Aren’t epigenetic effects evidence for Lamarckism?
NOT REALLY. EPIGENETICS is
when genes alter their activity in response
to external factors such as diet, exercise
and chemical exposure. The sequence of
letters in the DNA doesn’t change, but the
DNA molecule acquires other chemical
changes that can be passed on to your
offspring. These inherited traits last for
two or three generations.
Lamarckism says the giraffe got its long
neck because parents stretched their own
necks slightly during their lifetimes and
passed that increase on to their children,
and so on. That’s quite different from the
Darwinian view that each generation has
a certain amount of natural variation, and
that giraffes with longer necks have more
offspring. Epigenetics is an important
influence on evolution, but it doesn’t
drive long-term species change.
Giraffes’ necks are an evolutionary puzzle