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11 Cards in this Set
- Front
- Back
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geologic time scale
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A way of dividing Earth's entire history into distinct intervals of time. These intervals include eons, eras, periods, and epochs.
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trace fossils
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A fossilized structure, such as a footprint or a coprolite, that formed in sedimentary rock by animal activity on or within soft sediment. Tracks preserved in sedimentary rock are a type of trace fossil.
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mesosaurus
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A fish-eating reptile living 270 million years ago whose fossils are found in both Africa & South America, suggesting these continents were once joined.
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continental drift
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The movement of the continents throughout Earth's history.
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Paleozoic Era
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542 million years ago and ended 251 million years ago. Massive increase in marine life. Fishes , plants, fungi and animals colonized land. Forest of giant ferns covered much of Earth. All major plant groups appeared, except flowering plants. Reptiles, amphibians, worms appeared. Ended when Pangaea formed causing the largest mass extinction ever known - the Permian extinction.
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Mesozoic Era
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Began 251 million years ago, ended 65 million years ago. AGE OF REPTILES. Dinosaurs dominated for about 150 million years. Birds, first mammals, conifers formed large forests, flowering plants. Ended with the Cretaceous-Tertiary extinction, when all the dinosaurs and half of the other animals and plants became extinct.
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Cenozoic Era
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65 million year ago to today. AGE OF MAMMALS.
Mammals (including humans), birds, insects, and flowering plants appeared. Climate changes. Ice Ages |
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Precambrian Time
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From the formation of Earth 4.6 billion years ago to about 542 million years ago. Life on Earth began during this time. First organisms (prokaryotes) appeared in oceans more than 3.6 billion years ago. 1 billion years later, complex organisms (eukaryotes) appeared.
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Permian Extinction
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Largest known mass extinction about 251 million years ago at the end of the Permian Period of the Paleozoic Era. Pangaea formed; shallow inland seas disappeared. About 90% of marine species and 78% of land species became extinct. Reptiles and amphibians survived.
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Cretaceous Tertiary Extinction
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About 65 million years ago, all of the dinosaurs and about half of the animal and plant species became extinct. Possibly caused by an asteroid.
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Cambrian Explosion
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First period in the Paleozoic Era. Many marine life-forms appeared.
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