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If the Aliens land-would they be like us- or different from us?
posted at 04:32 pm on 11-13-2009
If we ever shake hands with an intelligent alien- would said creature even have hands?
How different, or how like us would they be?
Even on an Earth-like planet would the end-product of evolution be us and the other life forms were familar with? Or could evolution, even on our own planet have taken different courses?
Obviously we cant run the required experiment- running the film of the Earth's history backward to its start, and then letting the five billion year history of earth unfold a second time to see how it ends.
But we can do the next best thing- there is a naturally occuring labratory for how life could evolve on seperate earth like planet- and it exists right on our own planet. The labratory is the continent of australia.
Australia became isolated from the rest of the planet's landmasses some 200 millin years ago. That is one third of the enitre time since the "cambrian explosion"- the moment when all multicelled plants and animals first appeared in the sea 600 million years ago.
So for one third of the whole history of larger than microbial life on earth australia was, in effect, a seperate planet from the Earth.
Its lifeforms evolved seperately. Thus the native flora and fauna of australia are in effect real life extraterrestrials.
Australia has the same ecologicl niches as other temperate to tropic lands. The question is did evolution fill the niches with organisms that were similiar to organisms that filled the same niches on the rest of the earth, or did it come up radically different looking animals to occupy the same niches?
The answer is yes! Both.
Australia is populated by creatures that are amazingly similar to unrelated animals on the rest of the planet that play similiar ecological roles. And it has creature who are the opposite- radically different from ecological equivalents in the rest of earths landmasses.
The thylacine, or tasmanian wolf, is a predator that run down its prey. It looks like a wolf or dog despite the fact that it is a marsupial, and no more akin to canine than is a possum.
So a thylacine is to a placental wolf what the alien characters on star Trek are to humans. Clingons and Romulans occupy the same ecological niche on thier respective planets as we do on Earth, and they outwardly has the same shape and superficially resemble us. But they not only are seperate species, but are totally unrelated organisms (wolves are closer to us than to tasmanian wolves).
So the tasmanian wolf is evidence that the human like aliens of startrek are not so far fetched.
On the other hand there is the niche of large high speed herbavors.
In africa, eurasia, and in the americas, that niche is occupied by the varied members of the ungulate family- hoofed animals with antlers: mooses, elks, deer, antelops, elands, etc. All variations on the same hoof-and-horn theme.
Australia also fills this niche with a large and similarly varied-but- basically-the-same-theme animals.
But that one theme is a VERY different theme from ungulates. It is the kangaroo and wallaby family of animals.
Kangaroos are the equivalent of deer but very different from deer.
They hop on two legs, do not have hooves, and do not sport horns.
Both groups need to constantly replace thier teeth, but the mechanics are very different.
So kangaroos are to deer what a million eyed blob of purple protoplasm spilling out of a flying saucer is to ahuman.
So if you look at the tasmanian wolf you would conclude that evolution would tend to produce the same end products over time.
Look at the kangaroo and contrast it with the deer and you would conclude the opposite- that evolution can take any number of roads with infinitely different end points.
So australia offer us strong but contraditory clues.
there is an intriguing sidebar.
There is a species of Kangaroo in New Guinea that lives exclusively in trees and has prehensile tails to grasp branches.
At some point in the past a normal species of ground dwelling kangaroos captilized on thier upright posture and hoping talents to take to the trees of the jungle. They evolved into this upright bipedal tree dweller.
Its almost the exact opposite of the road taken by another mammal. One that started out in the trees-became upright in the trees, and then came down to the ground and then learned to stay upright by walking bipedally.
That mammal is now flirting with space travel and wonders about space travel in reverse - can aliens travel to us.?
Maybe if the aliens land -who knows- they may be bipedal mammals like us - but NOT like us.
Maybe they keep their young in belly pouches, have long tails, and can leap 14 feet in a single bound.
Maybe Star Trek ought to be rewritten slightly!
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