The Cambrian spanned from 539–485 million years ago and is the first period of the Paleozoic Era of the Phanerozoic. The Cambrian marked a boom in evolution in an event known as the Cambrian explosion in which the largest number of creatures evolved in any single period of the history of the Earth.

2025年3月19日 · The Paleolithic Period was an ancient cultural stage of human development marked by chipped stone tools. It has traditionally been considered to have begun 2.58 million years ago, but newer evidence suggests that it may have started 3.3 million years ago.

The Paleolithic or Palaeolithic (c. 3.3 million – c. 11,700 years ago) (/ ˌ p eɪ l i oʊ ˈ l ɪ θ ɪ k, ˌ p æ l i-/ PAY-lee-oh-LITH-ik, PAL-ee-), also called the Old Stone Age (from Ancient Greek παλαιός (palaiós) ' old ' and λίθος (líthos) ' stone '), is a period in …

2025年2月17日 · Paleozoic Era, major interval of geologic time that began 538.8 million years ago with the Cambrian explosion, an extraordinary diversification of marine animals, and ended about 252 million years ago with the end-Permian extinction, the greatest extinction event in …

Paleo-Indians were the first peoples who entered and subsequently inhabited the Americas towards the end of the Late Pleistocene period. The prefix paleo- comes from the Ancient Greek adjective: παλαιός, romanized: palaiós, lit. 'old; ancient'.

2013年6月20日 · The Paleozoic Era, which ran from 541 million to 251.9 million years ago, was a time of great change on Earth. The era began with the breakup of one supercontinent and the formation of another....

Paleozoic Era, or Palaeozoic Era, Major interval of geologic time, c. 542–251 million years ago. From the Greek for “ancient life,” it is the first era of the Phanerozoic Eon and is followed by the Mesozoic Era. It is divided into six periods: (from oldest to youngest) the Cambrian, Ordovician, Silurian, Devonian, Carboniferous, and ...

Paleozoic (541-252 million years ago) means ‘ancient life.’. The oldest animals on Earth appeared just before the start of this era in the Ediacaran Period, but scientists had not yet discovered them when the geologic timescale was made.

2023年7月5日 · During the Paleozoic Era (541 to 251.9 million years ago), fish diversified and marine organisms were very abundant. In North America, the Paleozoic is characterized by multiple advances and retreats of shallow seas and repeated continental collisions that formed the Appalachian Mountains.

2024年8月21日 · The Paleozoic Era was dominated by marine organisms, but by the middle of the era, plants and animals had evolved to live and reproduce on land, including amphibians and reptiles. Fish evolved jaws and fins evolved into jointed limbs.