Distribute Liquids
Liquids include water, as well as body fluids such as blood, gastric juices, nutrient-laden liquids, and more. To survive, many living systems must move such liquids within themselves or between locations. Because of their properties, liquids tend to disperse unless they are confined in some way. To address this, living systems have strategies to confine fluids for transport, and to overcome barriers such as gravity, friction, and other forces. Some of these same barriers also provide opportunities. Trees and giraffes face the same challenge: how to move fluids (water and blood, respectively) upward against gravity. But their strategies are quite different. The tree moves water using capillary action and evaporation, possibly due to water’s properties of polarity and adhesion. The giraffe’s tight skin provides pressure to assist in blood circulation. and keep blood from pooling in the legs.
Protect From Gases
Gases are part of most living systems’ environments, especially those exposed to the earth’s atmosphere. Two gases that can act as threats to living systems are oxygen and carbon dioxide; both, paradoxically, are also necessary to life. Thus, living systems must obtain a balance in gas concentrations, selectively protecting from too much gas in some situations and not enough in others. For example, mound-building termites protect themselves by building ventilation shafts to remove excess carbon dioxide from their fungal gardens.
