Summary
Vertebrates such as frogs that typically begin life in water and live on land as adults.
In depth
Moist permeable skin used for gas exchange, three-chambered heart, aquatic eggs and larvae in many species. Orders: frogs and toads, salamanders, caecilians. Sensitive to pollution and disease (chytrid fungus), so they are bioindicators.
Amphibian skin is moist, needing damp habitats. Many have biphasic life cycles. Declines from disease and habitat loss are severe.
Key idea: frogs, salamanders and caecilians are the three groups.
Amphibians (about 8000 species) include frogs, salamanders and caecilians. Skin must stay moist and is used for gas exchange and absorbing water, which makes them vulnerable to pollutants and indicators of environmental health. Most have a biphasic life: aquatic gill-breathing larvae (tadpoles) that metamorphose, regulated by thyroid hormone, into lunged adults, though some, like axolotls, remain larval (neoteny) and some are direct developers.
Amphibians are the most threatened vertebrate group, with about 40 percent of species at risk due to habitat loss, pollution, climate change and the chytrid fungus. Poison dart frogs sequester alkaloids from their diet. Salamanders show impressive regeneration.
Remember: the three-chambered heart of amphibians mixes blood partially, which is sufficient for their metabolic rate.
Frequently asked questions
What is Amphibians?
Vertebrates such as frogs that typically begin life in water and live on land as adults.
Which area of biology covers Amphibians, and how advanced is it?
Amphibians is one of the 53 topics in Zoology & Animal Diversity. It is rated Beginner, so it suits learners who are starting out in biology. Related topics in this area include Fish, Insects, Metamorphosis.
Can you give an example of Amphibians?
Tadpoles of frogs have gills and tails.
What should I learn before Amphibians?
Amphibians is a Beginner topic, so no earlier topic is required. Other Beginner topics in Zoology & Animal Diversity that pair well with it include Animal Kingdom, Vertebrates and Invertebrates, Sponges.
What topics are related to Amphibians?
The closest topics to Amphibians are Fish, Insects, Metamorphosis, Animal Respiration. Comparing them side by side is a good way to see how the ideas connect.
How can I check that I understand Amphibians?
Read the summary and the in-depth section, then use the quick check on the interactive lesson for Amphibians. To practise the whole of Zoology & Animal Diversity, use the Zoology & Animal Diversity quiz.
How is Amphibians different from Fish?
Amphibians: Vertebrates such as frogs that typically begin life in water and live on land as adults. Fish: Aquatic, gill-breathing vertebrates, including jawless, cartilaginous and bony fishes. Read both side by side and note what each one explains.
How should I study Amphibians step by step?
First, read the summary and write the definition in your own words. Second, read the in-depth section and note any example. Third, compare it with Fish and explain the difference aloud. Finally, take the Zoology & Animal Diversity quiz and come back to this page for any question you miss.