Frogspawn
The frogspawn that you see floating in ponds is made up of thousands of single eggs, each one having a tiny black tadpole embryo surrounded by jelly.
Frogs lay so many eggs because they do not look after their young, so most do not survive to adulthood. From the three thousand eggs that one female lays, only around five will become adult frogs. The rest of the eggs or tadpoles may be eaten by birds, fish, newts, water beetles or dragonflies, or simply dry up before hatching.
At first each tadpole embryo will eat the jelly that is around it until it is ready to hatch.
