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540 BCE
Cambrian Period (Paleozoic Era)
This time period lasted about 53 million years. In early cambrian, Earth was cold for the most part and gradually started becoming warmer. Overtime, first ever life on earth had come about because of the 'Cambrian Explosion'. This explosion caused major groups of animals to form; therefore, in today's period, we still find some fossils from then. One species that dominated called Trilobites. No mass extinction yet. -
483 BCE
Ordovician Period
This time period lasted about 45 million years. North of the tropics was almost entirely ocean and there were diverse marine invertebrates. Some of the marine life are Graptolites, Trilobites, Brachiopods, and Conodonts. Near the end of the period, a mass extinction had occurred caused by gamma-ray burst, killing about 60% of marine life then. -
450 BCE
Silurian Period
Occurred from 443 million to 416 million years ago. The supercontinent Gondwana - which was form in the Ordovician Period - had drifted southward and covered most of the southern latitudes. With marine life, they still lived under the sea, but eventually life had moved onto land. plants. Lichens were the first photosynthetic organisms to cling to lands of the early continents. -
400 BCE
Devonian Period
This period lasted about 417 million years to 354 million years ago. North America and Europe had collided which formed a large continent called Euramerica. Another large land mass was Gondwana which was made up of South AMerican, Africa, Antarctica, India and Australia. Plants covered the land; formed vascular tissues to carry water and food through roots. With plant life, insects and other animals had a good home. there were ancient sharks and other ancient fish. -
350 BCE
Carboniferous Period
Lasted from 363 million to 290 million years ago. Because of the large masses of ice sheets which locked up water, sea levels dropped which led to the increase of terrestrial habitat. MISSISSIPPIAN - a period of marine transgression in the northern hemisphere. Sea levels was so high. PENNSYLVANIAN - lasted 323 million to 298 million years ago. This is where the coal-productive beds of this age are widespread. -
300 BCE
Permian Period (Paleozoic Era - End)
Started 299 million years ago. The supercontinents had emerged which then created Pangaea. Northern areas suffered increasingly from the intense heat and great seasonal fluctuations between wet and dry conditions. swamps were replaced by conifers, seed ferns, and other plants. reptiles that were cold-blooded had to deal with temperatures varying from below freezing and 100 degrees. -
250 BCE
Triassic Period (Mesozoic Era)
Occurred between 251 million to 199 million years ago. At the beginning of this period, the continents were concentrated in a C-shaped known as Pangaea. Climate was generally dry, hot summers and cold winters. With the permian extinction, 95% were wiped out by high carbon dioxide levels. Early triassic, groups of reptiles returned to the ocean. -
200 BCE
Jurassic Period
Occurred about 199 million to 145 million years ago. The supercontinent pangaea began drifting apart. With higher latitudes, warm, humid climate allowed lush jungles to cover most lands. Large reptiles and the largest known dinosaurs were dominating both land and sea in this period. -
100 BCE
Cretaceous Period (Mesozoic Era End)
Lasted about 79 million years ago. continent positions were different from today's own. sections of the supercontinent Pangaea were drifting apart. By the middle of the period, ocean levels were much higher where most landmass were underwater. They have come to the conclusion that there were species of dinosaurs that has evolved into taking flight. This period is where dinosaurs have went extinct. -
50 BCE
Tertiary Period (Cenozoic Era)
Lasted from 66 million to 2.6 million years ago. Climates there were very warm and moist. Most of Earth was tropical or sub-tropical. Near the middle of the period, the climate began to cool; therefore, ice age had begun. Animals that lived in this period were mammals; examples include bears, hyenas, dogs, cats, seals, monkeys, lemurs, apes, and then humans. -
Quaternary Period (Cenozoic Era End)
Divided into two epochs: Pleistocene (2.5 million to 11.7 thousand years ago) & Holocene (11.7 thousand years ago to today). Pleistocene - Glaciers covered huge parts of Earth. Most recent Ice Age that occurred. People around this period had caused a small amount of extinction due to hunting certain groups of animals.
Holocene - current period of time. everything around us is the Holocene period. The changes from 11 thousand years ago was created by us humans.
