Exam 3 - Biology 1421
Key Terms for Chapter 15 - Life on Earth - Texas State University - Upchurch
Terms in this set (20)
a trait that helps an organism survive and reproduce
for any given gene, the relative proportion of each allele of that gene in a population
the evolution of adaptations in two species due to their extensive interactions with one another, such that each species acts as a major force of natural selection on the other
Two or more individual organisms of a single species (intraspecific competition) or two or more individuals of different species (interspecific competition) attempting to use the same scarce resources in the same ecosystem.
a pattern of natural selection that favors one extreme phenotype with the result that the average phenotype of a population changes in one direction. generally reduces overall genetic variation in a population.
Natural selection in which individuals on both extremes of a phenotypic range are favored over intermediate phenotypes.
a population in which allele frequencies and the distribution of genotypes do not change from generation to generation
The reproductive success of an individual organism relative to the average reproductive success of the population
Genetic drift that occurs when a few individuals become isolated from a larger population and form a new population whose gene pool composition is not reflective of that of the original population.
the movement of alleles from one population to another through the movement of individuals or gametes
All the genes, including all the different alleles for each gene, that are present in a population at any one time.
A change in the allele frequencies that occur in a small population purely bu chance.
a mathematical model proposing that, under certain conditions, the allele frequencies and genotype frequencies in a sexually reproducing population will remain constant over generations
a change in the base sequence of DNA in a gene; normally refers to a genetic change significant enough to alter the appearance or function of the organism
the process by which individuals that are better adapted to their environment are more likely to survive and reproduce than other members of the same species
a group of organisms of the same species that live in a specific geographical area found in the same time and actually or potentially interbreed.
form of genetic drift in which a population becomes extremely small; may lead to differences in allele frequencies and a loss in genetic variability
An interaction between species in which one species, the predator, eats the other, the prey.
form of natural selection in which individuals with certain inherited characteristics are more likely than other individuals to obtain mates
Natural selection that favors intermediate variants by acting against extreme phenotypes.