Low-light eyes are sensitive to bright light and have protective features like pupils and nictitating membranes. In order to see color we need color-sensitive cells, and a brain to interpret the information they send. We think some animals see color because their eyes have color-sensitive cells and because scientists have conducted experiments to test what the animals see. The position of an animal's eyes suits its needs. Some animals have more than one type of eye.
Specialized cells perform specialized functions in multicelled organisms.
Groups of specialized cells cooperate to form a tissue, such as a muscle. Different tissues are in turn grouped together to form larger functional units, called organs. Each type of cell, tissue, and organ has a distinct structure and set of functions that serve the organism as a whole. Animal Eyes teaches these ideas by looking at the light-sensitive cells that are crucial to all types of eyes, from the simple photoreceptors of the earthworm to our own retina. Students can see diagrams and models of the various tissues that make up an eye.