Chapter 16 Evolution of populations Flashcards
(17 cards)
Gene pool
consists all genes, including all the different alleles that are represented in a population
Evolution in genetic terms
changes of allele frequency in a population, as the population is subject to the four main evolutionary processes: natural selection, genetic drift, mutation and gene flow.
Relative Frequency
The number of times that the allele occurs in a gene pool compared to the other alleles
What are two main sources of genetic variation
Mutations And genetic shuffling
single gene trait
traits that are determined by one by a single gene (two alleles)
Polygenic traits
Traits that are determined by multiple genes
Directional Selection
Graph moves one direction.
Stabilizing Selection
The growth is in favor of the average
Disruptive Selection
Favors less common. Graph becomes m shaped
Hardy Weinberg principle
States that allele frequencies in a population will remain constant unless one or more factors cause those frequencies to change
Five conditions required to maintain genetic equlibrium
Random mating Large population no Immigration Emigration No mutations No natural selections
Genetic Equilibrium
The situation in which allele frequencies remain constant
Speciation
formation of new species
How does speciation relate to reproductive isolation
As new species evolve, populations become reproductively isolated from each other
Behavioral Isolation
different courtship rituals or other reproductive strategy that involve behavior
Geographic Isolation
Two populations are separated by geographic barriers
temporal isolation
two or more species reproduce at different times
