Senozoik

Senozoik, or the Cenozoic Era, is the most recent major era of the geologic timescale. It began about 66 million years ago, after the mass extinction at the end of the Cretaceous, and continues to the present. The name comes from Greek words for "new life," reflecting the rapid diversification of mammals, birds, and flowering plants that characterize the era. It succeeded the Mesozoic Era.

The era is divided into three main periods: Paleogene (approximately 66–23 million years ago), Neogene (23–2.6 million years ago), and Quaternary (2.6 million years ago to present). The Paleogene includes the epochs Paleocene, Eocene, and Oligocene; the Neogene includes Miocene and Pliocene; the Quaternary includes Pleistocene and Holocene.

During the Paleogene, mammals and birds diversified, and flowering plants spread widely. Global climates shifted from warm to cooler conditions through the Oligocene and into the Miocene, fostering grasslands and the evolution of grazing mammals. The Neogene saw further diversification and the spread of many modern plant and animal lineages, with continued cooling and the development of more variable climates.

Geological and climatic changes in the Senozoik include major tectonic activity, such as the uplift of the Himalayas and the Alps, changes in ocean currents, and long-term cooling trends that contributed to glacial cycles in the late Cenozoic. The late era also coincided with significant ecological shifts that shaped modern ecosystems.

Humans are part of the late Cenozoik, with hominins appearing in Africa several million years ago and Homo sapiens emerging about 300,000 years ago; the most recent part of the era is the Holocene, which encompasses the rise of human civilization.