1. What is Life?

2. Organisms = Living things

3. How do we know that something is a living thing?

4. Characteristics of Living Things
Have a cellular organization
Contain similar chemicals
Use energy
Respond to their surroundings
Grow and develop
Reproduce

5. Have a cellular organization

6. How many cells are in this picture?
A cell is a basic unit of structure and function in an organism
How many cells are in this picture?

7. Multicellular Unicellular
Organisms composed of many cells.
These cells are specific and programmed for specific jobs.
Single celled organism.
Bacteria
Amoeba

8. Contain similar chemicals

9. The Chemicals of Life
Carbohydrates
Proteins
Lipids
Nucleic Acids

10. Water is necessary for life. If there is no water…there is NO life.

11. Get broken down into sugar (glucose).
Carbohydrates
Main source of energy.
“Starches”
Get broken down into sugar (glucose).

12. Proteins Help cells to build things. Muscle is made of protein.
Protein is found in eggs and meat.

13. Lipids Help cells to build things.
Fats and oils are lipids…sounds gross but you really need it!

14. Nucleic Acids Create genetic material DNA (deoxyribonucleic acid).
The blueprint instructions for cells to direct all activity.

15. Use energy

16. Cells in organisms use energy to function.
The students in this photo are using energy to learn. Even on the cellular level that we can’t see!

17. Respond to their surroundings

18. Clearly, this cat is responding to something that has scared it.
All living things can respond to their environment
A stimulus is what causes the organism to react.
A response is what action happens as a result of a stimulus.

19. Grow and Develop

20. Living things can grow an develop.
Development is the process of change that occurs during and organism life to produce a more complex organism.

21. Reproduce

22. All living things can produce offspring similar to themselves.

23. Spontaneous generation
The idea that life can come from a non-living source.
This was a very popular idea during the time of Francesco Redi.
He created a controlled experiment to test if spontaneous generation was real.

24. Redi’s Experiment This is a controlled experiment.
What is the control group? What is the variable group?

26. Life does not occur spontaneously.
What is the conclusion?
Life does not occur spontaneously.
LIFE COMES FROM LIFE.

27. Louis Pasteur
Wanted to re-test to see if spontaneous generation was true. (Most people still believed in it)

28. Pasteur’s Experiment This is also a controlled experiment.
What is the control group? What is the variable group?

30. The Needs of Living Things
Food
Autotroph – make their own food
Heterotrph – must consume others
Water
All organisms need water to survive.
Living
Space
All organisms need a place to live – there is limited space on Earth.

31. The maintaining of a stable internal condition.
Homeostasis
Homeostasis = Balance
The maintaining of a stable internal condition.

32. How does this frog maintain homeostasis?