Extinction
Species disappear when they cannot adapt.
About this topic
Extinction occurs when the last individual of a species dies. It is a natural process: over 99% of species that ever lived are extinct. Causes include habitat loss, climate change, disease, competition and overhunting. Mass extinctions have happened five times, such as the end-Permian and the end-Cretaceous that removed non-avian dinosaurs.
Today's extinction rate is far above background, and many scientists speak of a sixth mass extinction driven by humans. Conservation aims to prevent further losses.
Five mass extinctions have occurred in Earth's history, the most famous ending the dinosaurs about 66 million years ago after an asteroid struck the Yucatan. Scientists now warn of a sixth, driven by humans, with extinction rates far above the natural background. The dodo, passenger pigeon and thylacine are examples of recent losses.
Island species and those with small ranges are especially vulnerable, and invasive species such as rats and cats can wipe out native birds. Conservation uses protected areas, captive breeding and seed banks to prevent loss. Students sometimes think extinction is always caused by humans; many occurred naturally. However, losing species also weakens ecosystems, since each plays a role in food webs, pollination or soil health.
Key ideas
- Mass extinctions
- Habitat loss and invasive species
- Fossils record extinct life
Quick check
Use cases: where Extinction helps
- Homework: review the key idea behind Extinction before you start a problem set.
- Exam revision: use the quick check to test whether you can recall Extinction without notes.
- Visual learning: play with the interactive lab to see how Extinction changes when you adjust its inputs.
- Teaching a friend: explain Extinction in your own words, then compare your version with the key ideas.
Biology underpins medicine, farming, conservation and biotechnology.
Frequently asked questions
What is Extinction?
Species disappear when they cannot adapt.
What will I learn in Extinction?
Mass extinctions. Habitat loss and invasive species. Fossils record extinct life.
Is Extinction part of Biology?
Yes. It is one of 150 Biology topics on LearnViz HighSchoolEdu, with 3 key ideas, a live animation and a quick check.
Does the Extinction lab work on a phone or tablet?
Yes. The animation resizes to fit your screen and supports touch, so you can drag, tap and slide with your finger.
How should I study Extinction?
Read the summary and key ideas first, play with the interactive lab to see the idea in motion, then answer the quick check. If you get a question wrong, go back to the key idea it tests.
Do I need an account, and is my progress saved?
No account is needed. Marking a topic as learned is saved in your own browser, so it stays on that device and is not sent to a server.