Needs and Survival of Living Things

1. Needs and Survival of Living Things Life Processes

2. What Does it Mean to be ALIVE? • Any living thing is called an Organism • Organisms vary in size from a microscopic bacteria to a gigantic tree • All organisms have similar life processes that determine what it means to be alive

3. Common Life Processes for all organisms • All organisms are made up of small units called cells • Some organisms are only made of one cell (unicellular) and some organisms are made of many cells (multicellular)

4. Common Life Processes for all organisms • All organisms respond to their surroundings or respond to stimuli • Anything that causes some change in an organism is a stimulus • The reaction to the stimulus is the response • For example a cat runs to its tuna plate of food once it smells tuna. The stimulus here is the smell of tuna and the response is the cat running • In what are other ways do living things respond to stimuli?

5. Response to Stimuli

6. Common Life Processes for all organisms • All organisms use energy • The energy used by most organisms come either directly or indirectly from the sun • Plants directly use sunlight energy to make their own food • Humans eat food as a source of energy • Some bacteria use chemicals as a source of energy

7. Common Life Processes for all organisms • All organisms grow • Growth in multicellular organisms like a puppy is due to an increase in the number of cells • Growth in unicellular organisms is due to an increase in the size of the cell • The length of time an organism is expected to live is its life span

8. Common Life Processes for all organisms • All organisms reproduce • They make more of their own kind • Without reproduction, living things would not exist to replace those individuals that die

9. Common Life Processes for all organisms • All organisms exchange gases • Plants use carbon dioxide to make food • Humans breath in oxygen, and breath out carbon dioxide

10. Common Life Processes for all organisms • All organisms need water to survive • Plants need water to make food • Fish need water to breath • Some organisms need water to reproduce

11. Common Life Processes for all organisms • All organisms eliminate wastes