Evolutionary Mechanism

Question 1

Stabilizing selection

Answer 1

Trait that have allowed organisms to survive before continues to be the favoured trait

Question 2

Directional selection

Answer 2

Environmental change favours an extreme phenotype, leaving the middle old favoured trait unfavored

Question 3

Disruptive selection

Answer 3

Environmental change favours both extreme phenotypes leaving old middle favoured phenotype unfavored

Question 4

Sexual selection

Answer 4

Female chooses male who is stronger healthier and brighter in colour
Males compete for territory and access to females

Question 5

Recombination and independent assortment

Answer 5

Crossing over of alleles between chromosomes and random assortment during meiosis

Question 6

Mutation

Answer 6

Random changes in genetic code caused by errors in DNA replication

Question 7

Gene flow

Answer 7

Immigration new individual joining new population which brings new allele
Emigration organism leaves population and allele leaves

Question 8

Genetic drift

Answer 8

Bottle neck effect- natural disaster kills large number of species and small population left and doesn’t have the same allele frequency as before
Founder effect- organisms from large group leave to make new population and allele frequency will change depending on what allele founder brings