What extinction is
Definition
Extinction
The permanent loss of all members of a species, so that none remain alive anywhere.
- Extinction is the permanent loss of all members of a species, so none are left alive anywhere.
- A species becomes extinct when it cannot survive or reproduce fast enough to cope with the changes it faces.
- Once a species is extinct it cannot return, so its alleles are lost for good.
Example
The dodo became extinct after humans, and the animals they brought with them, hunted it and destroyed its habitat.
The causes of extinction
- New predators can kill so many of a species that it cannot recover.
- New diseases can spread through and wipe out a species.
- New or more successful competitors can take the food or space the species needs.
- Environmental change, such as a changing climate, can make the habitat unsuitable.
- Habitat destruction, often by humans, removes the place a species needs to live.
- A single catastrophic event, such as a huge volcanic eruption or an asteroid strike, can cause a mass extinction.
Note
Most causes come down to the environment changing faster than the species can adapt.
Key Idea
A species becomes extinct when it cannot adapt fast enough to survive a change it faces.
Self review
- Define extinction.
- Give three causes of extinction.
- Why can a new competitor drive a species extinct?
- What kind of event can cause a mass extinction?
