Science fiction depicts many types of intelligent aliens. Often they are similar to humans, but with different, often bizarre, heads. However, most biologists believe that any aliens are unlikely to resemble humans at all. Life evolves due to the environmental conditions of the planet, and it is extremely unlikely that any other planet will have a geological and environmental history similar to Earth’s. With different conditions, intelligent life on those planets will take different forms compared to us humans.
But not all scientists agree with
that idea. Simon Morris, a paleo-biologist with Cambridge University’s Department
of Earth Sciences, believes, researchers that intelligent creatures similar to
humans likely exist on many other planets.
Morris cites the theory of
convergent evolution, which says intelligent species everywhere may evolve into
something much like us. “One can say with reasonable confidence that the
likelihood of something analogous to a human evolving is really pretty high.
And given the number of potential planets that we now have good reason to think
exist, even if the dice only come up the right way every 1 in 100 throws, that
still leads to a very large number of intelligences scattered around, that are
likely to be similar to us.”
As an example of this idea, Morris
says that flight independently evolved at least four different times on Earth,
in pterosaurs, birds, bats, and insects. Eyes, he says, evolved in different
species perhaps as many as 40 times.
Many scientists strongly disagree with
that idea. One of those is the late evolutionary biologist Stephen J Gould who
found this idea utterly ridiculous. He claims that if you re-ran evolution on
Earth, even given the same geological and environmental changes our planet
endured, the likelihood of getting humans just like us is vanishingly remote.
Since random environmental effects create random sets of genetic mutations,
there is almost no possibility of ending up at the same evolutionary point. And
imagining this evolution occurring on a distant planet with very different
conditions compared to Earth is foolish.
Most scientists agree with Gould.
And besides, if all intelligent life were just like, what a boring universe
this would be.
Each month, I write an astronomy-related column piece for
the Oklahoman newspaper. On the
following day, I post that same column to my blog page.
This is reprinted by permission from the Oklahoman and www.Oklahoman.com.
