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Torre Sant'Andrea
Ice age fauna of northern Spain - Mauricio Antón

Cenozoic Era

The Cenozoic Era is the current geological era, spanning from 66 million years ago to the present. It is the third and youngest era of the Phanerozoic Eon, following the Mesozoic Era. The Cenozoic is divided into three periods: the Paleogene, Neogene, and Quaternary; and further subdivided into epochs. The era is characterized by the significant development of mammals on land and in the oceans, as well as the diversification of birds, insects, and flowering plants.

Overview[edit | edit source]

The Cenozoic Era is often referred to as the "Age of Mammals" because it was during this time that mammals evolved to fill the niches left by the dinosaurs, which became extinct at the end of the Mesozoic Era. The climate of the Cenozoic has varied significantly, from the warm and humid conditions of the Paleogene to the ice ages of the Quaternary.

Paleogene Period[edit | edit source]

The Paleogene Period (66 to 23 million years ago) marks the beginning of the Cenozoic Era and is divided into the Paleocene, Eocene, and Oligocene epochs. This period witnessed the rapid evolution and diversification of mammals and birds. The climate during the Paleogene was generally warm, allowing for the widespread development of forests.

Neogene Period[edit | edit source]

The Neogene Period (23 to 2.6 million years ago) includes the Miocene and Pliocene epochs. During the Neogene, mammals and birds continued to evolve, and the first hominids appeared. The climate gradually cooled, leading to the establishment of grasslands and savannas.

Quaternary Period[edit | edit source]

The Quaternary Period (2.6 million years ago to the present) is divided into the Pleistocene and Holocene epochs. The Quaternary is known for its ice ages and the further evolution of humans. The period has seen significant climatic fluctuations that have influenced the distribution and evolution of life on Earth.

Climate and Geography[edit | edit source]

The Cenozoic era has experienced significant changes in climate and geography. The early Cenozoic was generally warmer than today, but a cooling trend over millions of years led to the ice ages of the Quaternary. The formation of mountain ranges, such as the Himalayas, and the opening and closing of ocean gateways, such as the Isthmus of Panama, have significantly influenced climate patterns and ocean currents.

Flora and Fauna[edit | edit source]

The flora of the Cenozoic has been dominated by flowering plants (angiosperms), which have become the most diverse and widespread group of plants. In terms of fauna, the Cenozoic has seen the dominance of mammals, with the evolution of many groups, including primates, cetaceans (whales and dolphins), and artiodactyls (hoofed mammals). The era has also witnessed significant avian diversification.

Human Evolution[edit | edit source]

The Cenozoic Era is crucial for understanding human evolution. The earliest hominids appeared in the late Neogene, with the genus Homo emerging in the Quaternary. The development of tool use, language, and culture has allowed humans to become the dominant species on Earth.

Conclusion[edit | edit source]

The Cenozoic Era, with its significant climatic and geological changes, has played a crucial role in shaping the modern world. The evolution of life, especially the rise of mammals and humans, marks this era as a period of profound biological transformation.


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Contributors: Prab R. Tumpati, MD