click below
click below
Normal Size Small Size show me how
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. |