The diagram illustrates the developmental phases that a frog passes through during its life time.
Overall, a frog passes through eight stages which start with adult frogs mating and eggs laid in the water from which tadpoles emerge. Tadpoles pass through a number of stages before becoming a froglet, a young frog and finally an adult frog, starting the life cycle again.
Initially, adult frogs mate and then the female frog lays eggs in the water, which are called frogspawn. Seven to ten days later, tadpoles emerge from the eggs which can swim and eat algae for food. Six weeks later, the tadpole grows and develop back legs. This development continues and nine weeks later it develops front legs. It’s head and body also becomes more pronounced.
Twelve weeks after the tadpole stages, it becomes a froglet which resembles a small frog. However, it still has a tail, although shorter than that of a tadpole. At this stage, it also develops pulmonary breathing which enables it to leave the water and breathe air on land. Over time, the froglet becomes a young frog and eventually, four years later, it is an adult frog ready to start the life cycle again.