All species

Billions of years of evolution have given rise to the Earth’s rich biodiversity, from the smallest unicellular microorganisms to the largest living animal, the blue whale. The best estimates of the total number of living species on Earth typically fall between a staggering 5 and 30 million. Of these, scientists have thus far described around 1.8 million different species of mammal, bird, amphibian, reptile, fish, invertebrate, fungi, and plants and algae, as well as numerous other organisms. However, with human activity now pushing the rate of species extinction in excess of 1,000 times the ‘natural’ rate, conservation efforts have never been more vital.

Explore ARKive for videos and images of endangered species, and learn about their biology, threats, conservation and more in our species fact-files.