1. I can…explain the experiments that prove “Life comes from Life” Get out your homework to be checked. Write down tonight’s homework. Warm Up: What are the 6 characteristics of life?

2. 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 http://www.youtube.com/watch?v=WNByRghR6sw

3. 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

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

5. 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

6. Pasteur’s experiment

7. Chapter 2: Living Things Section 1, Part 2

8. The needs of living things All living things need ----- Water Food Living space Stable internal conditions

9. water All living things NEED WATER TO SURVIVE. WHY? Organisms need water to… Obtain chemicals from their surroundings Break down food Move substances within their bodies Reproduce

10. Food Organisms use FOOD AS THEIR ENERGY SOURCE. Plants: Capture the sun’s energy and use it for food Organisms that make their own food are called AUTOTROPHS Examples: grass, moss, algae, trees, flowers… Organisms that CANNOT make their own food are called HETEROTROPHS Examples: animals, mushrooms, and slime molds…

11. Living space All organisms need a place to live Its surroundings MUST PROVIDE WHAT IT NEEDS TO SURVIVE How do trees compete for space? Top of the trees for SUNLIGHT Below the ground for WATER AND NUTRIENTS Come up with an example on your own!

12. Stable internal conditions Organisms must be able to keep conditions inside their bodies STABLE, EVEN WHEN CONDITIONS IN THEIR SURROUNDINGS CHANGE SIGNIFICANTLY. This is called….. HOMEOSTASIS Example: Your body temperature stays steady even when there are changes in air temperature.