I got asked a question yesterday on Facebook on whether
evolution in bacteria and primates differs. The short answer is no.
The long answer is that the process of evolution itself is
so simple in a way that it really doesn’t matter what its object is, i.e. what
it operates on. It’s easier to understand this if you think about atoms. The
forces governing their behaviour are equal properties in different measures.
Mass is mass, whether it’s zero or one hundred units. The slight differences in
these properties can lead to huge noticeable differences in final products,
just look around.
Natural selection isn’t something that can change depending
on what it acts on, be it bacteria or primates. Natural selection is there, and
any difference in products is just that. Bacteria and primates are different
because of the different evolutionary paths their ancestors took, the different
environments and selection pressures that led to their present day evolution.
Another question was whether increasing complexity of
species was an inevitable result of evolution. I suppose this is a bit like the
question “Can you return a fried egg back to a raw egg?” According to our
current knowledge, the answer is no, we can’t undo the burning of an egg or
piece of paper. It’s hard to imagine evolution working backwards, because it’s
hard to imagine undoing evolution. The matter of fried egg can’t work its way
to become a raw egg, it’s an irreversible reaction. In a sense, ancient species
had the resources to evolve in certain ways, but that doesn’t mean the
subsequent versions of themselves necessarily have the potential to reverse it.
If anything, any further evolution that leads to a similarity to previous
species would not be a reversal, but merely a continuation of the same
evolutionary pathway. Strictly speaking, there is no reason why natural
selection on its own couldn’t lead to future species looking more like ancient
species rather than more recent past species on the same evolutionary pathway.
An example that springs to mind, although not on an
interspecific level, but on an intraspecific level (that is, within one
species), is one insect. This insect has switched its wings on and off
repeatedly over a long period of time, depending on its environment. Would you
call that backwards evolution? I wouldn’t. Evolution evolves one way,
regardless of similarity between past and future species. A bit like time.
Comments
Post a Comment
Comment...