Variation - Gene Pool + Changes To Allels

Question 1

Gene pool

Answer 1

All possible alleles in all individual of a species
-stable environment = stable gene pool + allele frequency consistent
-unstable environment = changing gene pool

Question 2

Micro evolution

Answer 2

Deviations in alleles frequency within a gene pool leading to evolution

Types:
-Genetic drift = changes in allele frequency due to random events
-mutation
-natural selection

Question 3

2 types of genetic drift

Answer 3

Bottlenecking - significant decrease to population due to disaster = gene pool decrease variation - neutral those killed by chance - more likely to kill those with recessive phenotype as less in number

Founder effect - small population of a larger population leave to start elsewhere = decrease gene pool - but gene too similar

Question 4

Mode of natural selection

Answer 4

Observation of what type of gene is more advantageous to environment.

Stabilising selection - selective pressure favours average gene (birth weight) - bell shape curve

Directional selection - favours 1 extreme phenotype over average phenotype (giraffe neck ) - bell shape curve

Disruptive selection - average phenotype is selected against (changing beak in Darwin finches) - bimodal curve

Question 5

Mode of natural selection diagram

Answer 5

https://resource.download.wjec.co.uk/vtc/2020-21/el20-21_1-4/image-4-eng.jpg

Question 6

Diagram of bottle neck

Answer 6

https://resource.download.wjec.co.uk/vtc/2020-21/el20-21_1-4/image-6-eng.jpg

Question 7

Diagram of founder effect

Answer 7

https://resource.download.wjec.co.uk/vtc/2020-21/el20-21_1-4/image-5-eng.jpg