Characteristics of Living Things 1. Highly organized, containing many complex chemical substances. 2. Composed of one or more cells. 3. Use energy. 4. Possess definite form and limited size. 5. Have a limited life span.

6. Grow. 7. Respond to changes in the environment/stimuli. 8. Reproduce. 9. Groups of living things evolve. Note: Most living things exhibit these characteristics, but there are exceptions. For example, mules are sterile and thus cannot reproduce.

Processes of Life Living organisms carry out a number of life processes. These processes include: 1. Nutrition: includes ingestion (taking in food), digestion (breaking down food) and egestion (food leaves the body). 2. Transport: the movement of oxygen, nutrients, water and waste products to and from cells.

Processes of Life 3. Respiration: taking in oxygen to burn food for energy. 4. Synthesis: forming new complex substances from simpler ones. 5. Assimilation: incorporation of materials into the body from nutrients found in food. 6. Growth: increase in size and number of cells. Includes repair of damaged tissues and replacement of old cells.

Processes of Life 7. Excretion: removal of wastes from organism. 8. Regulation: maintaining a stable internal environment (homeostasis) 9. Reproduction: creation of new, similar organisms. Can be sexual or asexual. 10. Metabolism: all chemical reactions that take place within the cells of an organism.