1. Chapter 2
Living things

2. Section 1: What is life (Part 1, pages 34-37)
Organism = LIVING THING
Examples: yourself, a pet, insects, plants
ALL LIVING THINGS SHARE THESE CHARACTERISTICS:
Cellular organizations
Contain similar chemicals
Use energy
Respond to their surroundings
Grow and develop
Reproduce

3. Cellular Organization
All organisms are made of small building blocks called cells
A cell is the basic unit of structure and function
Cells are so small you need a microscope to see them
Unicellular: single-celled organisms (Bacteria)
Multicellular: composed of many cells that are specialized to do certain tasks
Example: in our body, muscle and nerve cells (work together to keep us alive!)

4. The Chemicals of life Cells are composed of chemicals SUCH AS…
Water (most abundant)
Carbohydrates (energy)
Proteins and lipids/fats (building materials)
Nucleic acid : genetic materials, chemical instructions that direct the cell’s activities

5. Energy Use
Cells of organisms use energy to do what living things must do
Example: Repairing injured parts
An organisms cells are ALWAYS hard at work

6. Response to surroundings
Plants and all other organisms react to changes in their environment
STIMULUS: a change in an organism’s surroundings that causes an organism to react
Example: temperature, light, sound….
RESPONSE: an action or change in behavior
Example: A plant stem growing toward the sun. Stimulus?? Response??

7. Growth and development
Living things GROW (getting larger) and DEVELOP
Development: the process of change that occurs during an organisms life to produce more complex organisms

8. Reproduction
Organisms have the ability to reproduce, or produce offspring that are similar to the parents
Example: Robins lay eggs… that develop into young robins… that closely resemble their parents!

9. Life Comes from life
Living things arise from living things through reproduction
….But, four hundred years ago people believed that life could appear from nonliving things… CRAZY!?!?!
They called this… SPONTANEOUS GENERATION
***the mistake idea that living things can arise from nonliving sources

10. Redi’s Experiment Francesco Redi – Italian doctor (1600’s)
He designed a CONTROLLED EXPERIMENT to show flies do not arise from decaying meat
Who remembers what a controlled experiment is???
A scientist carries out 2 tests that are identical in every respect except for one factor

11. Redi’s Experiment Left jar = UNCOVERED Right jar = COVERED
Manipulated Variable?
Whether or not the jar
Was covered

12. Pasteur’s experiment Louis Pasteur--- French chemist (mid-1800s)
Some people still did not believe Redi… so Pasteur came up with a new experiment
His experiment… demonstrated that new bacteria appeared in broth only when they were produced by existing bacteria
Both experiments convinced people that LIVING THINGS DO NOT ARISE FROM NONLIVING MATERIAL

13. Pasteur’s experiment