Evolution and Specialization
Chapter 9
Gene Pool - All alleles of all genes of each individual in the population
Factors Changing Allele Frequencies in Populations
= Changing percentages of alleles are small events leading to evolution
Microevolution - When frequency of alleles in a population change
Mutation
= Randomly introduces new alleles into a population (Random change in
DNA/Genetic variation)
= Changes allele frequencies
= Most mutations are neutral
= If mutation is bad, usually gets deleted since the individual dies and doesn't pass it
on
Gene flow (Migration)
= Transfer of alleles from one population to another
= Migrating individuals may bring new alleles in a population (invasive species)
- Create genetic diversity
= May change allele frequencies in either one or both populations
, Non-random Mating
= Mate selection where certain phenotype is biased
- Phenotype ex: Physical and behavioral traits
- Males competing over females
= Can also be due to inbreeding
- Closely related individuals breed together
- Both share similar genotypes
- Increased frequency of homozygous genotypes
- Harmful recessive alleles become more common
- Ex: Self-fertilization
- Choose specific alleles/traits so that the entire population has those
traits (create new species)
Genetic Drift
= Frequencies of certain alleles are changed by chance alone (in small populations)
Smaller population = Less likely for parent gene pool to be reflected in the next
generation
Founder Effect
= Few individuals start a new isolated population
- Carry some alleles form the original population's gene pool (Dunno what
alleles the founders carry therefore the traits they carry are by chance)
- Lack of genetic diversity
- New alleles brought in (Allele frequency changes)
Bottleneck Effect
= Population almost extinct due to natural disaster/interference (rapid decrease in
population size)
Chapter 9
Gene Pool - All alleles of all genes of each individual in the population
Factors Changing Allele Frequencies in Populations
= Changing percentages of alleles are small events leading to evolution
Microevolution - When frequency of alleles in a population change
Mutation
= Randomly introduces new alleles into a population (Random change in
DNA/Genetic variation)
= Changes allele frequencies
= Most mutations are neutral
= If mutation is bad, usually gets deleted since the individual dies and doesn't pass it
on
Gene flow (Migration)
= Transfer of alleles from one population to another
= Migrating individuals may bring new alleles in a population (invasive species)
- Create genetic diversity
= May change allele frequencies in either one or both populations
, Non-random Mating
= Mate selection where certain phenotype is biased
- Phenotype ex: Physical and behavioral traits
- Males competing over females
= Can also be due to inbreeding
- Closely related individuals breed together
- Both share similar genotypes
- Increased frequency of homozygous genotypes
- Harmful recessive alleles become more common
- Ex: Self-fertilization
- Choose specific alleles/traits so that the entire population has those
traits (create new species)
Genetic Drift
= Frequencies of certain alleles are changed by chance alone (in small populations)
Smaller population = Less likely for parent gene pool to be reflected in the next
generation
Founder Effect
= Few individuals start a new isolated population
- Carry some alleles form the original population's gene pool (Dunno what
alleles the founders carry therefore the traits they carry are by chance)
- Lack of genetic diversity
- New alleles brought in (Allele frequency changes)
Bottleneck Effect
= Population almost extinct due to natural disaster/interference (rapid decrease in
population size)
