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.

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

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

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.

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

All living things are made of cells. YouTube version [not as clear]: https://www.youtube.com/watch?v=gFuEo2ccTPA http://www.neok12.com/video/Cell-Structures/zX557e437058005b55616773.htm

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]

There are different types of cells in multicellular organisms.

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.

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

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.

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

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

Other Organs

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

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

Other Organ Systems

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.

Cell Tissue Organ Organ System Organism

Levels of Organization

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

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