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chapter 6 studystack
changes over time
| Term | Definition |
|---|---|
| Natural Selection | The process by which individuals are better adapted to their environment and are more likely to survive and reproduce. |
| Variation | Any difference between individuals of the same species. |
| Half life | The time it takes for half of the atoms in a sample to decay. |
| Scientific theory | A well tested concept that explains a wide range of observations. |
| Punctuated equilibria | The theory that species evolve quickly during short bursts of time. |
| Fossil record | Documentation of the millions of fossils scientists have collected over time. |
| Radioactive elements | Unstable elements that decay or break down into different elements. |
| Homologous structures | Similar structures that related species have inheritedfro common ancestors. |
| Mold | A holow place left where the fossil has decayed or dissolved. |
| Relative dating | A process comparing the age of two fossils by their placement in the layers of sedimentary rock layers. |
| Evolution | Gradual changes in a species over time. |
| Petrified fossils | Fossils that are buried in sediments and actually changed to rock. |
| Adaption | A trait that helps an organism survive and reproduce. |
| Gradualism | The theory that evolution occurs slowly but steadily. |
| Branching tree | A diagram that shows how scientists think different groups of organisms are related. |
| Radio active dating | A process that tests the radioactive materials within a fossil to tell its actual age ( aka absolute dating). |
| Fossils | Preserved remains of an organism that lived in the past. |
| Extinction | When no member of the species is still alive. |
| Cast | A copy of the shape of the organism that made. |
| Competition | This is a factor in Natural Selection as organisms attempt to survive using the same limited resources( food,shelter...) |
| Homolougus structures | Evidence that related species had a common ancestor because of the way their bodies are anatomically constructed in similar ways. |
| Overproduction of offspring | This factor in Natural Selection happens when there are more offspring than can possibly survive on the given recources. |
| Species | A group of organisms that can mate together and produce fertile offspring. |
Created by:
22mryan
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