2. The Characteristics of Living Things  Biologists use six characteristics to classify something as a living thing. 1. Made of Cells 2. Use and Need Energy 3. Adapted to Their Surroundings 4. React to Changes 5. Reproduce 6. Grow and Develop

3. The Characteristics of Living Things §All living things have these six characteristics. §Anything without one of these six characteristics is nonliving. §Living things are called organisms.

4. 1. Made of Cells §Organisms are made up of one or more cells. §A cell is the basic unit of structure and function in living things. l Cells = the of life.

5. 2. Use and Need Energy §All organisms need and use energy to live. §Energy is the ability to do work.  Sunlight is the source of energy for most living things. l Plants use the energy in sunlight to make food, and animals get energy by eating plants or other animals that have eaten plants.

6. 3. Adapted to Their Surroundings §Organisms are adapted, or suited, to their surroundings.  All organisms have features that help them survive in their surroundings. l For example: fish have gills

7. 4. React to Changes  Organisms react to change in their surroundings.  Any reaction to change is called a response. l For example: A bright light may cause you to blink.

8. 5. Reproduce §Organisms produce more organisms of their own kind. §Reproduction allows organisms to continue living on the earth.

9. 6. Grow and Develop  Living things change, or develop, during their lifetimes. l One way organisms change is by growing. Living things may also change in appearance. For example: tadpoles and frogs §All organisms grow and develop.

10. Summary  Biologists use six characteristics to classify something as a living thing. 1. Made of Cells 2. Use and Need Energy 3. Adapted to Their Surroundings 4. React to Changes 5. Reproduce 6. Grow and Develop §All living things display all of the above characteristics.

11. Symbiosis §Close relationship between two species in which at least one species benefits from the other §Live together for LIFE

12. Parasitism §Bacteria exploit the host cell, injuring them §Eg. Mychobacterium tuberculosis

13. Mutualism §Symbiosis in which two of the species live together in such a way that both benefit from the relationship §Eg. E-coli

14. Nitrogen Fixations §Process by which nitrogen in the atmosphere is converted into a form that can be used by living things