collision to destroy life on Earth. bacteria live as far as 2 miles under the surface of the Earth and in terms of mass, there is more life under the surface than above it.

[vhawk01]

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it would take a truly monsterous astronomical collision to destroy life on Earth. bacteria live as far as 2 miles under the surface of the Earth and in terms of mass, there is more life under the surface than above it.

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I bet God could do it in 3 days flat.

[Jiggymike]

If ALL life were to go extinct, I do not know if we could predict if life would rebegin/reevolve. No one is too sure how life first evolved and a lot of older theories don't hold as much water as they did maybe 10 years ago (primordial ooze, urea being formed from inorganic matter, etc.). Theoretically, if life were just abolished from the planet, I do not think it would evolve again in the current conditions but might once the planet heats up/cools down or whatever we foresee in the next billion years.

Let's say that life DOES occur again, however. Not long ago I went to a lecture about someone who described what life would be like on Mars if there were indeed Martians. Basically, he made some predictions based on constancies in life on our own planet. Things that have reevolved more than once include joints, skeletons and support structures, limbs for locomotion, and GENERAL forms of these things would probably reappear. However, other aspects would probably be so vastly different that we couldn't predict it. For instance, we all know that the reproductive and excretory system are combined in tetrapods. This is not some sort of "natural" state but just a coincidence that the creatures that eventually moved onto land had this system; they could easily be separate while other organ systems could have been combined. Its possible that totally unknown forms could evolve as well, things unlike anything seen today.

However, the odds against any organism that exists now reevolving from scratch is probably greater than the number of molecules in the universe, or some huge improbability like that. I don't really want to get onto intelligent life, though, as I havent' really thought about it before.

[siegfriedandroy]

sorry was not trying to impress you. you are in a different league. probably freakishly intellectual. still smarter than you, most likely. yes, i will wager a tenth of my (elevated) roll to play lestat at chess poker or basketball. he appears smart at times, but is no sklansky. pretty sure sklansky could not score 1590 or higher 75% of the time. not even in his prime. perhaps i underestimate

[Hoi Polloi]

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yes, evolution would start all over.

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Two misunderstandings here I think: 1) evolution would not have stopped so it cannot start all over; 2) evolution does not a have starting place and a direction or goal, so again the notion of starting "all over again" is meaningless.