Form Follows One Function: Survival
If you study animal anatomy and physiology, you will see that many creatures have found different ways to absorb oxygen from the air/food from the surroundings and ensure that their bodies have the optimum temperature. Even the development into adults can
The study of animals is always conducted in a series of specific stages. When scientists have identified the animal and its numbers, the next step is to determine its make-up (anatomy) and functions (physiology). Both scientific disciplines have a long and extensive history, which dates back to Greek and Roman natural scientists or perhaps even further.
An animal registers and coordinates information from the outside world and controls its body via its sensory organs, nervous system, and hormone system. In some creatures such as water fleas, the system is very simple. They have one single primitive eye that only knows the difference between light and darkness. Other animals have more complex sensory organs and nervous systems, that can register a very high number of different data about the outside world.
The absorption of nourishment and elimination of waste products are carried out by the digestive system. In principle, it is very simple, but as animals can eat such different things as wood, feathers, and blood, there is major individual variation.
Small animals can absorb oxygen thorough their surfaces, whereas large animals must have a respiration system with lungs, gills, or the like to absorb oxygen from air or water.
All animals are equipped with a type of reproductive system, whether they mate, carry out parthenogenesis, or just divide in two or bud off from the parent.