Chapter 19 Flashcards
Gene Pool
the total number of alleles for all the genes in the population
Tracing Evolution
can be done by studying genotypic frequencies over time in a population
Hardy Weinberg Principle
given five conditions allele frequencies within a population will remain constant in each generation
measures amount of genetic variation within a population
identify if the population is in genetic equilibrium or if microevolution is occurring
Hardy Weinberg Conditions
- very large population
- random mating within population
- no net mutation
- no migration
- no natural selection
Causes of Gene Pool Change
mutations gene flow non-random mating genetic drift founder effect the bottleneck effect natural selection Sexual selection heterozygote advantage
mutations
leads to new alleles or back mutation which is when a mutation is reversed
gene flow
migration of individuals moves new alleles to other populations
can increase diversity in near populations
reduces genetic differences btw populations
Non Random mating
selected individuals have a better chance of mating than others bc of certain phenotypes
Genetic Drift
affects small populations
Founder Effect
occurs when a new isolated population develops from a small number of individuals
rare alleles may become more common and others may be lost
The bottleneck effect
occurs when there is a rapid decrease in population size which leaves only a few individuals to pass on genes and leads to less genetic diversity
Natural Selection
organisms that survive pass on their genes which increases there allele frequencies
can be caused by selective and environmental pressure
Sexual Selection
non-random mating bc species with a particular trait are favoured
heterozygote advantage
individuals carrying both alleles have a better survival chance then homozygous individuals
habitat fragmentation
large continuous habitats are split due to humans which prevents gene flow btw populations
