Many species lay their eggs in calm water amongst vegetation where the eggs can develop in relative safety. The female frog lays numerous eggs in masses that tend to clump together (these egg masses are referred to as spawn). As she deposits the eggs, the male releases sperm onto the egg masses and fertilizes the eggs.
In many species of frogs, the adults leave the eggs to develop without further care. But in a few species, parents remain with the eggs to look after them as they develop. As the fertilized eggs mature, the yolk in each egg splits into more and more cells and it begins to take on the form of a tadpole. Within one to three weeks, the egg is ready to hatch, and a tiny tadpole breaks free of the egg.