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Ch 8
The History of Life on Earth
Term | Definition |
---|---|
fossil | the solidified remains or imprints of once living organisms |
relative dating | a method of estimating how old a rock or fossil is compared to other rocks or fossils |
absolute dating | a method of learning the age of fossils in years |
geologic time scale | a calendar used by geologist to divide the Earth's history |
extinct | when species die out completely |
plate tectonics | the theory of how plates moved |
precambrian time | the longest part of earth's history which lasted from the time Earth formed (4.6 billion years ago) until about 542 million years ago |
Paleozoic era | the second longest part of the Earth's history beginning about 542 million years ago and ending about 251 million years ago |
Mesozoic era | the middle life period that lasted from about 251 million years ago to 65.5 million years ago |
Cenozoic era | the recent life era which began about 65.5 million years ago |
primate | a group of mammals that consist of humans, monkeys, and apes |
hominid | humans and their human like ancestors |
australopithecine | early apelike hominids |
neanderthal | recent hominids that hunted large animals, made fires, and wore clothing, |