the diversity of plant and animal life in a particular habitat (or in the world as a whole)
extinct species
a species that was once present on Earth but has died out
endangered species
a species whose numbers are so small that the species is at risk of extinction
threatened species
a species that could become endangered in the near future
introduced species
species moved by humans to new geographic areas, either intentionally or accidentally
native species
Species that are originally found in a certain area.
acid rain
rain containing acids that form in the atmosphere when industrial gas emissions (especially sulfur dioxide and nitrogen oxides) combine with water
ozone depletion
Decrease in concentration of ozone (O3) in the stratosphere. See ozone layer.
conservation biology
the study and implementation of methods to protect biodiversity
habitat restoration
the process of taking action to bring a damaged habitat back to a health condition
captive population
population of organisms cared for by humans
reintroduction program
programs that release organisms into an area where their species once lived in hopes of reestablishing naturally reproducing populations