1. What is Life? Chapter 1, Section 1

2. Organism Any living thing Some are unicellular Some are multicellular

3. So what makes something alive? It must be made of cells –Cell – basic unit of structure and function of all organisms. –To see most single cells, a microscope is needed.

4. Living things share the same chemicals. Water is the most abundant chemical in life Other chemicals include: –Carbohydrates – an energy source –Proteins and Lipids – building materials of cells –Nucleic acids – genetic material (DNA and RNA)

5. All Living things use Energy Energy is needed to grow, repair, move, etc. Energy comes from food – either an organism makes its own food (an autotroph) or must eat other organisms (a heterotroph).

6. Organisms Grow and Develop Growth – gets larger Development – changes during lifetime Both processes need energy

7. Response to Surroundings Stimulus – a change in the environment that causes a reaction Response – the reaction to a stimulus –EX – plants grow toward light – the light is the stimulus, the response is the bending of the stem.

8. Reproduction The ability to produce offspring. Necessary for the entire group of organisms, not for each individual.

9. Spontaneous Generation Life from nonlife –Ex – mice from sweaty Shirts in a barn -maggots from meat or worms from fruit -Bacteria from soup or gravy

10. Do organisms arise by Spontaneous Generation? Spontaneous generation (SG) is life from nonlife. Francesco Redi disproved SG of maggots on meat in 1668.

11. Louis Pasteur finally disproved SG Louis Pasteur later disproved SG of bacteria in the late 1800’s. He used swan-neck flasks – how did they work?

12. What do Living Things Need to Live? Energy –Food is source for organisms –Energy in food can be traced back to the sun! –Think about what you ate at your last meal – can it all be traced back to the sun?

13. Water Water is needed to: –Get chemicals from environment –Break down food –Grow –Move substances through body or cell –reproduce

14. Living Space A place to find food and water and to be sheltered from the environment.

15. All Living Things Need a Stable Internal Environment Homeostasis – keeping conditions in the body stable, even while conditions outside the body change. –Ex – what happens to you when you drink a lot of water over a short time? –What is human body temperature?

16. The End