9. LAMARCK
Lamarck's Theory:
In the very beginning, giraffes had
got short neck and they used to
eat leaves from short trees. Then,
trees started to grow taller and
taller and giraffes couldn’t reach
the leaves, so that, they had to
stretch their necks to try to reach
them and eat. That is, giraffes
evolved from short to long necks
throughout time (history).
10.
11. Darwin's Theory: Long necked
and short necked giraffes once
existed together, but long-necked
giraffes had an adaptive
advantage.
DARWIN
12. Darwin's Theory:
Long necked giraffes and short
necked giraffes existed together,
but short necked giraffes
disappeared because they were
very hungry and they couldn’t reach
leaves from trees, so they died; and
long necked giraffes survived. This
is why we only see giraffes with
long necks nowadays.
DARWIN
14. DARWIN’S THEORY OF EVOLUTION
Animals change over time in order to survive where
they live. So, fish evolved to have gills because they
needed to be able to breathe underwater. Some
animals evolved to have sharp teeth or big claws so
they could kill their dinner. Other animals evolved with
scales or shells to protect themselves and not get
eaten as dinner. Others evolved to fly or climb to get
away from danger altogether. As people were evolving
from chimpanzees, we didn’t get any of those things.
Instead, we got really, really smart brains. And we survived because we used those
brains to think our way out of trouble. Plus, because we evolved to walk on 2 feet
instead of 4, we wound up with hands that, combined with our smart brains, allowed
us to do things like build houses, make clothing and weapons and — eventually —
invent really important stuff.
