1. Structural Support and Protection:
* Bones: The skeletal system provides structure, support, and protection for vital organs in many animals. Bones are made of calcium phosphate and other minerals.
* Cartilage: Provides flexible support, found in joints, ears, and noses. Composed of collagen and other proteins.
* Chitin: A tough, flexible, and waterproof substance that forms the exoskeletons of insects, crustaceans, and other arthropods.
* Skin: The outer layer of an animal's body provides protection from the environment, regulates temperature, and can be involved in sensory functions. Made of collagen, elastin, and other proteins.
2. Movement and Locomotion:
* Muscles: Muscles attach to bones (or other structures) and contract to allow movement. Composed of protein filaments like actin and myosin.
* Ligaments: Tough, fibrous tissues that connect bones to other bones, providing stability to joints. Made of collagen.
* Tendons: Strong, fibrous tissues that connect muscles to bones, allowing muscles to transmit force to the skeleton. Made of collagen.
3. Internal Functions:
* Blood: Circulates throughout the body, transporting oxygen, nutrients, and waste products. Composed of plasma, red blood cells, white blood cells, and platelets.
* Organs: Groups of tissues working together to perform specific functions. For example, the heart pumps blood, the lungs exchange gases, and the kidneys filter waste.
* Nerves: Transmit signals throughout the body, allowing animals to sense their environment and respond accordingly. Composed of neurons and glial cells.
4. Other Important Materials:
* Water: Essential for all living organisms, used for hydration, transport, and many metabolic processes.
* Nutrients: Animals obtain nutrients from their food, which are broken down and used to fuel growth, repair, and other bodily functions.
* Hormones: Chemical messengers produced by the body that regulate various physiological processes, like growth, development, and metabolism.
It's important to remember that the specific materials and their proportions can vary greatly between different animal species, depending on their size, lifestyle, and environment.