Water is essential to life. Liquids, mostly water, make up 70 to 90% of all living systems, and the loss of even a small percentage can mean the difference between life and death. Living systems must maintain a proper liquid balance, which is especially difficult in dry conditions. To do so, they must control the movement of liquids across their boundaries. Living systems do this using structures or waterproof materials to prevent or slow liquid movement. For example, when humans receive a cut, they must limit blood loss. Scattered throughout the bloodstream are lens-shaped structures that serve to plug the wound.
Kingdom Animalia (“having breath or soul”): Mammals, reptiles, sponges, corals, insects, birds
This kingdom captures a staggering variety of life—from the smallest coral polyp to the largest elephant. Although animal body shapes and life histories vary, there are a few defining characteristics. Animals are heterotrophs, meaning they gain energy from eating other organisms, and have developed from single-celled ancestors to highly diversified and coordinated multicellular forms. Unlike plant and fungi cells that have rigid cell walls, animal cells are bound by more flexible combinations of proteins. Most animals have cells organized into tissues and are able to move within their environment.
Some nematodes survive drought conditions by entering an ametabolic state known as anhydrobiosis.
“Some nematodes, or round worms, undergo a similar, though less profound, form of cryptobiosis. As demonstrated by Newcastle University researcher Prof. Conrad Ellenby during a series of classic experiments, they become wholly desiccated when confronted with unfavorable external conditions, yet they revive fully when moistened.” (Shuker 2001:113)
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