Unit #4 Evolution Flashcards
Gene pool
Members of a population interbreeding with one another that share a common group of genes.
Evolution
Any change in the frequency of alleles in a population over time.
Genetic variation is produced in 3 ways.
- Mutations
- Genetic recombination
- Lateral gene transfer
Mutations
A heritable change in the DNA sequence
Genetic Recombination
Crossing-over can produce genetic recombination.
Lateral Gene Transfer
When genes pass from one individual to another individual that is NOT a parent/offspring.
Single gene traits
A trait that is controlled by only one gene.
Polygenic traits
“poly”= means many; “genic” means genes- a trait that is controlled by more than 2 genes; many possible genotypes; a variety of phenotypes; I.e blood types.
Natural selection
Populations change over time because individuals who inherit traits best suited to their enironment leave more offspring that less suited individuals, leading to gradual, favorable changes in the population
Biogeography
The study of where organisms live now and where they and their ancestors lived in the past.
Convergent Evolution
Species living on DIFFERENT continents each descended from DIFFERENT ancestors, but living under similar ecological conditions and exposed to similar pressures of natural selection= more common features.
Divergent Evolution
Occurs when 2 or more related species or populations become more and more dissimilar over time.
- Response to living in different habitats
- Can result in new species
Speciation
The formation of a new species.
Species
A group of organisms that breed with one another and produce FERTILE offspring.
Process of Darwin’s Finches
- Founders Arrive
- Geographic Isolation
- Changes in gene pool
- Reproductive isolation
