It uses a set of criteria to evaluate the extinction risk of thousands of species and subspecies. These criteria are relevant to all species and all regions of the world, With its strong scientific base, the IUCN Red List is recognized as the most authoritative guide to the status of biological diversity. 

1. Least Concern Species (LC):  There are 14033 animal species and 1500 plant species in this category. Humans also qualify for this classification.
2. Near-threatened Species (NT): There are 3829 identifed species (2657 animals, 1172 plants) in this category.
3. Vulnerable Species (VU): There are currently 5196 animals and 6789 plants classified as vulnerable.
4. Endangered Species (EN): In 2012, IUCN Red List featured 3079 animal and 2655 plant species as endangered.
5. Critically Endangered Species (CR): As of 2014, there are 2,464 animal and 2,104 plant species with this assessment.
6. Species that are Extinct in the Wild (EW): These species are kept in captivity in order to ensure their survival, they do not live in their natural habitats. There are 78 (39 animal, 39 plant) extinct in the wild species in this category.
7. Extinct Species (EX): More than 99 percent of all species, amounting to over five billion species, that ever lived on Earth are estimated to have died out.

Nearly one-third of the amphibians, about half the turtles, one out of every eight birds and one out of every four mammals are faced with extinction. 

• There are so many national organizations that tries to protect endangered species. If you support these organizations you will be helping to protect endangered species.

• Governments can enforce harsher punishments for overhunting and illegal hunting. 

• Children and adults can be educated about the endangered species in their areas and country as a whole.

• We can stop using plastic materials and other toxic substances that are harmful to environment. 

• For example, some parasitic creatures become extinct when their host dies.

• While this may seem like a less important factor, it is actually the most dangerous factor for the nature. 

• Every living being in the world is connected to each other in one way or another. This link is kept by the Food Chain.  When a species becomes extinct, it disrupts the food chain and causes another creature to go extinct. 

• Even the tiniest living being can cause all the life on Earth to die if not protected adequately.