Gene Pools Flashcards
What is a gene pool?
The total number of alleles in a population
What is allele frequancy?
The number of people in a population with a certain allele
What is the Hardy-Weinberg equilibrium?
Measures the frequancy of alleles and genotypes in a population
p2+2pq+q2=1
What does p2 stand for in the Hardy-Weinberg equilibrium?
Frequancy of homozygus dominant in the population
What does 2pq stand for in the Hardy-Weinberg equilibrium?
Frequancy of heterozygus in the population
What does q2 stand for in the Hardy-Weinberg equilibrium?
Frequancy of homozygus recessive in the population
What conditions do we need for the Hardy-Weinberg equilibrium?
No mutations Random mating Large population Iscolated population No selection pressure
What is gene flow?
Migration of organisms or alleles in or out of a population so allele frequancies change
What is a population bottleneck?
Where an event reduces the size of the population so there’s a decrease in the gene pool and large chages in allele frequancy meaning a decrease in genetic diversity
What is the founder effect?
Loss of genetic variation when a small number of individuals become iscolated and form a new population with alleles not representitive of the original population
What is stabilising selection?
Natural selection conserving what is already present in the population. The frequancy of some alleles is high but others are greatly reduced
What is directional selection?
When an environmental pressure is applied to the population and there is a change in the allale frequancy in the population where the pressure selects for advantagous characteristics
What is disruptive selection?
Gives an increase in the diversity of a population rather than a trend in one direction
What is genetic drift?
Random changes in the gene pool of a population occuring by chance
