This interactive model illustrates the life cycle of a frog. Press "Run" button to initiate the animation. Press "Stop" to bring it to a halt, and press "Reset" to return the model to its initial state.
In order to procreate, a frog, like any other amphibian, needs water. Some frogs give births to live offspring, but most of them lay eggs, which are then fertilized by the male's milt. One of the spermatozoids unites with an egg cell, forming a zygote. The zygote undergoes segmentation and develops into an embryo. That embryo becomes a tadpole at a later stage. Eventually the external gills of the tadpole turn into spiracles, and he grows paws. The tail is the last vestige to go before a tadpole turns into a young frog.