A species that is in danger of becoming endangered; it is likely pressured in some of its habitats or is having other issues.
A species that is in danger of becoming extinct, either through natural processes or though issues caused by humans.
Background extinction rate
The rate at which species would naturally go extinct with no outside influences. This extinction is completely from natural causes.
When an animals habitat is no longer a cohesive whole by is instead divided into multiple smaller pieces.
The process in which natural habitat is rendered functionally unable to support the species present.
When the resources of an area are used well past the point of sustainability on towards the destruction of the area.
Marine Mammal Protection Act (MMPA) 
Protects marine mammals from falling below their optimum sustainable population levels.
Endangered Species Act Program for the Protection of Threatened Plants and Animals and Their Habitats (ESAP) 
Prohibits commerce of those species considered to be endangered or threatened.