Excretory and reproductive systems each have important but different functions in animals. The excretory system maintains water, ion, and nitrogen balance within the body and eliminates wastes. The reproductive system creates new individuals of a species. Both the excretory and reproductive systems are under endocrine control but are also influenced by the external environment.

The Reproductive System

The reproductive system functions to produce more individuals of a species. The reproductive system is regulated by the endocrine system and is affected by environmental conditions outside of the animal and internal conditions inside the animal. Reproductive cycles are influenced by the time of year, amount of daylight and rainfall, and temperature, in addition to nutrition and general health of the animal.

The main organs in the reproductive system are the gonads, which include the ovary and testis. The ovaries produce eggs and the testes...