Selection and Isolation Pg 17L

Species over time Animals evolve and can change Sometimes the change is so great, they no longer can reproduce with each other

Why it happens If we are successful at something, we keep doing it. Animals see this as a survival trait and want it to pass to their offspring Think about battle of the beaks, who was more successful? Did you want to be using the tool?

Things happen As populations evolve and begin to become a new species they slowly grow apart from original one Eventually they become isolated

Behavioral isolation Two species are compatible for mating but have different courtship rituals or behaviors

Geographical isolation A population becomes separated by the geography Over time they adapt to that habitat and can only mate with those of a similar habitat

Temporal Isolation Species can only mate during a given time of the season. T for time, two similar species mate at different times therefore they can mate only with own species

Traits for fitness Sometimes the environment can change and select a more fit trait Ex. Climate change, new species, extinction of another species

Directional Selection When individuals with one of the traits has higher fitness One of the traits = Good

Stabilizing Selection When individuals with a blended trait (center of the curve) have a higher fitness Center of curve Blended trait = Good

Disruptive Selection When individuals at both ends have higher fitness you need one trait or the other to be successful