Amphibia

Amphibians are a class of ectothermic vertebrates that are known for their ability to live both in water and on land. The word "amphibian" comes from the Greek words "amphi" (both) and "bios" (life), which perfectly describes their dual existence. Most amphibians undergo metamorphosis, a transformation from a larval stage to an adult. For example, a tadpole, which lives in water and breathes through gills, transforms into a frog, which lives on land and breathes with lungs.

Their skin is typically smooth, moist, and permeable, allowing them to absorb water and oxygen directly from their surroundings. This also makes them very sensitive to environmental changes and pollutants. Amphibians include frogs, toads, salamanders, and caecilians. They are typically found in moist habitats near water, and their life cycle often depends on access to a water source for reproduction.