Ch. 20-22 Flashcards
Phenotype
An observable trait such as human height or butterfly wing color
Species
A group of individuals that are capable, through reproduction, of sharing alleles with each other
Gene pool
All the alleles present in all of the individuals in a species
Population genetics
The study of genetic variation in natural populations
Population
Interbreeding groups of organisms of the same species living in the same geographical area
Somatic mutation
A mutation that occurs in somatic cells which are any cell of a living organism that is not a reproductive cell
Germ-line mutation
A mutation that occurs in eggs and sperm or in the cells that give rise to these reproductive cells and therefore is passed on to the next generation
Allele frequency
The proportion of a specified allele among all the alleles of a gene in a population
Evolution
A change in the genetic makeup of a population over time
Hardy-Weinberg equilibrium
A state in which allele and genotype frequencies do not change over time, implying the absence of evolutionary forces. It describes a situation in which evolution does not occur. And the absence of evolutionary forces, such as natural selection, allele and genotype frequencies do not change.
Genotype frequency
The proportion in a population of each genotype at a particular gene or set of genes
Fitness
A measure of the extent to which an individuals genotype is represented in the next generation
Modern synthesis
The current theory of evolution, which combines Darwin’s theory of natural selection and Mendelian genetics
Positive selection
Natural selection that increases the frequency of an advantageous allele
Negative selection
Natural selection that decreases the frequency of a deleterious allele
Balancing selection
Natural selection that acts to maintain two or more alleles of a given Gene in a population
Heterozygote advantage
A form of balancing selection in which the heterozygotes fitness is higher than that of either of the homozygotes, resulting in selection that ensures that both alleles remain in the population at intermediate frequencies
Vicariance
The geographical separation of a population, typically by a physical barrier such as a mountain range or river, resulting in a pair of closely related species
Allopatric
Occurring in separate non-overlapping geographical areas
Biological species concept (BSC)
Species are groups of actually or potentially interbreeding populations that are reproductively isolated from other such groups, cannot be applied to asexual organisms
Morphospecies concept
Members of the same species usually look alike
Ecological species concept (ESC)
The idea that there is a one-to-one correspondence between a species and its niche; example it is impossible for two species to coexist in the same location if their niches are too similar because competition between them will inevitably lead to the extinction of one
Phylogenic species concept (PSC)
Members of a species all share a common ancestry and a common fate
Peripatric speciation
A specific kind of allopatric speciation in which a few individuals from a mainland population disperse to a new location remote from the original population and evolve separately
