Summary:
- Amphibians evolved about 365 million years ago from a lobe-finned lungfish ancestor.
- For more than 100 million years, amphibians remained the dominant land vertebrates.
- Once reptiles appeared, with their amniotic eggs, they replaced amphibians.
- Amphibians can be found in freshwater and moist terrestrial habitats throughout the world.
- The only continent without amphibians is Antarctica.
- Up to one third of all amphibian species are at risk of extinction because of human actions, such as habitat destruction, climate change, and pollution.