Steve you have to take into account how long 100 million years really is and how widespread animal migration is without any intelligent aid and how incredibly widespread it was with pre-technological human intervention. With those factors taken into account I don’t think species spread would even be noticed in 100 million years time, and if it is it’s highly unlikely to be ascribed to intelligence and if it is then it’s doubly unlikely to be assigned to technological intelligence of our level.
The big thing to appreciate is that very few species leave any fossils at all and almost no individuals. It’s hard to get exact figures on how much evidence we don’t have since absence of evidence tends not to leave evidence. But I’ve seen figures saying that less than 1% of species leave a trace, almost certainly no more than 5% do. In terms of individual macroscopic organisms we are probably aware of only 1 in a thousand trillion. When you consider it that way it may well be that of all the rats for example that we have transported around the world only one individual will ever leave any trace that lasts 100 million years. It won’t be obvious that a rat fossil found in Hawaii is the same species as is found in Norway because no fossils will ever be found in what is now Norway.
What is more probable is that the descendents of the modern diaspora would come to the attention of future palaeontolgists. A rat fossil might be found in America dating from this current brief time period and a descendant from 500, 0000 years time found in France and the similarities noted. But that won’t be any more puzzling really then the fact that platyrrhine monkeys are found in South America 500, 000 years after they appear in Africa. Nobody sees that evidence and immediately assumes intelligent intervention. Instead the assumption is that the group spread by natural rafting, improbable though it may be. In the same way the presence of animals and plants of the same genera in South America and Australia aren’t explained by intelligent intervention but by models of continental drift and Antarctic land bridges. I really can’t see any reason why the same theories won’t simply be advanced for the seemingly odd distributions we have produced. Realistically the spread of cattle across the small gap between their natural range in Timor and their current location in Australia is no more improbable than the spread of monkeys between Africa and the Americas.
And the actual animals alive in 100 million years won’t show much evidence of their ancestry. They make provoke comment on the dispersal powers of some of the descendent groups but it won’ be obvious that one species gave rise to them. It will be equivalent to the fact that rodents naturally exists in Australia or cats in South America. Those groups have obviously moved along way form their point of origin but nobody finds that very odd because we assume that various groups have spread, not just one species. With 100 million years of evolutionary change behind them it will still be obvious that they are closely related but not obvious that they share a common ancestor at this date.
I guess the real point to note is that animal groups are known to have dispersed widely now and we don’t ascribe that dispersal to intelligent interventions. Instead we make up explanations of monkeys rafting across thousands of kilometres of open ocean or elephants swimming dozens of kilometres across open ocean or platypuses travelling via an unfrozen Arctic land bridge. Really none of those dispersals is any more dramatic than any dispersal of species that human have produced. For our effects to be apparent really would rely on ALL the species we’ve moved leaving a string fossil trace within the next 50, 000 years or so, something that’s highly unlikely to happen.
>>>> Well, assuming it was a massive nuclear war (enough that humanity became extinct) do you think many animals were survive?
It’s kind of hard to imagine how anuclear war could be so severe that all of humanity disappeared. Even with the worst nuclear winter scenarios, which now have little credibility, humanity wouldn’t vanish nor would a great many animals. The worst effects would be restricted the northern hemisphere for example.
Since it’s pure imagination as to how humanity died then it’s equally just imagination as to what animals survive. But ultimately it’s irrelevant. If animals vanish then there will be even less evidence of human assisted dispersal since it will rely entirely on those individuals over the past 500 years that have become fossilised and whose fossils are discovered. 500 years is a tiny period of time geologically speaking and realistically SFA are going to show up as fossils so we really won’t have much idea at all about distributions during that eyeblink period.
The aliens will discover a Mickey Mouse watch, and base their entire knowlege of our civilization on their interpretation of that object. (extra points if you can identify that story)
Just a thought, but what if an Earth had an intelligent civilization 100 million yrs ago? Would we have found evidence of it, with all our excavtions? Remeber the Sleestak from Land of the Lost? I know it’s a dum example, but what if their was a species of dinosaur that evoled the ablity to use tools and built, if not a technological civilization, but one at he level of the Greeks, Egyptians, or Azetecs?
PS Years ago the Discovery Channel did a special on possible evolution of life on Earth if manking were to die/leave. They did 5 million, 50 million, and 100 million years from now. By that last segmant sentiant descendants of squid were living in trees.
No real chance, and for the reasons already given. Without huge amounts of relatively recalcitrant and obviously manufactured trash becoming fossilised there’s no real chance of anything remianing. The continents themsleves have all moved since then. Land has been shaken by earthquakes, covered in lava and sunken into the sea. There just any large enough peices left to preserve the remains directly.
We’re left with indirect remains. Metal doesn’t fossilise very well since it corrodes rapidly in sediments. So that essentially leaves fossilised pottery, stone and wood. The chances of even that happening for anytyhing less than a worldspanning civilisation is highly remote. And if pottery shards were were found in anything but huge quantities in that era they would almost certainly be explained away as the cocoon of some creature or other or simply placed int he ‘unexplained’ basket as many fossils are. It would take something obviously technological to attract attention, and it’s hard to imagiune anything in a pretechnological era that fitts that description. Maybe a well crafted clay or stone figurine would be a give away. But the chances of such a hting survining are terribly remote.
Realistically we would be unlikely to know whether the dinsoasurs ever developed a civilisation.
In this incredibly hypothetical question, I need clarification on two points…
How long a time scale are we talking? A few hundred thousand years? A few million years?
