Speciation

Question 1

What is speciation?

Answer 1

The development of a new species from an existing species

Question 2

How can speciation occur?

Answer 2

When populations of the same species become reproductively isolated. This causes a change in allele frequency and a change in phenotypes, meaning that a species can no longer interbreed fertile offspring.

Question 3

Name the two ways species can become reproductively isolate

Answer 3

Allopatric speciation (geographically isolated)
Sympatric speciation

Question 4

What happens during allopatric speciation?

Answer 4

A population becomes geographically separated, so that they experience different conditions and different selection pressure. This causes different changes in the allele frequency.
Changes in allele frequency results in differences in gene pools and changes in phenotypic rations.
This change in species means they won’t be able to produce fertile offspring

Question 5

What happens during sympatric speciation?

Answer 5

Random mutations occur within a population. It changes a diploid into a polyploidy by increasing the number of chromosomes.
Polyploidy’s can’t reproduce sexually and instead asexually reproduce which causes a new species to develop

Question 6

What is reproductive isolation?

Answer 6

Changes in allele and phenotypic freuencies resulting in unsuccessful breeding.

Question 7

What changes result in reproductive isolation?

Answer 7

Seasonal: individuals from the same population develop different mating/flowering seasons
Mechanical: changes in genitalia
Behavioural: a group of individuals develop courtship rituals that aren’t attractive

Question 8

What is genetic drift?

Answer 8

When chance dictates whether an individual will survive, breed and pass on alleles. Has a large effect in small populations where change has a huge influence