who published the first laws of stratigraphy.

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

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

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

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

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

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

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

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

process through which populations of living organisms adapt and change.

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

when chance events cause changes in alleles frequency

occurs when individuals move into or out of a population.

responsible for producing genetic combinations not found in earlier generations.

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

Ernst Mayr classified it in two categories

those that act before fertilization

those that act after fertilization.

who classified the two categories pre and post zygotic

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

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 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.

Give under of EON

Give under ERA