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THe cambrian period had an abundant amount of marine organisms and the earth was covered in oceans. All life was in oceans.
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Coral fossils were becoming to form at this time. Reef ecosystems still were dominated by algae and sponges.
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In the oceans there was a widespread radiation of crinoids. There was a wide spread of jawless fish and many other forms of fish. Mnay vaskcular plants had evolved during this time period.
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containing fossils of both zosterophylls and trimerophytes, some of the earliest vascular plants. The vegetation of the early Devonian consisted primarily of small plants, the tallest being only a meter tall. By the end of the Devonian, ferns, horsetails and seed plants had also appeared, producing the first trees and the first forests.
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The beginning of the Carboniferous generally had a more uniform, tropical, and humid climate than exists today. Seasons if any were indistinct. Shallow, warm, marine waters often flooded the continents
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massive areas of land and water. the motion of the Earth's crustal plates had brought much of the total land together, fused in a supercontinent known as Pangea.
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Climate was generally very dry over much of Pangaea with very hot summers and cold winters in the continental interior. The Triassic Period was the first period of the Mesozoic Era
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Great plant-eating dinosaurs roaming the earth, feeding on lush ferns and palm-like cycads and bennettitaleans … smaller but vicious carnivores stalking the great herbivores … oceans full of fish, squid, and coiled ammonites, plus great ichthyosaurs and long-necked plesiosaurs … vertebrates taking to the air, like the pterosaurs and the first birds.
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many modern groups of insects were beginning to diversify, and we find the oldest known ants and butterflies. Aphids, grasshoppers, and gall wasps appear in the Cretaceous, as well as termites and ants in the later part of this period. Another important insect to evolve was the eusocial bee, which was integral to the ecology and evolution of flowering plants.
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The beginning of this period was very warm and moist compared to today’s climate. Much of the earth was tropical or sub-tropical. Palm trees grew as far north as Greenland! By the middle of the tertiary, during the Oligocene Epoch, the climate began to cool. Mammals were introduced.
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The age of ice ages. The slight shifts of the earth cause ice ages to come and go. The first modern humans evolved in Africa .
