responsible for producing genetic combinations not found in earlier generations.

Unit of geological time during which a rock series is deposited.

source of new alleles in a population. also is a change in the DNA sequence of the gene

Collection of evolutionary mechanisms, behaviors and physiological processes critical for speciation.

stated that by comparing the remains of organisms from different rock formations

who studied organizing the layers based on their depth and composition.

who published the first laws of stratigraphy.

occurs when the groups of species are geographic neighbors where gene flows with reduced distances. There is an abrupt change in the environment over a geographic border and strong disruptive selection.

occurs when members of a population that initially occupy the same habitat within the same range diverge into two or more different species. It involves abrupt genetic changes that quickly lead to the reproductive isolation of a group of individuals.

occurs when some members of a population become geographically separated from the other members thereby preventing gene flow.

could match their ages, regardless of how far apart they were

Ernst Mayr classified it in two categories

Give under of EON

occurs when individuals move into or out of a population.

who classified the two categories pre and post zygotic

deals with all the characteristics of layered rocks; it includes the study of how these rocks relate to time.

those that act before fertilization

A long and distinct period of history with a particular feature or characteristic

those that act after fertilization.

Give under ERA

process through which populations of living organisms adapt and change.

when chance events cause changes in alleles frequency

During these spans of time specific systems of rocks were formed.

The largest intervals of geologic time and are hundreds of millions of years in duration.