How hard are the observers looking? Are they doing a planetary fly-by, or are they drilling core samples?
For one, there would be a helluva sudden change in the core samples as soon as we hit industrialization. And I think the markings of civilization (say, giant piles of twisted girders that used to be skyscrapers, the giant holes that were their foundations, massive long stretches of broken up rocky asphalt and concrete…
On your assumptions, absolutely aliens would be able to find humans were once on this planet. There just aren’t that many nukes on the planet now. And more importantly, they are selectively pointed. If the fallout killed all humans (for those who would argue it wouldn’t, let’s assume when WWIII happens bioweapons will also be used that will spread through the atmosphere killing all Africans, South Americans, etc.), there will be many large cities in Africa, etc. totally untouched by nuclear blasts. Just no way in 100,000,000 years all traces of these would vanish.
And, today humans can still find evidence dinosaurs were once on Earth. If we can find evidence of these creatures that built no cities, etc. then surely aliens looking carefully could discover man once lived on Earth.
There would still be the radio record, but that would be way the hell off in space and hard to pick out by then/there. There would likely still be deep space probes and the like, but they would be subject to the same issues. I think there would probably still be some metal artifacts/structures around, even if they were in horrible disrepair. As mentioned above, I think the big sign would be the mines, which would still remain in some form. But then, we know the dinosaurs were here, and they didn’t even leave a technological record.
Would there? The evidence for the KT impact is only barely detectable in core samples in s few places, and only then if you are specifically looking for it, and that’s only because it contains massive amounts of a rare element. It’s hard to imagine what might produce more drastic effects as a result of industrialisation. Carbon for example isn’t a rare element in our atmosphere and doesn’t last particularly well as a clear signal in sediments. So what exactly would the sudden change be that could be detected in any core sediment in 100 million years?
What evidence do you propose would exist of cities in 100 million years time? As Is aid earlier, go out and try to find any area of the Erath that has been stable enough to preserve structure for the past 100 million years. They just don’t exist. In that sort of time period there will have been subsidence, earthquakes, floods, volcanoes and meteor impacts on pretty much every square centimetre of the globe. So aside from fossilised cell phones what traces of a city might remain after even 1millon years, much less 100 million?
There’s little doubt that they will find evidence that humans once lived, but that isn’t the issue. The question is whether they will be aware that humans had civilisation. Yes, humans will leave fossils, but fossil humans isn’t in any way evidence of a civilisation. Most pf pour history we haven’t been civilised.
I have. There just isn’t any point in the fossil record where hundreds of thousands of species are confined to certain localities before Time X and spread all over the world after Time X (Time X being a point of time on the geologic-time scale). If there were such a point, I’d consider it fairly strong evidence for a prehuman technological civilization on Earth.
The original scenario was “what if all humans died”. I’d consider the mechanism of nuclear war to be secondary (it’s an unlikely mechanism for extinction – as others have noted, the human species would survive even if Western Civilization didn’t).
If the humans all died, the plants and animal populations established far from their homelands would (mostly) continue. The fossil record would not reflect the population that existed over a few centuries (trivial, as you correctly note), but rather from the time of the population transplant to the time of extinction from whatever cause (which could easily be millions of years).
To take the most obvious example, there would be thousands of types of Eurasian plants and animals suddenly showing up simultaneously in America and Australia. (A few of them would not show up – for instance, someone digging up fossil American horses would infer that they’d always been there: the 12,000 years of equine extinction would probably be indetectible after a hundred million years.)
Would not a single fossilized cell phone be proof of civilization? Such a thing can’t come about without civilization. Surely something of human landfills will still be around in 100 million years.
That’s quite correct rfgdxm, and I already pointed that out above. But a “a single fossilized cell phone” isn’t the incontrovertible trace of a city that you proposed would still exist. It’s certainly evidence of a technology but it could just as easily have come from a homestead or hippy commune as a city. I was specifically asking what evidence you believe would exist of cities.
The thing is steve that I don’t see any reason to assume that any such evidence will exist for the reason I’ve already given. Most species don’t; leave traces. If we have transported a million species around the globe than only 100, 000 will leave any fossil trace, and of that only 1000 will leave traves in more than two places. That’s not a huge number to account for. Yes, if every single transplanted species left a fossil record right now in all locations we would have something, but that won’t be the case. The majority of species leave no trace at all. There’s no reason that will be more true for feral emus than for T-rex.
That’s the point. There may well have been multiple times in the past here hundreds of thousands of species are confined to certain localities before Time X and spread all over the world after Time X but we have no knowledge of it. What we can say is that there were certainly a great many taxa confined to Africa for example that subsequently made there way North America and vice versa but we can’t say how fast that happened or how it happened simply because we haven’t the evidence.
For example we know that at one point horses existed only in North and Central America, then at some later point they exist in South Africa. We ant; say how that happened or even precisely when, simply that it happened. And somewhere in that same time period we have the dispersal of bison, cheetahs etc as well. Were intelligent lifeforms responsible? We can’t say but we assume not. It’s not the strong evidence you speak of. And that was just a few million years ago, not 100 million.
To you now it seems clear that species finding their way to Australia and America simultaneously is odd because you know of the existence of Wallace’s line. There won’t be any evidence at all of that line in 100, million years. Not a trace. So why wouldn’t the simplest explanation be a fall in sea levels leading to land bridges connecting all the major land masses? Future paleontologists may be able to postulate along period of isolation for those continents, semi-isoloation on the case of the North America, but after that all that will be evidenced is some degree of contact sufficient for horses to walk through.