If humans were gone.......

[Bettina]

As I was lying in bed, I thought of this....Lets say some scientific satellite experiment in space went wrong and sent a human killing pulse thru the planet earth which killed every single human on the planet. Not one was spared and humankind was 100% gone.

 

Now we have a planet that has oceans, blue skys, beautiful sunsets, trees, animals, plant life, etc, but no humans.

 

Since there are presently some 15 million to 100 million species on earth but only one species able to post this question, what do you think would be the chances of humans ever populating the planet again.

 

Bettina

[-Demosthenes-]

I'd like to get my hands on that Human-killing pulse...

 

The niche(s) we leave would be filled eventually, one way or another.

[Callipygous]

but more importantly... would all the nuclear plants overheat and explode and all the airplanes crash to the ground and all that jazz and basically destroy massive portions of the ecosystem?

 

id say the chances are slim to none. while a similar species may evolve from the monkeys to fill our niche, i dont think you could have an identical species come back up.

[AzurePhoenix]

Chances of new humans? Without a doubt the answer is; Zero, Zilch, Nil, Nada. Humans as we know them would certainly be gone for good, but I'm betting any civilization that comes from monkeys or apes (or gibbons) would be similar to ours in many respects, physically and socially. Far closer to our own than say if squirrels, keas or octopus proved to be the next great intelligence, simply because they're scary-close to us anyway.

[Dak]

i dunno... intelligence isnt the best survivability-charechteristic, but it is relatively good if you are by far the most intelligent species, so i can see another species evolving advanced intelligence... and the human body plan is quite groovy (opposeable thumbs go well with intelligence).

 

yeah, they wouldnt be humans, but i think theyed be fairly human-like.

 

or possibly rats. there are as many of them as us, theyre everywhere that we are, and theyre quite intelligent already. maybe rats would be the next intelligent species?

[Xavier]

It doesn't seem too unreasonable to suppose that chimpanzees have many of the alleles available in their gene pool that are needed to get to the bottom rung of the ladder to intelligence (same ones that humans used). Once they are on the ladder their development would accelerate through cultural development squeezing out any competitors - but who knows? perhaps the dolphins are already at that cusp of cultural intelligence, though without manipulatory appendages their technologial development is hard to envisage.

 

It has been suggested that the human body shape is optimal for our evolutionary niche - the right compromise between sensory organ location and sensitivity, manipulative appendages, mobility, respiratory and gastric capacity etc. - and was proposed for likely looks of an extraterrestrial and for extrapolations of the evolved shape of dinosaurs if the asteroid had missed

 

I'd say it's not at all unlikely that the next tenants of this biosphere would be hard to tell apart from the present incumbents from a mile away.

[coquina]

As I was lying in bed' date=' I thought of this....Lets say some scientific satellite experiment in space went wrong and sent a human killing pulse thru the planet earth which killed [b']every single human[/b] on the planet. Not one was spared and humankind was 100% gone.

 

Now we have a planet that has oceans, blue skys, beautiful sunsets, trees, animals, plant life, etc, but no humans.

 

Since there are presently some 15 million to 100 million species on earth but only one species able to post this question, what do you think would be the chances of humans ever populating the planet again.

 

Bettina

 

I'd put my money on the dophins taking over. Maybe they would enslave the octopi - The dolphins have superior intelligence, but no method of building - the octopi have limited intelligence and 8 arms.

[Callipygous]

I'd say it's not at all unlikely that the next tenants of this biosphere would be hard to tell apart from the present incumbents from a mile away.

 

id guess it would be more that you could see the similarities from up close but NOT from far away. octopus for example... they have the dexterity needed, but they dont look at all like us. dolphins have the intelligence, but dont look like us. im betting it would be some animal that has the right mix, like we do, but that their overall body shape would be completely different, but when you actually examine it all the similarities are there.

[zyncod]

I would say that it would be completely improbable that this planet ever hosts another sentient species. If you take a look at really successful traits, like wings, these traits have evolved independently multiple times. Sentience, however, has evolved only once - and as a result of opposable thumbs and the ability to manipulate one's environment. If you think about it, what use would something like an eagle have for intelligence? It would still have to hunt mice using its talons.

