Biology Flashcards
Genotype
particular combination of alleles
Phenotype
physical, physiological, and behavioral characteristics
What does natural selection rely on?
An organisms traits
In what format should allele frequency be shown?
Percentage
What is allele frequency?
the number of times an allele occurs in a gene pool, compared to the total number of alleles in that pool for the same gene
In a gene pool, what genes and alleles do you count?
All of them! You count all of the genes and their alleles no matter the allele combination
Three evolutionary mechanics that allow for genetic vatiation
- Mutation
- Genetic recombination
- Lateral gene transfer
Mutation
A change in a gene or chromosome.
Genetic recombination
The regrouping of genes in an offspring that results in a genetic makeup that is different from that of the parents.
lateral gene transfer
The transfer of genes from one species to another, common among bacteria and archaea.
What is a polygenic trait?
trait controlled by two or more genes
What is fitness?
ability to survive and reproduce
Natural selection on single gene traits
Changes allele frequencies of phenotypes
Natural selection on polygenic gene traits results in one of the following
- Directional Selection
directional selection
Form of natural selection in which the entire curve moves; occurs when individuals at one end of a distribution curve have higher fitness than individuals in the middle or at the other end of the curve
stabilizing selection
Natural selection that favors intermediate variants by acting against extreme phenotypes
disruptive selection
form of natural selection in which a single curve splits into two; occurs when individuals at the upper and lower ends of a distribution curve have higher fitness than individuals near the middle
Genetic drift
A change in the allele frequency of a population as a result of chance events rather than natural selection.
Founder effect
change in allele frequencies as a result of the migration of a small subgroup of a population
Hardy-Weinberg Principal
principle that allele frequencies in a population will remain constant unless one or more factors cause it to change.
