Search results
Results From The WOW.Com Content Network
The Cambrian (/ ˈ k æ m b r i. ə n, ˈ k eɪ m-/ KAM-bree-ən, KAYM-) is the first geological period of the Paleozoic Era, and the Phanerozoic Eon. [5] The Cambrian lasted 51.95 million years from the end of the preceding Ediacaran period 538.8 Ma (million years ago) to the beginning of the Ordovician Period 486.85 Ma.
Ferns first appear in the fossil record about 360 million years ago in the late Devonian period. [73] Synapsids such as Dimetrodon were the largest terrestrial vertebrates in the Permian period, 299 to 251 million years ago.
Homininid Era – Period prior to the existence of Hominini; Prehistory – Period between the appearance of Homo ("humans"; first stone tools c. three million years ago) and the invention of writing systems (for the Ancient Near East: c. five thousand years ago). Paleolithic – the earliest period of the Stone Age
500 million years of climate change [7] The Phanerozoic eon, encompassing the last 542 million years and almost the entire time since the origination of complex multi-cellular life, has more generally been a period of fluctuating temperature between ice ages, such as the current age, and "climate optima", similar to what occurred in the ...
Estimates on when the planet’s inner core may have solidified — when iron first crystallized at the center of the planet — once ranged from 500 million to 2.5 billion years ago.
The last common ancestor of all extant eukaryotes is thought to have lived around 1.8 billion years ago. Around 800 million years ago, there was a notable increase in the complexity and number of eukaryotes species in the fossil record. [133] Before the spike in diversity, eukaryotes are thought to have lived in highly sulfuric environments.
Until recently, scientists thought arthropods flourished during the Cambrian Period (538 million to 485 million years ago), which came before the period in which the specimen found by Parry's team ...
The Archean represents the time period from (million years ago). The ... about 4,540 million years ago until 2,500 million years ago. ... levels only 500 million ...