00:01
Whales have very tiny fibones embedded in the skin next to their pelvis.
00:05
This is an example of fossilisation, genetic drift, a vestigial structure or an analogous structure.
00:13
So what do these mean? first of all, fossilisation.
00:16
This is the process in which a dead organism is preserved for a very long time.
00:22
So it's the preservation of organic matter.
00:26
And it might not be organic anymore.
00:28
Might have become mineralised, totally, but the structure is preserved.
00:34
Genetic drift.
00:36
So this is a potential cause of change in the population, evolution in the population, and it's down to random chance.
00:44
So even if you have an individual who is very genetically fit and you predict they can't have a lot of offspring, they could get struck by loon.
00:52
They can die just by bad luck.
00:54
Similarly, an unfit organism might get very, very lucky.
00:59
So genetic drift is taking all this probability into account.
01:03
So it's changes in the population due to chance...