Compare and contrast the Darwin-Wallace mechanisms of natural selection and evolution with Lamarcks ...

In the case of Darwin-Wallaces ideas: In the population of ancestral giraffes there was some
natural variation; some of the animals had longer necks than others. Those with longer necks
could reach higher into trees and eat leaves that their competitors couldnt reach. These
longer-necked animals were more successful, so they survived and reproduced. Finally, after
many generations, the animals looked like modern giraffes.
In the case of Lamarcks ideas: During periods of drought, ancestral giraffes had to reach
higher in the trees for nourishment. This activity stretched the giraffes necks and they passed
this acquired characteristic directly to their progeny.