Genetics Evolution Mechanics Flashcards
What is evolution?
The change in genetic composition over time.
What is evolutionary theory?
The physical genetic changes and how they occur; the past shows the mechanisms of evolutionary change.
What are the 3 main ideas of evolution?
- Species change over time.
- Descent with modification (speciation or divergence genetics).
- Natural Selection (Survival and reproduction of individuals based on variation in individual traits).
What are phenotypes?
The physical expression of an organism’s genes (eye structure).
What is a character?
A specific feature of a phenotype (eye color).
What is a trait?
A specific form of a character (brown eyes).
What is a heritable trait?
A trait that is at least partially determined by genes (that which can be passed from generation to generation).
What is a genotype?
The genetic makeup of a gene (Protein sequencing).
What is an allele?
A specific version of a gene (like Mac vs. PC).
What is a locus?
A specific point on a chromosome where an allele exists.
What is the gene pool?
All of the alleles and loci that make up the variation within a population.
What is a population?
A group of individuals that interbreed within a geographical location.
What is a mutation?
A change in the nucleotide sequence of an organism’s DNA.
What is allele frequency?
How often an allele is seen in a population.
What is genotypic frequency?
The proportion of genotypes seen in a population.
What is artificial selection?
Human selection based on phenotypes.
What is adaptation?
A favored trait evolved through natural selection.
What is positive selection?
When a beneficial change is selected favorably.
What is purifying selection?
When a deleterious change is selected against.
What is gene flow?
A change in the allele frequency of a population.
What is genetic drift?
A random change in the allele frequency from generation to generation.
What is a population bottleneck?
A mass death event that causes genetic diversity to plummet.
What is the founder effect?
Where a new population colonizes an area. Lower genetic diversity results.
What is sexual selection?
When one sex non-randomly chooses a mate of the opposite sex.
What is a fixed allele frequency?
When a gene becomes monomorphic and has only one type of allele (frequency = 1).
What is genetic structure?
The frequency of alleles plus the frequency of genotypes.
What are the conditions of Hardy-Weinberg Equilibrium?
- No genotypic selection.
- No gene flow.
- Unlimited population size.
- Random mating.
- No mutations occur.
What is fitness?
How much a phenotype contributes to the next generation compared to other phenotypes of the same trait.
What is stabilizing selection?
Favoring the average characteristic of a population.
What is directional selection?
Favoring one direction from the mean, moving the mean left or right (extremes).
What is disruptive selection?
Favoring extremes in a population, but not the average expression.
