click below
click below
Normal Size Small Size show me how
8th Science Review
An 8th Grade Science Review
| Term | Definition |
|---|---|
| Law of Superposition | as layers get deeper, they also get older |
| Catastrophism | the idea that quick and violent events change Earth |
| Uniformitarianism | the idea that things happening on Earth now also happened in the past |
| Radiometric Dating | figuring out the age of an object using its isotopes |
| Index Fossil | a fossil that can help figure out the age of its surroundings |
| Natural Selection | the idea that good traits will survive and change animals over time |
| Variation | a difference in a trait |
| Mutation | a random genetic change |
| Adaptation | a trait that helps an organism survive or reproduce |
| Vestigial Structure | a structure that is no longer needed, but is still there |
| Pathogen | a disease making organism: there are 4 types (Bacteria, Virus, Fungi, Protists) |
| Vector | anything that carries or gives a disease to another organism |
| Disease | a condition that is not normal, and affects an organism |
| Epidemic | when a disease spreads quickly and widely in small area |
| Pandemic | when a disease spreads quickly and widely in a large area/world wide |
| Nuclear Power | it makes a lot of power and is safe when you mine, but it creates toxic waste |
| Hydroelectric Power | renewable and creates no pollution, but it destroys the homes of some animals |
| Solar Power | renewable and is getting better, but it is expensive and the sun isn't always shining |
| Wind Power | renewable and can be used at night, but it only works when there is wind |
| Natural Gas | cleanest fossil fuel and and doesn't leave anything dangerous behind, but it is nonrenewable |
| Coal Power | we are already using it across the world and always provides power, but it is nonrenewable and harmful |
| Renewable | a resource that you won't run out of |
| Nonrenewable | a resource that you can run out of |
| Fossil Fuels | the remains of plants and animals that died millions of years ago |