4: GENETICS - GENETIC DIVERSITY Flashcards
1
Q
What is genetic diversity?
A
the no. of different alleles of genes in a species/population
2
Q
Why is genetic diversity important?
A
if a population has a low genetic diversity, it may not be able to adapt to a change in the environment and the whole population could be wiped out by a single event (eg: a disease)
3
Q
What is the difference between genetic diversity and genetic variation?
A
- genetic diversity is the no. of different alleles of genes in a species/population
- genetic variation is differences in alleles that lead to different phenotypes between individuals in a population
- genetic variation enables genetic diversity
4
Q
How is genetic diversity within a population increased?
A
- mutations in DNA forming new alleles
- different alleles being introduced into a population
5
Q
Why does genetic diversity allow natural selection to occur?
A
some characteristics are more advantageous than others
6
Q
What is a genetic bottleneck?
A
- an event that causes a big reduction in a population (eg: when a large no. of organisms in a population die before reproducing)
- this reduces the no. of diff alleles in the gene pool and decreases genetic diversity
- survivors reproduce and a larger population is made from a few individuals
7
Q
What is the founder effect?
A
- describes what happens when a few organisms from a population start a new colony and there are only a small no. of different alleles in the gene pool
- the frequency of each allele in the new colony might be very different to the frequency of those alleles in the original population (eg: an allele that was rare in the original population might be more common in the new colony)
- this may result in a higher incidence of genetic diseases
8
Q
Why does the founder effect occur?
A
- as a result of migration leading to geographical separation
- separation of a colony from the original population for other reasons (eg: religion)
