Natural Selection

Natural Selection

The title of Darwin's evolutionary biology book in 1859 was:

On the Origin of Species by Means of Natural Selection, or the Preservation of Favoured Races in the Struggle for Life

Natural Selection

Darwin suggested that Natural Selection is the mechanism of evolution.

Think. Pair. Share.

What is happening in this picture?

Natural Selection

Natural selection is the favouring of a trait that is best suited for survival in its environment.

Natural Selection

These traits arise from mutations.

(Is this real?)

Natural Selection

Many different traits within a species is called variation, and these variations are heritable.

Natural Selection

Depending on the environment, different traits from a variety of species are more viable.

Natural SelectionFor example:

•There is a population of mice living in a parking lot. Some are white and some are grey.

•When a predator flies over the parking lot, it will eat the first mouse it sees.

Natural SelectionFor example:

•Since the grey mice are more difficult to see on the concrete, white mice will be eaten more often than grey mice.

•Nature has selected the grey fur allele for survival in this case.

•The white fur allele may eventually die out in the parking lot population.

Natural Selection

Natural SelectionWhich of these mantises are most likely to survive?

... In this desert?

Natural SelectionWhich of these cows are most likely to survive?

... In this prairie?

Natural SelectionWhich of these butterflies are most likely to survive?

... In this forest?