Chapter 16: Evidence of Evolution

Biogeography

Study of patterns in the geographic distribution of species and communities.

Catastrophism

Idea that catastrophic geologic events have periodically shaped Earth’s surface.

Comparative Morphology

Scientific study of similarities and differences in body plans.

Evolution

Chang ein a line of descent.

Lineage

Line of descent.

Adaptive Trait

A form of a heritable trait that enhances an individual’s fitness. An evolutionary adaptation.

Adaptation

Adaptive trait

Fitness

Degree of adaptation to an envornment, as measured by the individual’s relativegenetic contribution to future generations.

Natural Selection

Differential survival and reproduction of individuals of a population based on differences in shared, heritable traits.

Uniformitarianism 

Idea that gradual repetitive processes occuring over long time spans shaped Earth’s surface.

Fossil

Physical evidence of an organism that lived in the ancient past.

Gondwana

Supercontinent that existed before Pangea, more than 500 mmillion years ago.

Pangea

Supercontinent that began to form about 300 million years ago; broke up 100 million years later.

Plate Tectonics Theory

Theory that Earth’s outermost layer of rock is craked into plates, the slow movemnt of which conveys continents to new location s over geologic time.

Geologic Time Scale

Chronology of Earth’s history.

Half life

Characteristic time it takes for half of a quantity of a radioisotope to decay.

Radiometric dating

Method of estimating the age of a rock or a fossil by measuring the content and proportions of a radioisotope and its daughter elements.