 

The only analogues we have for intelligence are other freakishly overevolved traits - like necks in giraffes. Once longer necks started evolving in the proto-giraffe, they kept getting longer in order to reach leaves that weren't eaten by shorter giraffes. Similarly, in hominids, ever-increasing intelligence allowed the more intelligent hominids to exploit ecological niches that were not exploited by others. However, over-evolved traits are as much of a liability as they are a benefit. Say that trees suddenly got shorter - the giraffes would die out as a result. Similarly, a less intelligent species might be able to adapt to the changing climate as a result of global warming. Do you really think that humans with nuclear weapons are going to survive the resulting famines and scarce resources as a result of global warming? Sentience is only another freakish over-evolved trait and not even that interesting, except to sentient species like us, the way the giraffe's neck and the peacock's tail might be interesting to giraffes and peacocks.

[Aardvark]

 

Since there are presently some 15 million to 100 million species on earth but only one species able to post this question' date=' what do you think would be the chances of humans ever populating the planet again.

 

Bettina[/quote']

 

The chance would be next to zero.

 

In all the billions of years of life on Earth humans have arisen just once, a freak atypical species.

 

I'm undecided as to whether human extinction would be a good or bad thing. What are your thoughts?

[Blackfin]

In all the billions of years of life on Earth humans have arisen just once, a freak atypical species.

 

Um, no, actually. H. neandertalis existed alongside H. sapiens just 35,000 years ago, and they were just as human as we are. We lucked out in being more flexible and adaptable, becoming the only extant members of Hominidae. That doesn't mean that other humans never existed. Neanderthals used tools and buried their dead, too - and showed obvious signs of sentient intelligence, regardless of whether they survived or not.

[Aardvark]

Um, no, actually. H. neandertalis existed alongside H. sapiens[/i'] just 35,000 years ago, and they were just as human as we are.

 

You're arguing at a tangent.

 

I never denied the humanity of Neanderthals. The fact remains that human only arose the once and are a biological freak, atypical species.

 

The probability of them arising again if they became extinct is next to nothing. Convergent evolution can be seen in many niches, but not in humanities niche.

[ydoaPs]

no it isn't tangental. if he didn't post it, i would have. there was a time when there was more than one intelligent hominid species on the earth. our ancestors just happened to be slightly better or perhaps just lucky. although, i did hear something about a prehistoric interspecies war. i think it was on discovery channel, though.

[5614]

1) A satelite explosion like that just aint possible!

 

2) If all humans died, how could we repopulate the world again!?!

Or are you saying we would start off as a single cell thingy again and then over millions/billions of years evolve again, in which case I'd say it's unlikely that humans would be identical to how they are now.

 

3) The chance of a specie [non-human] 'rising to power' in that scenario is just as likely as any animal challenging the human race now, the only difference is that we wouldn't be here, so they'd go unchallenged... no specie is challenging us or enslaving other specie, so why would they just because we aren't here!

 

[um, dunno why I said #3, I'm sure I read somewhere about animals rising to power]

[Bettina]

1) A satelite explosion like that just aint possible!

 

2) If all humans died' date=' how could we repopulate the world again!?!

Or are you saying we would start off as a single cell thingy again and then over millions/billions of years evolve again, in which case I'd say it's unlikely that humans would be identical to how they are now.

 

3) The chance of a specie [non-human'] 'rising to power' in that scenario is just as likely as any animal challenging the human race now, the only difference is that we wouldn't be here, so they'd go unchallenged... no specie is challenging us or enslaving other specie, so why would they just because we aren't here!

 

[um, dunno why I said #3, I'm sure I read somewhere about animals rising to power]

 

It was intended as a hypothetical question. A "what if" (my two favorite words) scenario.....

I also believe humans came from one lineage. A single mutation from a pair of apes. From that single mutation, others came, mutating into several species like Homo rudolfensis, Homo habilis, etc. Then, as time went on, all but one of these species died out. The one with the bigger brain survived.

 

Anyway, I wanted to know what the chances were for that happening again if some "magical pulse" wiped out all human life.

 

Another thought....There could be planets out there like ours....blue skys, atmosphere, water, animal and plant life......yet no human life evolved.

 

We were lucky I think......

 

Bettina

[AzurePhoenix]

Edit: sorry, got confused, compounded by computer error...

[Aardvark]

no it isn't tangental. if he didn't post it, i would have. there was a time when there was more than one intelligent hominid species on the earth. our ancestors just happened to be slightly better or perhaps just lucky..

 

It is tangental as i never denied the existence of the different sub species of humans such as Neanderthals.

 

The hominid family is a one off.

 

although, i did hear something about a prehistoric interspecies war. i think it was on discovery channel, though.

