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Re: A Question I've Always Had About Evolution.
Bernard Bartfeld (bab@gwis2.circ.gwu.edu)
24 Jan 1997 01:54:14 GMT
Ed Conrad (edconrad@sunlink.net) wrote:
: On Tue, 21 Jan 1997, Raistlin Majere <dkresch@execpc.com>
: wrote to alt.fan.publius, etc.:
: > William DeMaree (demaree@erols.com) wrote:
: >>
: >> A question I've always had about evolution is where are all
: >> the creatures that are between men and monkeys? If there
: >> are thousands of monkeys, and millions of humans, shouldn't
: >> there also be many creatures that are only part way through
: >> the evolutionary process (from ape to man). Shouldn't there
: >> be many degrees of creatures going from man to ape such
: >> that it is impossible to say: "that is a man, or that is an
: >> ape"? I admit I am fairly ignorant of many evolutionary
: >> teachings, so this may appear to be a very sophomoric
: >> question.
: >>
: >> Please forgive that and enlighten me.
: >>
: >> William
: _____
Hi William. Evolution does not imply that there needs to be
creatures "between men & monkeys." To fully explain why, I might need to
know what leads you to believe that evolution must lead to such creatures.
But I'll assume that you have the same misconception many other people
have and that I had before taking a few biology courses. Let me share
some of what I learned and then apply it to your question.
The theory of evolution does not imply that humans are descended
from modern day apes or monkeys. We are related to them because we all
are descended from a common ancestor. Through heredity, we share many of
the same characteristics such as hands with 5 fingers & opposable thumbs.
Because we are not as closely related to them as to other humans, we don't
share many characteristics, for example bipedalism.
So to answer your question, think about this: I stand about 6 feet
tall. My brother stands about 5 foot 9. If I believe in heredity should
I then wonder where are all the creatures in between my brother & me?
I.e., should I wonder where my brothers who stand 5 foot 10, 5 foot 10 &
1/2, 5 foot 10 & 3/4, etc? You see why that doesn't make sense, right?
That's exactly why it doesn't make sense to believe there should
be creatures between monkeys and humans. My brother has a greater chance
of looking like me than our cousins because we share more genes than we
share with our cousins. Monkeys look more like us than tigers do because
we share more genes with monkeys than with tigers. But the degrees of
similarity exist in steps, not in a slope. For a family this is
because it would take thousands of children to make the degrees of
differences between us become like a slope. For the world's species, it
would take infinite fecundity with infinite resources to induce such a
slope. There would have to be no natural selection for such a slope to
exist. Even then, species would have to be capable of interbreeding so
that mutations in one species could be shared with other species.
Another point: Chimpanzees are the most closely related species to
humans today. But it would be a mistake to think of them as an creature
that's in between us and the other apes. To see why, ask yourself if we
humans are in between chimps and the other apes. No, right? But why not?
Is it because evolution is a ladder with the bacertia on the bottom,
humans on top & chimps on the rung just below us? It's not true.
Evolution doesn't have a direction. We all are in the form we are in
because of adaption to environment. Chimps are adapted to their
environment and we are adapted to ours (though our brains have since given
us the opportunity to move out of the environment in which we evolved).
If the environment changes, say due to a nuclear war, it may turn out that
we are no longer suffiently adapted to our environment to survive. It's
said that cockaroaches might survive. Does that mean that cockaroaches
are the goal of evolution, or that they are above us in the evolutionary
ladder?
A chimp might be more closely related to us than a tiger, but
then, we are more closely related to the chimp than it is to the tiger.
Neither we nor the chimp is in-between anything.
An in-between creature might exist between us and our anscestors,
but as I explained, chimps are not our anscestors and none of the other
creatures alive today are our anscestors either.
There are a couple of other important factors that explain why the
differences between, say chimpanzees and us are so strong and why there
isn't even a small population that's half way between. Of course, the
first is that we can't breed with chimps. We can't blend our genes so we
can't create a series of creatures that range from us to chimps.
The second two are time and mutation. Once 2 sets of creatures
can't interbreed, the mutations that occur can't be shared. Over the
generations, these mutations build up and the two sets of creatures become
more and more different from their common ancestor and more and more
different from each other. So you get very dramatic differences, with no
in between creatures. The differences get more and more dramatic as more
generations pass.
The third is natural selection. Some variations that have
occurred no longer exist because they were unable to compete with other
creatures that ate the same food, or used the same resources.
I've done my best to give you the official explanation I learned
in college. William, I hope you or anyone else writes me or posts a reply
if anything I said doesn't make sense to you. I also hope that others who
know more than I will read our posts and correct any errors I made.
Finally, in answer to those who might object to my posting on
religious grounds, William asked how theories of evolution account for the
lack of creatures between humans & monkeys, so I gave an answer that
comports with evolution. Nothing I've said prevents there from being a
God who made the various species and who also made this world look exactly
as if the evolution is responsible for the variation between species. God
might do that to allow people to use free will to choose whether or not
they make a leap of faith. Even if evolution itself causes speciation,
that still doesn't prevent there from being a God who started the whole
thing and has been gently guiding it ever since. On the other hand, the
theory of evolution doesn't require God to exist. As always, you need
faith to believe in God, not science.
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