Extinct is a classification category on the International Union for the Conservation of Nature’s (IUCN) Threatened Species List.
Extinction occurs when a species — also called “taxon” for the list — no longer exists anywhere on earth. When scientists have done extensive research and agree that there is no longer a single individual specimen of the species they declare it extinct. Essentially, extinction represents the termination of a taxon.
In the history of our planet, scientists estimate that 4 billion species have populated it over time, but 99% of those are now extinct animals. Since 1500 alone, approximately 900 species have gone extinct. Among these extinct animals are the West African black rhinoceros, the baiji white dolphin, the Tasmanian tiger, the dodo, and Stellers sea cow.
There are six main reasons why species now become extinct:
- Habitat loss
- Introduction of a foreign species
- Hunting
- Pollution
- Disease
- Loss of genetic variation
Human actions have played a huge role in species extinction in more recent history, but they’re not the only culprit. Of the 99 percent of species that have gone extinct on the planet, most of these extinct animals were victims of cataclysmic events or evolutionary problems. Typically, species have a lifespan of about 10 million years, but there are some that stick around for hundreds of millions. Take jellyfish; they have shimmied around the world’s oceans for about 550 million years! However, just because most animals eventually go extinct doesn’t mean we should not be concerned with their conservation status. When species are unnaturally dying out, to maintain the planet’s ecological balance, we must make an effort to ensure their survival.
