00:02
To answer this question, we need to remember that an individual does not evolve.
00:12
An entire population is what evolves.
00:22
In other words, all of the members of a species collectively is what we talk about evolving.
00:27
Because an individual can't evolve.
00:29
An individual can't decide that it wants a longer neck and just grow a longer neck.
00:33
What happens is a population evolves over its own.
00:39
Time due to the production of offspring and the pressure of the environment upon that.
01:07
So a selective pressure.
01:26
So for example, we have a population of draps and they have eaten all of the lower leaves off of trees, but there are still leaves up higher.
01:38
So the drafts with the longest necks are able to reach those leaves while those with the shorter necks are not.
01:43
So the ones with the shorter necks are going to die off and not reproduce.
01:47
They will not be passing on their trait for short necks to their offspring.
01:52
The ones with the longer necks will live to reproduce, and therefore, there are going to be more of the offspring that have longer necks because they get the traits from their parents.
02:02
And this is going to happen after several generations...