| A | B |
|---|
| biodiversity | the number and variety of species on earth |
| poaching | illegal hunting |
| keystone species | any species that is essential to the health of an ecosystem |
| threatened species | any species with a declining pop that could be endangered |
| gene | segment of DNA |
| mass extinction | death of species in a relatively short period of time |
| exotic species | organism that is not native to a region |
| genetic diversity | diversity of all the different genes found in a population |
| introduced exotic species | major threat to islands |
| biomagnification | pollutants accumulate at successive level of the food chain |
| germ plasm | the genetic material of a species |
| hotspots | the most threatened areas of high species diversity on earth |
| ecosystem diversity | variety of habitats and communities |
| tropical rainforests | part of the world with greatest number of extinctions |
| 25 percent | percent of species expected to go extinct betw. 1900 and 2100 |
| endangered species | a species in danger of extinction |
| habitat destruction | accounts for 75% of the extinctions |
| endemic species | species native to and found onlu within a limited area |
| groups of organisms in most danger of extinction | samll, migrating or those needing special habitats |
| DDT | this almost wiped out the bald eagle population |
