Biological Evolution

Question 1

How does genetic variation arise?

Answer 1

1) random fusion of gametes during fertilisation
2) random segregation and assortment of homologous chromosomes (m1a1) or non identical sister chromatids (m2a2)
3) crossing over between non-sister chromatids of a pair of homologous chromosomes
4) Gene and chromosomal mutation
5) environment influence, phenotype variation
6) migration from 1 population to another, introduce new alleles, increase variation within population along with random mating, promoting gene flow

Question 2

How is genetic variation preserved?

Answer 2

1) diploidy
2) neutral mutation
- not selected for or against, hence preserved in population
3) heterozygote advantage
- at selective advantage
- more lively to survive and reproduce