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Cambrian period 570-500MYA
the Cambrian period had an abundant amount of lifeb in the ocean.Water also dominated earth covering 90% of the earths surface. -
Ordovician period 488-443 MYA
The north area of the tropics were entirely ocean.Diverse marine invertbrate. -
silurian period
During the time continental landmasses were low and sea levels were rising.This meant rich shallow sea ecosystems with new ecological niches.Silurian fossils show evidence of extensive reef building and the first signs that life beginning to colonize the new estuary.fresh water and terrestrial ecosystems. -
Devonian period
It is often known as the "Age of Fishes." although signficant events also happened inthe evolution of plants.the first insects and other animals.By the mid-Devonian, the fossil record shows evidence that there were two new groups of fish that had true bones, teeth,swimm bladders and gills.The lobe-finned fish were more common diuring the deconian than the Ray fins, but largely died out. -
Carboniferous period
the placodems, or amored fish, that had ruled the Devonian seas, became extinct with the emd pf the Devonian period. They were replaced with fish that looked more like our modern fish.Many species of fish and sharks devloped in the warm, humid climate and swampy conditions of this period. -
Permian period
The permian period represented the last gasp for much early prehistoric life. The period, and the paleozonic era, came to a calamitous close 251 million years ago. Marking a biological dividing line that few animals crossed.The permian extinction-the worst extinction event in the planets history-is estimated to have wiped out more than 90 percent. -
trassic period
The mesozoic Era is often known as the age of Repties.Two groups of animals survived the permian Extinction: Therapsids, which were mamml-like reptiles,and the more reptilian Archosaurs. The first mammals evolved near the end of te triassic period frpom the nearly extinct therapsids. -
Quaternary period
At the start of the Quaternary, the continents were just about where they are today, slowing inching here and there as the forces of plate tectonics push and tug them about. But throughout the period, the planet has wobbled on its path around the sun. The slight shifts cause ice ages to come and go. By 800,000 years ago, a cyclical pattern had emerged: Ice ages last about 100,000 years followed by warmer interglacials of 10,000 to 15,000 years each. The last ice age ended about 10,000 years ago. -
Jurassic period
Ferms amd gingkoes, complete with roots and vascular tissue to mov water and nutrients and a spore system of reproduction, were the dominant p lants of teh early Jurassic.Retiles were the dominant animal life forms during the jurassic period.Early mammals were mostly very small herbivores or insectivores and were not in competition with the larger. -
teritory period
Tertiary is the former term for the geologic period from 66 million to 2.58 million years ago, a time span that lies between the superseded Secondary period and the Quaternary. The Tertiary is no longer recognized as a formal unit by the International Commission on Stratigraphy,[1][2][3][4] but the word is still widely used. The traditional span of the Tertiary has been divided between the Paleogene and Neogene Periods and extends to the first stage of the Pleistocene Epoch, the Gelasian age. -
Cretaceous period
One of the hailmarks of tghe Cretaceous period was the development and radiation of the flowering plants,During the Cretaceous period, birds replaced the pterosaurs in the air.About 65 million years ago.Nearfly all large ventasbrates and many tropical invertabrates extinct in what was clearly a
