Frogs are a good example of r-selected organisms. Frogs lay many eggs and leave them in the water to hatch into tadpoles. Some of the eggs get eaten, and many of the little tadpoles are eaten, too, by dragon-fly larvae and fishes and fishing birds. But frogs go on because they lay so many eggs. Elephants are examples of K-selected animals.
Female elephants have babies about three years apart, and they have only one each time.
The whole group looks after the youngsters, and protects them through childhood and adolescence. By reproducing at a rate that holds their numbers close to constant, elephants are able to survive in stable ecosystems. Because they ensure the survival of a good percentage of their young, elephants do not need to produce many elephant babies. Let's look at the impact of human activities on these two reproductive strategies. R-selected species Human activities have had a powerful impact on the environment.