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Flashcards in Evolution And Selection Deck (8)
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1

What is meant by the term evolution?

Change of the average phenotype.

2

What is speciation?

When the organisms with the altered phenotype are unable to reproduce successfully with the initial population.

3

Define genetic drift.

Changes in allele frequency not due to natural selection but due to chance.

4

Define the founder effect.

A specific type of genetic drift which occurs when a small group colonises a new area and forms a new population. Because of chance the genetic diversity may be reduced compared to the original. Over time the reduction in genetic diversity and in different alleles can lead to genotypic and phenotypic differences between the new and old pop.

5

What are the 3 types of natural selection?

Stabilising
Directional
Disruptive

6

What is stabilising selection?

When the average phenotype provides a greater advantage than the extremes so they’re selected against. More individuals have the average value.

7

What is directional selection?

When an extreme is advantageous so is selected for and the phenotype changes

8

What is disruptive selection?

When the 2 extreme phenotypes are selected for because they both have advantages.