Bio Lecture Ch 21 vocab

• -a mechanism that produces changes in a species
• -the differential survival and reproduction of individuals in a population based on variation in their traits

works on strains with certain desirable traits by animal and plant breeders

a group of individuals of a single species that live and interbreed in a particular geographic area at the same time

both the processes by which characteristics that appear to be useful to their bearers evolve (the evolutionary mechanisms that produce them) and to the characteristics themselves.

a characteristic that is partly determined by the organisms genes.

different forms of a gene that may exist at a particular locus

the sum of all copies of all alleles at all loci found in a population

a principle that describes a model in which allele frequencies do not change across generations and genotype frequencies can be predicted from allele frequencies

random fluctuations in allele frequencies from one generations to another

movement of individuals into or out of a population, or reproductive contact with other populations

any change in the nucleotide sequences of an organism's DNA

a situation in a large population passes through a period in which only a small number of individuals survive

the result of a population bottleneck

the reproductive contributions of other phenotype to subsequent generations relative to the contribution of other phenotypes

preserves the average characteristics of a population by favoring average individuals

changes the characteristics of a population by favoring individuals that vary in one direction from the mean of the population

changes the characteristics of a population by favoring individuals that vary in both directions from the mean in both directions

an allele that does not affect the fitness of an organism

a phenomenon where a polymorphism depends on its frequency in a population

the gradual change in a phenotype across a geographic gradient

the fitness benefits must exceed the fitness costs it imposes