Term | Meaning |
species | A group of organisms whose members sucessfully reproduce among themselves. |
evolution | The changes that occur over time in hereditary features. |
natural selection | Darwin's theory says that organisims best adapted to their enviromen are more likely to survive and pass their traits to offspring. |
variation | The occurance of an inherited trait that makes an individual different from other members of the same species. |
gradualism | A model of evolution, showing a steady , slow, and continious change of one species into new species. |
punctuated equilibrium | A model of evolution, showing the rapid change of a species caused by the mutation of just a few genes. |
fossils | The remains of life from an earlier time. |
sedimentary rock | A type of rock formed when fine particles like mud and sand settle out of water and become cemented together. |
relative dating | Estimating the age of a fossil by comparing it to younger fossils in the rock layers above and to older fossils in rock layers below. |
radioactive element | An element that gives off radiation, a form of atomic energy. |
homologous | Body parts in different species that are similar in origin and structure. |
vestigial structure | A body part that is reduced in size and has no obvious use. |
embryology | The study of the development of embryos, which are the earliest stages of an organism's development. |
primate | The group of mammals to which monkeys, apes, and humans belong and which share several characteristics, such as opposable thumbs. |
homind | The earliest humanlike primates; ate both meat and veggies and walked upright on two feet. |
Homo sapiens | Our own species, a homind primate mammal; evolved 300,000 years ago. |
extinction | The dying out of an entire species. |
endangered species | A species with so few individuals left that it is in danger of extinction. |