Thank you for the great question.
Correct! All living things are the result of
evolution by natural selection. This means
that all brains, whether human brains, dog brains,
or even ant brains, are also a result of
evolution by natural selection. That is, the
genes (DNA) that create brains in different
animals are successful at replicating themselves
because they help solve problems, like finding
food, that affect survival and reproduction. But
then what makes brains different from animal to
animal? What makes human brains so special that we
do things like build skyscrapers and write poetry?
Why don’t all animals have the sort of brain we do
if that brain is so great?
The answer is that different animals faced
different problems over the course of their
evolution. In response to these different
problems, natural selection built different
brains with different abilities that solve those
problems. Also, brains are really expensive
to have in terms of the fats they are made out of
and the amount of energy they consume. So natural
selection will avoid selecting for big complex
brains unless they really help the animal exploit
its environment. The lesson here is that evolution
does not “want” to create bigger brains, rather
evolution produces the brains needed to solve
the problems the particular animal has given its
way of life.
Human brains are no different. Our brains were
designed by natural selection to solve problems
that our ancestors faced, including finding
food, avoiding predators, helping your relatives
and friends, navigating the world, and
communicating with each other.
Also, many of our most amazing abilities
like writing and math and culture come about as
by-products of systems in the brain that were
designed for other solving problems we faced over
evolutionary time. We can explain
extraordinary powers of human thinking by studying
our evolutionary history, what problems we faced
in the last million years, and how the brain
evolved to solve them.
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