extinction and fossils

macroevolution

large-scale evolutionary change occurring above the species level

adaptive radiation

when one or more species diverge into many species

the cambrian explosion

key transitions that led to larger animals, complex body parts, and exoskeletons

mass extinctions

global, broad range of organisms, rapid 

Permian-Triassic

largest mass extinction caused by volcanic activity and low oxygen levels

cladogenesis

evolution of new clades

anagenesis

evolution within lineages

gradualism

species change constantly in response to natural selection

stasis

a specie remains unchanged in the fossil record for millions of years