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The Era's - Coggle Diagram
The Era's
Paleozoic Era
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It was when many organisms evolved including some that had hard parts like shells and outer skeletons. So many different new lives formed in this short period of time. All the animals of this time lived in the sea, many of them had no backbones and invertebrates. Some of them were jellyfish, worms,sponges, etc.
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The second segment of the Paleozoic Era was called the Ordovician Period in this period of time where the first vertebrates appeared, also the first insects may have evolved in this time. A lot of plants grew, every main group of fish including the sharks were present in the ocean.
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The first land vertebrates were lungfish that had strong muscular fins, the first amphibian there ever was evolved from this very own fish.
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The third segment of the Paleozoic Era was the Carboniferous Period, in this period the amniote egg evolved. This adaptation of laying eggs helped other animals lay them on land without them drying out. This coincides with the appearance of reptiles in the fossil record. Huge insects evolved into huge dragonflies and cockroaches, plants that resemble plants that live in tropical areas now are giant Ferns, mosses, and cone bearing plants.
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Earth’s continents started to form a supercontinent known as Pangea, this caused deserts to expand in the tropics and sheets of ice to cover land closer to the south pole.
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A major change occurred in the Permian Period, almost all the animals died. A lot of living things became extinct. Scientists estimate that about 90% of the ocean’s animals died and 70% of the land animals died. Scientists aren’t sure what caused this extinction but they have many theories.
Cenozoic Era
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This era begins with the Paleogene and Neogene periods. Earth’s climate was cool and the super continent drifted apart, the oceans widened and mammals like whales and dolphins evolved. Forests thinned so plants and grasses became dominant.
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At the start of the quaternary period large sheets of ice began to appear on Earth’s surface. The climate continued to cool and warm in cycles. In an Ice Age 30% of the surface was covered in thick glaciers.
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The quaternary period is also known as the Age of Humans, modern humans appeared about 190,000 years ago. By about 12,000 to 15,000 years ago humans migrated to every continent except Antarctica.
Mesozoic Era
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Some living things survived the mass extinction some of these were fish, insects, reptiles, conifers. The reptiles were really successful in this time that it was also called the Age of Reptiles. Some dinosaurs appeared during the first period of this era called the Triassic Period
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Mammals appeared in the Triassic period too, in this period they were the size of a mouse.
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Dinosaurs were dominant land animals in the Jurassic Period of this era. Scientists found out that there were dinosaurs that ate plants and some that were predators. The oceans were filled with different types of organisms. The first known birds appeared in the skies, there were also flying reptiles.
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In the Cretaceous period there were still dinosaurs and reptiles. Birds started to replace flying reptiles. One of the most important events that happened in this period were the flowering plants, these produce seeds that are inside a fruit, some of them are magnolias, figs and willows.
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Another mass extinction happened and scientists think that this occurred when an asteroid hit the earth at a time when there was extreme volcanic activity in the area that is now India. This wiped out more than half of all plants and animal groups including dinosaurs.