1. Protect the natural habitat so the animal/plant/insect, etc has somewhere to live.
2. Safe guard individuals of the species so if it dies out in the wild there will be living specimens to reproduce.
3. Educate people so they don't encroach on natural habitat more than necessary.
4. Pass legislation to protect both the habitat and endangered species.
5. Provide alternatives to the human population for land management, food, development, water resources, etc. so endangered species are not overwhelmed and made extinct.