These animals are often confused, so they are treated together. “Amphibian” comes from the Greek amphi, meaning “both,” and bios, meaning “life.” It has two meanings. First, the animals physically change. Reproduction is accomplished through external fertilization. The female spawns her eggs in water where they are fertilized by the male. After hatching, most amphibians undergo a dramatic change known as metamorphosis. They slowly change from fishlike, water-dwelling animals to ones better suited for life on land. Fins and gills become legs and lungs. The most well-known example is the change from tadpole to frog. Second, the term also refers to these animals first living in the water and later on land.
Reptiles reproduce by sexual intercourse and internal fertilization, just like mammals. Amniotic eggs develop within the mother’s abdomen. Once they are sufficiently developed, the mother lays them and they hatch. However some reptiles give birth to live young.