Speciation/allopatric

Question 1

What is speciation

Answer 1

Speciation is formation of distinct species in course of evolution.

Question 2

What is allopatric speciation and what does it require

Answer 2

Allopatric speciation is where species are geographically isolated from one another, so populations become reproductively isolated.
Requires a physical, geographical barrier.

Question 3

What is a species

Answer 3

Species is a group of organisms with similar morphology, physiology and behaviour which can interbreed to produce fertile offspring

Question 4

What Gene flow

Answer 4

Gene flow is transfer of alleles from 1 population to another

Question 5

What are reproductively isolated species

Answer 5

Reproductively isolated species are species which can’t interbreed to produce fertile offspring.

Question 6

What is geographical isolation

Answer 6

Geographical isolation is when population is divided by a physical barrier e,g new mountain range or river changes course so populations can’t mix

Question 7

Why does isolation lead to genetic differences

Answer 7

Isolation leads to genetic differences because of :
Natural selection-different selection pressures on different populations leading to changes in allele frequency in each population.
Mutations accumulate- random mutations occur in both groups, but as there is no mixing of gene pools mutations become unique to separate populations.

Question 8

What is random genetic drift

Answer 8

Random genetic drift is random fluctuation in allele frequency in population

Question 9

What is genetic drift and when is effect greater

Answer 9

Genetic drift is in a population, randomly, some alleles are not passed on to the next generations which reduces allele frequency. Effect is greater in small populations

Question 10

How may 2 different species of flower have evolved from an ancestral species

Answer 10

Ancestral species may have become 2 different species when
Population becomes geographical isolated.
Mutations could lead to diversity in flowering times.
1 population becomes reproductive isolated and gene flow between 2 populations is restricted.
Each region has different selection pressures so plants adapt to region, certain alleles become advantageous.
Flowers survive and reproduce, overtime this changes allele frequencies and populations become increasingly genetically different