Chapter 11 Flashcards
All of the alleles in all the individuals that make up a population
Gene pool
How often a form of a gene appears in a gene pool(percentage)
Allele frequency
Many traits exhibit the intermediate phenotype; function where the graph does a bell shaped curve since most organisms exhibit the mean phenotype
Normal distribution
Change in allele frequencies in a population over generations; happens on a small scale
Micro evolution
Occurs when natural selection favors one of the extreme variations of a trait
Directional selection
Natural selection that favors intermediate variation of a phenotype
Stabilizing selection
Conditions favor individuals at both extremes of a phenotype
Disruptive selection
Movement of alleles into or out of a population due to or from the population
Gene flow
A change in allele frequencies of gene pool of a population due to chance
Genetic drift
Genetic drift that occurs after an event greatly reduces the size of a population
Bottleneck effect
Genetic drift that occurs after a small number of individuals colonize a new area
Founder effect
Form of reproduction isolation in which two populations are deprecated physically but geographic barriers such as rivers, mountains, or stretches of water
Geographic isolation
Condition that occurs when the frequency of alleles in a particular gene pool remain constant over time; population so not evolving; also known as genetic equilibrium
Hardy Weinberg equilibrium
Pattern of evolution in which long stable periods are interrupted by brief periods of more rapid change
Punctuated equilibrium
The ride of a new species from one existing species
Speciation
form of reproductive isolation in which two populations have differences in courtship rituals or other types of mating rituals that prevent them from interbreeding
Behavioral isolation
Form of reproductive isolation in which two populations have different mating season or mate at different times of the day
Temporal isolation
Process by which UNRELATED organisms independently evolve similarities when adapting to similar environments; also known as repeatable evolution
Convergent evolution
When two or more species sharing a common ancestor become more different over time; normal pathway of speciation seen in darwins tree of life
Divergent evolution
Process by which two species evolve in response to changes in each other; ex: plants and their pollinators
Coevolution
A term that typically describes a species that no longer has any known living individuals
Extinction
An evolutionary pattern in which many species evolve from a single ancestral species; ex: when dinosaurs became extinct small mammals are said to have done this
Adaptive radiation
What is the formula for allele frequency?
times allele is present in gene pool/total # of alleles for trait in gene pool
Genetic variation in a population (increases/decreases) chance for survival
Increases
