Extinction

What do dinosaurs, Tasmanian Tigers and Hoopoe Starlings have in common? The answer is the subject of today's lab, extinction. Extinction occurs when a species cannot survive in its environment to reproduce and cannot move to a new one. Woolly mammoths, for example, were thought to have died as a result of climate change making its habitat and the rest of the planet too warm. Extinction has happened for as long as there has been life on earth. In fact, an estimated 99% of all species that ever existed have gone extinct.

Most of these extinctions happened over time because of environmental changes like our woolly mammoth. But other factors such as competition for resources with other species and inability to avoid predation can also drive a species to extinction. Take these fish, for example. Both species share a habitat, but the green fish is better at evading predators making its survival more likely and eventually driving the orange fish extinct. Over hunting and other human made phenomena such as pollution can also cause the extinction of a species.

Extinctions that occur on a global level are called mass extinctions and these are typically caused by major catastrophic events li