Geology

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Triassic period – pine trees and pterodactyls

By | 2017-06-25T01:47:43+00:00 June 25th, 2017|Biology, Geology|

A turtle in the desert During the Triassic period (about 248 to 199 million years ago), most of Earth's land continued to stick together in one big supercontinent, Pangaea. Because the middle of Pangaea was so far from the oceans, it was very dry there, like a desert. The whole world was generally [...]

Tertiary period – mammals and mountains

By | 2017-06-25T01:35:37+00:00 June 25th, 2017|Biology, Geology|

Large animals evolved like moose The Tertiary period begins with the catastrophe that killed off the dinosaurs, about 65 million years ago, and it lasts down to 1.8 million years ago. With nearly all of the dinosaurs gone, there was plenty of room on Earth for the mammals to have lots of babies, [...]

Silurian period – Fish get jaws

By | 2017-06-25T01:28:05+00:00 June 25th, 2017|Biology, Geology|

Trout swimming The beginning of the Silurian period was about 443 million years ago. Some environmental problem at the end of the Ordovician period (probably ice ages) killed most of the plants and animals on Earth. The creatures that survived this extinction were the ones that were most able to change quickly to [...]

Quaternary period – modern times

By | 2017-06-24T16:56:54+00:00 June 24th, 2017|Biology, Geology|

The Quaternary period began about 1.8 million years ago (1,800,000 years ago). It is still going on today - we live in the Quaternary period. So far, it's a much shorter period than the others. At the beginning of the Quaternary period, early people in Africa were already using stone tools. The climate was mostly [...]

Proterozoic Eon – eukaryotes to worms

By | 2017-06-24T16:51:41+00:00 June 24th, 2017|Biology, Geology|

Two and a half billion years ago, the Archaean Eon ended and the Proterozoic Eon began. Trillions of prokaryote cells lived in Earth's oceans. Some of these cells could photosynthesize their energy from sunlight, water, and carbon dioxide. These photosynthesizing cells pooped out a lot of oxygen. By about 2.3 billion years ago, the iron [...]

Permian period – Reptiles and pine trees

By | 2017-06-24T16:42:29+00:00 June 24th, 2017|Biology, Geology|

Crocodiles About 290 million years ago, the Carboniferous period ended and the Permian period began. Almost all of the land on Earth grouped together in one big supercontinent we call Pangaea, which reached all the way from the North Pole to the South Pole. With all the land grouped together, the climate got [...]

Ordovician Period – limestone and liverwort

By | 2017-06-24T16:37:22+00:00 June 24th, 2017|Geology|

Octopus At the end of the Cambrian period, about 488 million years ago, most of the plants and animals living on Earth died, because of some catastrophe that we don't know much about. This catastrophe marks the beginning of the Ordovician period. Sea levels were very high during the Ordovician period, and most [...]

Jurassic Period – dinosaurs and ferns

By | 2017-10-14T15:12:59+00:00 June 24th, 2017|Geology, When|

A dinosaur skeleton When the Jurassic period began, about 199 million years ago, a lot of animals had just become extinct in the catastrophe that ended the Triassic period. This left room for the dinosaurs to have a lot of baby dinosaurs. Soon all different kinds of dinosaurs were living all over the [...]

Quick summary of geological eras

By | 2017-06-24T00:52:54+00:00 June 24th, 2017|Geology, History|

Fossil spider from the Cretaceous era Geologists divide the history of the Earth into eons and eras. That's so they don't have to always be saying "400 million years ago" or whatever. The earliest period was the Hadean Eon. The Hadean Era started when the Earth formed about 4.5 billion years ago. It lasted [...]

Hadean Eon – Earth, Moon, proteins, RNA

By | 2017-06-24T00:39:01+00:00 June 24th, 2017|Geology|

Volcano Scientists named the Hadean Eon after the Greek god Hades, who ruled the underworld. That's because during most of the Hadean period the surface of the Earth must have been like our image of Hell. The Hadean Eon began when the planet Earth first began to form, about 4.5 billion years ago. [...]