They fill a space (niche) in a food web.
Humans are the main reason that puma is endangered species. As a species, the puma is not an endangered species. Only the Florida race is endangered.
The usual reason for any species on the list is there are not enough adult members.
Which of these is not a reason that species become extinct
You Shouldn't! There is no reason to destroy endangered tree species. You shouldn't destroy endangered tree species.
Habitat loss threatens the jaguar, but this species is not an endangered species, rather listed as near threatened.
For the same reason that dogs are one species but many different colors.
The gray wolf is not an endangered species. Listed as least concern by the IUCN.
Humans.. mostly
For the same reason every species does. They have to survive and without new animals in their species they would die out soon.
Humanity itself causes endangerment of animal species due to poaching, deforestation and pollution.
there is more solar energy available in the tropics than in the temperate zones.
For the same reason humans and other animals have babies - to perpetuate the species !