used to refer to a species that has died out and has no living members

method of determining the age of a fossil by comparing its placement with that of fossils and other rock layers

a fossil that is used to compare the relative ages of fossils

method of determining the age of a sample from the amount of radioactive isotope to the non-radioactive isotope of the same element in a sample

length of time required of half of the radioactive Adams in a sample to decay

timeline used to represent earths history

major division of geologic time

division of geologic time into which areas are subdivided

geologic processes such as continental drift volcanoes and earthquakes resulting from plate movements

changes in anatomy and physiology ecology and behavior that take place in clades larger than a single species

extinction caused by slow and steady progress of natural selection

The evolution of a species by gradual accumulation of small genetic changes over long periods of time

pattern of evolution in which long stable Are interrupted by brief periods of more rapid change

process by which a single species or small group of species evolves into several different forms that live in different ways

process by which unrelated organisms independently evolve similarities when adapting to similar environments

theory that proposes that eukaryotic cells formed from a symbiotic relationship among several different prokaryotic cells