 

That sounds fairly unlikely. A stoneage world war?

[AzurePhoenix]

It is tangental as i never denied the existence of the different sub species of humans such as Neanderthals.

 

The hominid family is a one off.

It's semantics. Like Aard is saying, humans as a whole only ever evolved once from a single ancestor. Different forms evolved and diverged from that human ancestor, but human-form creatures never again evolved from a non-human ancestor. A similar form never evolved independently from an alternate ancestor, the way shrews and shrew-like marsupials evolved from different families.

[des]

If our physical form has its advantages, in terms of natural selection, wouldn't it be likely that those same traits should be selected for again? Whatever makes us most adaptable gives us an edge. Our planet apparently likes our bodies, mores the pity.

 

Here's something we're assuming, though, that perhaps we should not:

Are we, really, the most intelligent animal on the planet? Or simply the most manipulative? Perhaps whales, for instance, have a better understanding of the universe, and simply don't feel the need to flaunt it.

 

This is fun, guys! Excellent discussions.

It's my first time, so how am I doing so far?

[Mokele]

If our physical form has its advantages, in terms of natural selection, wouldn't it be likely that those same traits should be selected for again? Whatever makes us most adaptable gives us an edge.

 

Adaptation is defined by the environment, and is constrained by development (why kangaroos hop, for instance). In order for humans to "re-evolve", a vertebrate with similar genetic and ecological state to our ancestor would have to encounter more-or-less the same situations thoughout millions of years. As this is very unlikely, so is the re-occurence of the humanoid form.

 

Truly effective forms occur numerous times in distantly related species (the wings of birds and bats, the shapes of sharks and dolphins, the proboscis of a butterfly and the beak of a hummingbird). Human form has only evolved once. While that doesn't mean it's *bad*, that also means it's not exactly overwhelmingly useful in most situations.

 

Mokele

[des]

<<In order for humans to "re-evolve", a vertebrate with similar genetic and ecological state to our ancestor would have to encounter more-or-less the same situations thoughout millions of years.>>

 

Why is this so unlikely? It's the same planet. Given time, and environment enough to survive in, I think the descendants of chimpanzees would appear very much like us.

[Kygron]

Human form has only evolved once.

 

I think I've heard this three times now in this thread. Is it really that important? It may be true, but, what if we're simply the first? What if our form IS one of the better types, it just has some prerequisits that have only been met in the last few million years?

[Mokele]

Why is this so unlikely? It's the same planet. Given time, and environment enough to survive in, I think the descendants of chimpanzees would appear very much like us.

 

It's possible, but not probable. I'm not familiar enough with anthropoid evolution to know the current arguements of why we started walking upright, but whatever it was would have to re-occur, and the chimps would have to not solve this problem in another way (either by cognition or evolutionary alternatives). Basically, covergence occurs when similar life-forms solve similar problems. In order for a chimp to evolve into something like us, it would have to face similar problems, which, given the complexity of the environment, is unlikely.

 

However, it is considerably *more* likely that a chimp would than, say, a rat, or a lizard.

 

I think I've heard this three times now in this thread. Is it really that important? It may be true, but, what if we're simply the first? What if our form IS one of the better types, it just has some prerequisits that have only been met in the last few million years?

 

That's possible, yes, but our forms have only a few good traits (free hands, seeing over stuff), with a lot of bad ones (poor defense due to posture, inherently unstable posture, etc).

 

Lots of creatures have had the opportunity to evolve erect-backed bipedality, but only a few have (the others being cormorants, auks, and penguins) and only one (us) uses that posture as the primary one and during any serious locomotion where performance matters. Speaking strickly biomechanically, the human form is vastly inferior to most other animals. I would say that it's not an pure adaptation itself, but a result of our past history constraining our adaptive possibilities so that this was the best of a limited set of options.

 

Mokele

[Mayflower]

In all the billions of years of life on Earth humans have arisen just once' date=' a freak atypical species.

[/quote']

 

Does anyone else here see humans as the end result of a long evolutionary process over these billions of years, rather than some incredibly short momentary freakish occurance?

 

Like having legs. You say something like that is far too typical... but what about during the time when only one species had 'legs'? Wasn't it a freakish, atypical thing at the time?

[darkkazier]

i think we are just one step in the long evolutionary ladder. but if we were wiped out it might give another species the chance needed to evolve to our level of intelligence. Aren't dolphins pretty close as it is?