Macroevolution

Macroevolution refers to the large-scale evolutionary changes that occur over geologic time, including the origination, diversification, and extinction of species and lineages. It is contrasted with microevolution, which refers to smaller evolutionary changes within species or populations.

Overview

Macroevolution encompasses the grandest trends and transformations in evolution, such as the origin of mammals and the radiation of flowering plants. It also includes the most profound of evolutionary events, such as the Cambrian explosion, during which a great diversity of animal forms appeared in a geologically short period of time.

Mechanisms

The mechanisms of macroevolution include natural selection, genetic drift, mutation, and gene flow. These mechanisms can lead to the formation of new species (speciation) and the extinction of existing ones.

Evidence

Evidence for macroevolution comes from a variety of sources, including the fossil record, comparative anatomy, molecular biology, and biogeography. The fossil record, in particular, provides a chronicle of macroevolutionary events over the history of life on Earth.

Controversies

While the concept of macroevolution is widely accepted within the scientific community, it has been a subject of controversy in some public and educational contexts, particularly with regard to its teaching in schools.

See also

• Evolution
• Microevolution
• Speciation
• Extinction
• Evolutionary biology

External links

• Understanding Evolution: Macroevolution

Macroevolution Resources
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