Amphibians and their habitats biology lesson for kids: 1st, 2nd, 3rd, 4th, 5th, 6th and 7th grades biology lesson.
Amphibians are a cold-blooded class of vertebrates (animals with backbones) that have four legs. They live in many different kinds of environments, but they have something very unique in common: most of them start off as babies that swim in water, and change over time to adult forms that usually spend much if not all of their time on land. Some examples of amphibians are frogs, toads, and salamanders.
There are lots of different types of amphibians. We all know frogs and toads. There are also salamanders, which are amphibians, too, even though they look like lizards. Some amphibians are even legless!
When an amphibian hatches from its egg, it is a tadpole. They look a lot like fish because each one has gills and a flat tail that they use to swim. As they eat and grow, they their bodies change. They start growing legs and eventually lose their gills. That is why they’re called “amphibians”, which means “living two lives”: they live their first “life” in the water, then move on to live their second “life” on land. The change that they go through from tadpole to adult is called metamorphosis.
When the metamorphosis is finished, amphibians leave the water and start walking (or hopping, as frogs and toads do) on land. Not all amphibians lose their gills, though. Some types of salamanders keep their gills throughout their lives, so they breathe under water more easily. Most amphibians develop lungs as they lose their gills, so they can breathe air, but since amphibians skin is usually very moist, it makes it easier for them to breathe through their skin since oxygen can dissolve in their mucous layer and pass through their skin. This process is so effective that some amphibians don’t develop lungs at all!
Even though they’re the same species as their parents, most tadpoles eat algae and plants. When they grow up, they might eat insects, worms, slugs, snails, or small fish. That is a good thing, because it means babies and adults don’t compete for the same types of food.
Amphibians tend to live close to the water, or in very wet places. It isn’t easy to maintain their skin moisture in places that are too dry. Living near water is also good because it makes it easier to find a place to lay their gelatinous eggs, which usually need lots of water to stay healthy. And, of course, their tadpoles need water, too.