Cenozoic

The Cenozoic Era is the time period we live in now. It started about 66 million years ago after a big event that caused many species, including the non-avian dinosaurs, to disappear. This event is thought to have been caused by a huge space rock hitting Earth, called the Chicxulub impactor.

This era is also called the Age of Mammals because mammals became the most common land animals. Different kinds of mammals lived in different places — some in the north and others, called marsupials, mainly in Australia and parts of South America. Birds also became very successful and diversified during this time.

The Cenozoic saw big changes in Earth's climate. Early on, it was much warmer, but later it became cooler and drier, especially during the time known as the Quaternary glaciation. During this era, the continents moved to the positions we see today.

Nomenclature

The word Cenozoic comes from Ancient Greek words meaning "new" and "life." It was first used in 1840 by a British scientist named John Phillips. This era is sometimes also called the Cænozoic, Caenozoic, or Cainozoic.

The Cenozoic is called "new life" because it came after the Mesozoic era, which means "middle life," and the Paleozoic era, meaning "old life."

Divisions

The Cenozoic Era is split into three periods: the Paleogene, Neogene, and Quaternary. It also has seven epochs: Paleocene, Eocene, Oligocene, Miocene, Pliocene, Pleistocene, and Holocene. These divisions help scientists organize important events from this time.

The Paleogene period started 66 million years ago after the dinosaurs went extinct. During this time, modern mammals began to appear, and the world's continents started moving into their current positions. The Neogene period followed, where grasses spread widely and many new animals evolved. Finally, the Quaternary period began about 2.58 million years ago and includes times when large glaciers covered parts of the world. This period also saw the evolution of humans and many changes to the planet's climate and landscapes.

Tectonics

Geologically, the Cenozoic is the era when the continents moved into their current positions. Australia-New Guinea, having split from Pangea during the early Cretaceous, drifted north and, eventually, collided with Southeast Asia; Antarctica moved into its current position over the South Pole; the Atlantic Ocean widened and, later in the era (2.8 million years ago), South America became attached to North America with the isthmus of Panama.

India collided with Asia 55 to 45 million years ago creating the Himalayas; Arabia collided with Eurasia, closing the Tethys Ocean and creating the Zagros Mountains, around ( https://geoltime.github.io/?Ma=35) million years ago.

The break-up of Gondwana in Late Cretaceous and Cenozoic times led to a shift in the river courses of various large African rivers including the Congo, Niger, Nile, Orange, Limpopo and Zambezi.

Climate

The climate during the early part of the Cenozoic Era was very warm and wet, with forests growing near the poles and no permanent ice. Seas were much higher than today. Over time, the climate began to cool, especially after India crashed into Eurasia, forming the Himalayas. This cooling led to ice building up on Antarctica. Later, when South America connected to North America forming the Isthmus of Panama, ocean currents changed, leading to even cooler climates and the beginning of ice ages.

Life

After a big event that changed Earth long ago, small animals like mammals and birds became the main forms of life. Mammals grew and changed a lot, filling many places on land, in the water, and even in the air. Some birds, called "terror birds," became very big and could not fly.

This time period is also known as the Age of Mammals because so many different kinds of mammals appeared. Plants with flowers and many types of insects also thrived. Grasses became very important, affecting the animals that ate them. Snakes also became more varied during this time. The Cenozoic had many interesting animals, including whales, early primates, sabre-toothed cats, mastodons, mammoths, and giant rhinoceroses. Changes in climate and Earth’s shape helped shape the evolution of these mammals.