1. Essential Question:
How do cells, tissues, organs, and organ systems explain the complexity of living things?
Standard: S7L2c. Explain that cells are organized into tissues, tissues into organs, organs into systems, and systems into organisms.

2. Let’s Review
Turn to a seat partner and discuss the characteristics of living things.

3. Which of the following are living?
Grass
Fire
Coal
Mushroom
Bacteria
Gold

4. Activating Strategy: Look at the two living organisms below
Activating Strategy: Look at the two living organisms below. What makes organism A more complex than organism B?
Organism A
Organism B
Organism A is a multicellular organism. Organism B is a paramecium which is unicellular. Today’s lesson will examine some of these differences.

5. Use the Levels of Organization Notes Organizer to take notes [put organizer together using teacher directions]
Pages of the Organizer should be stapled together as sort of a flip book

6. All living things are made of cells.
YouTube version [not as clear]:

7. Facts about Cells The cell is the smallest unit of a living thing.
Some organisms are made of a single cell [unicellular like Organism B in the previous slide]
Some organisms are made up of many cells [multicellular like Organism A in the previous slide]
Each cell whether part of a unicellular organism or a multicellular organism performs all the activities that characterize life.
Multicellular organisms are more complex than unicellular organisms [the horse is a more complex organism than the paramecium]

8. There are different types of cells in multicellular organisms.

9. Cells in a multicellular organism are specialized.
Muscle Cell
Cells in a multicellular organism are specialized.
The ways in which the cells work together and interact depend on the organism.

10. Draw a simple illustration of a cell in your notes organizer.
Write Facts about Cells
Draw a simple illustration of a Cell

11. Muscle Tissue
In more complex organisms, cells are not only specialized but grouped together in tissues.
A tissue is a group of similar cells that are organized to do a specific job.

12. Draw a simple illustration of a tissue in your notes organizer.
Write Facts about Tissue
Draw a simple illustration of a Tissue

13. Different tissues working together to perform a particular function represent another level of organization, the organ.
The Heart

14. Other Organs

15. Draw a simple illustration of an organ in your notes organizer.
Write Facts about an Organ
Draw a simple illustration of an Organ

16. The Circulatory System
Different organs and tissues working together form an organ system. An organism may have only a few organ systems.

17. Other Organ Systems

18. The organism itself represents the highest level of organization.
If an organism is complex, it will consist of trillions of cells grouped into tissues, organs, and organ systems.
If an organism is simple, it meets its needs with a body made up of only a few types of specialized cells.

19. Cell
Tissue
Organ
Organ System
Organism

20. Levels of Organization

21. Optional Review Activities [see resources]
Levels of Organization Sort
Levels of Organization Review
Onion and Cheek Cell Lab or view microscope slides of cells

22. Summarizing Strategy
Which of the following shows the correct representation of the levels of organization in a multicellular organism?