External fertilization is characterized by the release of both sperm and eggs into an external environment; sperm will fertilize the egg outside of the organism, as seen in spawning.

Internal fertilization is characterized by sperm fertilizing the egg within the female.
Both egg and sperm are used during this process.

Internal fertilization affords the species a better chance of reproductive success by protecting the sperm and egg from external predation. Internal fertilization cuts down on excessive sperm and egg amounts

External fertilization can fertilize larger quantities leading to more offspring. Thus, resulting in less competition for resources.

Internal And External Fertilization