1. Introduction to Life Science
What is Life?

2. Section 1 Is it Alive? An organism is an individual form of life.
Biologists often use five basic rules to classify something as living or nonliving.
Yeast is a living organism.
Each tiny sphere is an individual living thing.

3. Characteristics of Living Things
All living things respond to a stimulus. The sunlight is a stimulus and the frog’s choice to sun himself is called a response.
All living things take materials from their surroundings such as food, water, and gases and use these materials to get energy.
Growth refers to an increase in mass and to an increase in number of cells.
The process of making more of the same kind of organism is called reproduction.
A cell is the smallest unit of a living thing.

4. What Characteristics do all Living Things Share?
All living things have a cellular organization.
A cell is the basic unit of life.
Unicellular- one celled
Multicellular- more than one cell

5. 2. Cells are composed of chemicals.
Water- the most abundant
Carbohydrates- for energy
Proteins and lipids- building materials
Nucleic Acids- contain genetic material

6. 3. All living things use energy.
Energy is used to nourish, repair and create new cells.
We obtain energy from converting the foods that we eat into energy that can be used by the cells.

7. 4. Living things react to stimuli.
A stimulus is something in the environment that causes a reaction, or a response.
A response is an action or change in behavior.

8. 5. Living things grow and develop.
Growth- an increase in the size of an organism.
Development- a progressive change in an organism over time.

9. 6. All living things have the ability to reproduce.
All living things arise from other living things.
The theory of Spontaneous Generation, which proposed that life can appear spontaneously from non-living things, was disproved by experiments performed by Redi and Pasteur.

10. Life Comes from Life Living things come from living things.
400 years ago people thought that living things came from non-living things (Spontaneous Generation).
Francisco Redi, Louis Pasteur did experiments to disprove this theory.

11. Redi’s Experiment

12. What do All Living Things Need to Survive?
Water****
Food
Living space
Stable internal conditions (Homeostasis)

13. How do Organisms Obtain Food for Energy?
Autotrophs- make their own food (Plants).
Heterotrophs- obtain food from other sources.
Herbivore- eat plants.
Carnivore- eat animals (meat).
Omnivore- eat plants and animals.

14. All living things will die.
One of the realities of life is that all life eventually comes to an end. This process is called Expiration.

15. Is it alive????? You be the judge based on our definitions………….

16. Do Now!
Read Chapter 2 Section 1, pages and complete the What is Life? Review and Reinforce Worksheet. Due Thurs 9/25