Cenozoic era (sēnəzō`ĭk, sĕn–), last major division of geologic time (see Geologic Timescale Geologic Timescale
Era Period Epoch Approximate duration

(millions of years)

Approximate number of years ago

(millions of years)

..... Click the link for more information. , table) lasting from 65 million years ago to the present. The Cenozoic is divided into the Tertiary (from 65 million years ago until 2 million years ago) and Quaternary (2 million years ago to the present) periods. Early in the Cenozoic, Greenland began to separate from Europe; Antarctica and Australia, and Africa and India also separated. The great Alpine-Himalayan mountain systems were formed; rifting with associated volcanic activity occurred in Africa, Europe, Asia, and Antarctica. In the late Cenozoic, the Cascade Range of volcanoes extended from southern British Columbia to N California, and represented a new volcanic arc superimposed on older structures. The volcanic arc is still periodically active today. Following the disturbances of the late Mesozoic era Mesozoic era (mĕz'əzō`ĭk) [Gr.
..... Click the link for more information. , the geography of North America had by the beginning of the Cenozoic attained substantially its present form. The only areas subjected to inundation by shallow marine waters were the Atlantic and Gulf coasts and a small area on the Pactific coast. Most of today's common plants and insects can be recognized in early Cenozoic fossils. Modern grasses appeared in the mid-Cenozoic. The animal life of the Cenozoic was dominated by mammals, which were most numerous in the Tertiary period Tertiary period (tûr`shēĕr'ē)
..... Click the link for more information. and declined, with the exception of a few specialized types, in the Quaternary period Quaternary period (kwətûr`nərē)
..... Click the link for more information. . Theories explaining the decline or extinction of mammals during the Pliocene Pliocene epoch (plī`əsēn), fifth epoch of the Cenozoic era of geologic time (see Geologic Timescale , table), from 5.
..... Click the link for more information. and Pleistocene Pleistocene epoch (plī`stəsēn), 6th epoch of the Cenozoic era of geologic time (see Geologic Timescale , table).
..... Click the link for more information. epochs of the quaternary have ranged from a change in climate to the predation of humans. Cenozoic land mammals were never as large as the Mesozoic dinosaurs, but many were larger than today's mammals, and included beavers that grew to lengths of more than 7 ft (2 m), sloths as large as elephants, and birds up to 7 ft (2 m) in height. Around one million years ago, the ancestors of Homo sapiens, or modern humans, became dominant. Early humans are thought to have evolved in Africa during the Miocene and were widespread and accomplished toolmakers by the beginning of the Pleistocene; theory states that H. sapiens evolved in Asia and moved to Europe c.50,000 years ago, developed a form of agriculture in the Middle East c.10,000 years ago, and started writing and building the first cities c.4,000 years ago. See also geology geology, science of the earth's history, composition, and structure, and the associated processes. It draws upon chemistry, biology, physics, astronomy, and mathematics (notably statistics) for support of its formulations.
..... Click the link for more information. .

Cenozoic Era

Third of the major eras of Earth history, and the interval of time during which the continents assumed their modern configurations and geographic positions. It was also the time when the Earth's flora and fauna evolved toward those of the present. The Cenozoic, from the Greek for “recent life,” began c. 65 million years ago and is divided into two periods, the Tertiary (65–1.8 million years ago) and the Quaternary (1.8 million years ago to the present).