3.4.4 Genetic diversity and adaptation Flashcards
What is genetic diversity?
The total number of different alleles present within a population / species
What are the advantages of genetic diversity on a population?
The higher the diversity, the higher the chance for some of the population to be able to adapt to the new change in environment - allowing for natural selection ( some characteristics are more advantageous than others)
What factors could increase genetic diversity?
Meiosis (crossing over, independent segregation)
Random fertilisation and fertilisation between individuals
Mutations
Gene flow - Introducing new alleles into a population when individual from another population migrate into it and reproduce
What is a genetic bottleneck?
When an event causes a big reduction in population size which could reduce the allelic frequency (number of different alleles) in the gene pool which reduces genetic diversity
What is the founder effect?
When a few organisms from a population start a new colony by migrating to different areas, meaning that the initial gene pool have a lower genetic diversity.
However, as individuals produce offspring and pass on their alleles, their allelic frequency may now be different to the other separated groups
What could the founder effect be caused by?
Geographical separation
Religion (Humans)
What is the process of natural selection?
- Variation exists within a population
- Variation can be increased through new mutations which result in new alleles being produced
- Individuals with advantageous alleles will be more likely to survive to reproductive age as they are better able to obtain the resources they need
- These individuals are more likely to reproduce
- Advantageous allies are passed down to next generation by those individuals
- There’s is an increase in allelic frequency of the advantageous alleles from generation to generation
What is natural selection?
Organisms differ in their reproductive success
