patterns of evolution mod 9 assess

macroevolution

evolutionary change above the species level; EX: origin of a new group of organisms through a series of speciation events, impact of mass extinctions on diversity of life and subsequent recovery

stasis

a period of evolutionary stability/equilibrium; little to no evolutionary change within a species

living fossil

a species that has not changed remarkably in form or function over millions of years

negative selection

the active removal of a trait/allele that negatively impacts the organism/population’s survival or reproductive success

punctuated equilibrium

in the fossil record, long periods of apparent stasis, in which a species undergoes little or no morphological change, interrupted by relatively brief periods of sudden change

extinction

the process of a species dying out

mass extinction

the elimination of a large number of species throughout Earth; the result of global environmental changes

speciation

an evolutionary process in which one species splits into 2+ species

species

a population or group of populations whose members have the potential to interbreed in nature and produce viable, fertile offspring, but do not produce viable, fertile offspring with members of other such groups

reproductive isolation

the existence of biological factors (barriers) that impede members of two species from producing viable, fertile offspring

descent with modification

evolutionary process where species change and diversify from a common ancestor over time

divergent evolution

a process where 2+ closely related species become dissimilar over time due to adaptation to different environments, selective pressures, etc.

homology

similarity in characteristics resulting from a shared ancestry

homologous structures

structures in different species that are similar because of common ancestry; may or may not have similar functions

comparative molecular biology

a field that analyzes and compares the molecular characteristics of different organisms to understand evolutionary relationships, gene function, and biological process; EX: DNA sequencing

adaptive radiation

period of evolutionary change in which groups of organisms form many new species whose adaptations allow them to fill different ecological roles in their communities

gradualism

the theory that evolutionary changes occur slowly over long periods of time rather than quickly

convergent evolution

the independent development of similar traits or features in unrelated or distantly related species

analogy

similarity between two species that is due to convergent evolution rather than to descent from a common ancestor with the same trait

analogous structures

structures in different species that are similar because of convergent evolution; may or may not have similar functions

molecular clock

a method for estimating the time required for a given amount of evolutionary change, based on the observation that some regions of genomes evolve at constant rates