99.9% of all species that have ever existed are extinct. Usually species live for 2-10 million years

Ordovician
Devonian
Permian
Trissiac
Cretaceous

Mass extinctions can be caused by global warming and cooling, large changes in sea level and ocean water acidity, volcanic eruptions, large asteroids hitting the planet and competition from newly migrated species

current extinction rates are way higher than background rates. Species are becoming extinct 100 times faster than prehuman times

Some species are more vulnerable to extinction because they don't breed frequently , they have a specific diet or habitat, live in small range, are rare, and commercially valuable

island species are more vulnerable because they are specialists

generalists are more likely to adapt to human dominated landscapes and some may even become pests

Seedbanks and botanical gardens are used to preserve genetic information and the seeds of endangered plant species

wildlife farms: Breeding animals for commercial purposes, help reduce hinting in the wild, species can be released to boost wild populations

zoos and aquariums: Preserve some critically endangered animal species to one day reintroduce them to wild habitats