1. What is Life?
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2. What is Life? What do you think of when you think of life?
Questions: What is life?
How do we define something as “living”?
What are the characteristics of living things?
Where do living things come from?
What do living things need to survive?

3. Living or Not?

4. Characteristics of Living Things
Cellular Organization
All living things are composed of cells
Unicellular or Multicellular.
Chemicals
Proteins, Lipids, Carbohydrates, Nucleic acid
Metabolism
Consumption of energy for activity, development, and maintenance.
Reaction
Responds to stimulus from the environment.
Growth & Development
Reproduction – copying one’s genetic information to create new organisms.

5. Life comes from Life
Spontaneous generation: The idea that life spontaneously appears under the right conditions.
Ex) Stale bread grows mold.
This theory was disproven by two famous experiments.
Redi’s Experiment Pasteur’s Experiment

6. Redi’s Experiment

7. Pasteur’s Experiment
Experiments

8. Needs of Living Things Water: 66% of your body is water!
Food: provides energy for activity, growth, and maintenance
Autotrophs: make their own food.
Heterotrophs: eat other organisms for food.
Living Space: room to move around and find food.
Companionship! – most animals live in groups and communicate with friends and mates.
Stable internal conditions: Body temperature, water levels, and blood sugar are internal conditions that must be kept stable even if the environment changes.

9. Resources & Competition
Living things require resources to survive, but resources are limited. This leads to competition!
Interspecies Competition
Intraspecies Competition