Levels of Organization

What is Organization?

Let's start with an analogy- Books!

Organization is not just about keeping your room tidy. In the biological world, living things have different levels of organization within their bodies.

Let's think about how books are formed. They are formed with words, letters, sentences, etc.
What is the simplest or smallest level?
What is the most complex or largest level?

Reorder

Reorder the parts of a book from the smallest (1) to largest (5) component.

• letters

• words

• sentences

• paragraphs

• chapters

1

2

3

4

5

• 1
• 2
• 3
• 4
• 5

Body Organization

​Imagine jumping into a lake. At first your body feels cold. You may even shiver. But eventually you get used to the cold water. How?

Your body gets used to the cold because it returns to homeostasis.
Homeostasis is the maintenance of a stable internal environment in the body.

When you feel cold, tiny sensors in your skin send messages to your brain telling you that you need to warm up. Your brain then sends messages to nerves all over your body telling your muscles to move, generating heat. When you jump into the lake homeostasis helps your body adapt to the cold water.

Multiple Choice

What is homeostasis?

• Balance of power
• External instability maintenance
• Internal stability maintenance
• Chaos theory

Body Organization

Cells

Remember cells are the basic unit of all living things, including yourself. Your cells do many jobs to maintain homeostasis.

But each of your cells do not have to do all of those jobs. Just as each person on a soccer team has a role during the game, each cell in your body has a role in maintaining homeostasis.

Body Organization

Cells form Tissues

Your cells are organized into groups called tissues. Tissues are a group or layer of cells that work together to perform a specific function.

For example, the muscle cells for your heart work together to make cardiac muscle tissue.

Cardiac muscle is a specialized, organized type of tissue that exists only in the heart. It is responsible for keeping the heart pumping and blood circulating around the body.

Multiple Choice

The basic unit of structure and function of living organisms

• organ

• organ system

• cell

• tissue

• organism

Multiple Choice

A group of similar cells that work together to form the same function is called .......

• organ

• cell

• organ system

• organism

• tissue

Body Organization

Tissues form Organs

One kind of tissue alone cannot do all of the things that several kinds of tissues working together can do. Two or more tissues working together form an organ.

The stomach is an organ. The four kinds of tissue shown work together so that the stomach can carry out digestion.

Multiple Choice

The heart is another major organ in our body. What is an organ made of?

• Tissues
• Blood
• Bones
• Cells

Body Organization

Organs form Organ Systems

Your stomach does a lot to help you digest food. But the stomach does not do it all. Your stomach works with other organs, such as the small and large intestines, to digest your food.

Organs that work together make up an organ system.

Multiple Choice

What are the organ systems made of?

• Tissues
• Organs
• Cells
• Blood vessels

Match

Match the following levels of organization to their correct description.

• smallest unit of living things

• a group of similar cells that perform a common function

• a collection of tissues that carry out a specialized function of the body

• a group of organs that work together to perform body functions

cell

tissue

organ

organ system

• cell

• tissue

• organ

• organ system

Body Organization

​Organ Systems form Organisms

Finally, every organ system comes together to create the organism.

There are 11 organ systems in the human body.
**Not all of them are shown here.

​Complexity changes at each level

Reorder

Reorder the following parts of the body from the simplest (1) to most complex (4) level.

• cells

• tissues

• organs

• organ systems

1

2

3

4

• 1
• 2
• 3
• 4

Categorize

Options (8)

heart

circulatory system

a group of organs with related functions working together to perform body functions

the basic structural and functional unit of all living organisms

a group of similar cells that work together to perform a specific function

a group of tissues that work together to perform a specific function

smooth muscle

Organize the pictures and descriptions into the correct level of organization. Every level will have one picture and one definition.

cells

tissue

organ

organ system