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Biology Vocab
Chapter 12
Term | Definition |
---|---|
Relative Dating | Estimate of the age of a fossil based on the location of fossils in strata. |
Radiometric Dating | Technique that measures the natural decay rate of isotopes to calculate the age of material. |
Isotope | Form of an element that has the same number of protons but a different number of neutrons as another element. |
Half Life | Amount of time it takes for half of the isotope in a sample to decay into its product isotope. |
Index Fossil | Fossil of an organism that existed during only specific spans of geologic time across large geographic areas. |
Geologic Time Scale | Time scale representing the history of Earth. |
Era | Second largest unit of geologic time, lasting tens to hundreds of millions of years and consisting of two or more periods. |
Period | Unit of geologic time that lasts tens of millions of years and is associated with a particular type of rock system. |
Epoch | Smallest unit of geologic time, lasting several million years. |
Nebula | Rotating cloud of gas and dust. |
Ribozyme | RNA molecule that ca catalyze specific chemical reactions. |
Cyanobacteria | Bacteria that can carry out photosynthesis. |
Endosymbiosis | Ecological relationship in which one organism lives within the body of another. |
Paleozoic | Era of geologic time (from 544 to 248 million years ago) during which members of every major animal group alive today evolved. |
Cambrian Explosion | Earliest part of the Paleozoic era, when a huge diversity of animal species evolved. |
Mesozoic | Era during which dinosaurs roamed Earth (from 248 million years ago to 65 million years ago). |
Cenozoic | Geologic time period that began 65 million years ago and continues today. |
Primate | Mammal with flexible hands and feet, forward-looking eyes, and enlarged brains relative to body size. |
Prosimian | Oldest primate group that includes mostly small, nocturnal primates such as lemurs. |
Anthropoid | Humanlike primate. |
Hominid | Primate that walks upright, has long lower limbs, thumbs that oppose the other four fingers, and a relatively large brain. |
Bipedal | Animal that walks on two legs. |