Answer 1:
That's a great question, but there's really no
"after evolution."Evolution is a change in the
proportion of gene varieties in a population.
These proportions can change constantly. Evolution
doesn't have a goal. The changes can happen by
chance or they can be driven by natural selection,
or even artificial selection. In almost
any population, some individuals have traits that
make them better at surviving and reproducing.
Those individuals leave more offspring, so there
are more copies of their genes in the next
generation. That's natural selection. The
helpful traits may be resistance to disease, being
a good parent, or anything else that make some
individual in a population leave more offspring
than other individuals in the same population.
You might think it would be easy to figure out
the direction of futurechanges. You could look at
a trend, like more members of a tree speciesbeing
a fast-growing type, and then predict that in the
future moretrees will grow faster. But maybe
fast-growing trees are weaker andthey blow down
before they make many seeds. In other words,
maybethere's a trade-off between growing fast and
living a long time. Ormaybe fast-growing trees
need more water. That's fine when the climateis
wet, but what if there are some bad drought years?
As theenvironment changes, what used to be a
benefit may now be a problem. Humans are
also subject to natural selection, but we may have
morecontrol over some things. For example, our
ancestors needed very goodeyesight to find
particular plants or hunt animals. People with
badeyesight probably didn't leave as many
children. Some groups of peoplestarted farming as
long as 10,000 years ago. Eyesight was less
criticalthen. Much later, people invented
eyeglasses, so even having very pooreyesight
wasn't much of a problem. There's some evidence
that ethnicgroups that have been using agriculture
longer have worse eyesight thanother groups, but
it doesn't necessarily mean that future
generationswill have worse eyesight. In the
future, we may also be able to directlygive people
genes that they need. That's a whole new and
fascinatingpossibility, but there are a lot of
scientific and ethical questionsabout
it. Some people think that certain traits
evolve because we need them orbecause we use
something. Scientists know that these ideas are
wrong.Just because the air is polluted, we will
not magically get genes thathelp our lungs deal
with the pollution. Just because you lift
weights,your strength will not magically get
passed to your children. Our genescan change
(mutate), but those changes are random, and most
will not begood changes. What do you think
humans will be like in the future? Do you think
weevolve as rapidly as bacteria? Can you think of
examples of how humanshave changed the
evolutionary trends of other species? (Hint:
thinkabout domesticated plants and
animals). Thanks for asking, |