Levels of Organization in Biology

Levels of Organization

Living things (organisms) can be categorized into one of two groups

• unicellular (made of one cell)

• multicellular (made of many cells)

Unicellular Organisms

• These organisms can complete all the processes needed to stay alive in one cell

• The processes include things like: obtaining food, making food, reproducing, and responding to their environments.

Multicellular Organisms

Multicellular organisms are much more complex and arranged in levels.

Multiple Choice

Unicellular means

• made of one cell

• made of many cells

Multiple Choice

Multicellular means

• made of one cell

• made of many cells

Multiple Choice

Bacteria, paramecium, and yeast are all examples of

• unicellular organisms

• multicellular organisms

Multiple Choice

A cow, mushroom, and tree are examples of

• unicellular organisms

• multicellular organisms

Multiple Choice

_______________ organisms are able to conduct all processes for life within one cell.

• multicellular

• unicellular

The levels of organization for multicelluar organisms from smallest to largest are

• cells

• tissue

• organ

• organ system

• organism

Level One: Cells

• Cells are the basic unit of living things

• They are specialized and have different shapes and functions

• Examples in animals are muscle cells, nerve cells, red blood cells, and white blood cells.

• Examples in plant cells are epidermal cells, guard cells, and paliaide mesophyll cells.

Level Two: Tissues

• Tissues are made up of similar cells that work together to perform a particular task

• Examples of animal tissues are blood tissue, bone tissue, and muscle tissue

• Examples of plant tissues are epidermis tissues and vascular tissues

Level Three: Organs

• Organs are made up of different tissues that perform a specific job for the organism

• Examples of animal organs are heart, brain, bone, skin, and liver.

• Examples of plant organs are roots, leaves, and stems. 

Level Four: Organ Systems

• Organ systems are made up of different organs and perform a major function for the organism

• Animal organ systems include: respiratory, circulatory, and nervours.

• Plant organ systems include: the shoot system and the root system.

Level Five: Organism

• The organism is made up of all the cells, tissues, organs, and organ systems.

• 
  

• 
  

Multiple Choice

What are the levels of organization from smallest to biggest?

• organism, organ system, organ, tissue, cell

• cell, organ, tissue, organ system, organism

• cell, tissue, organ, organ system, organism

Multiple Select

Check all the examples of organs.

• red blood cell

• bone

• leaf

• heart

• muscle tissue

Multiple Choice

A group of similar cells working together to perform a function is a

• cell

• tissue

• organ

• organ system

Multiple Choice

T or F Plants don't have organs.

• True

• False

Multiple Choice

T or F Multicellular organisms have specialized cells.

• True

• False

There are actually even more levels..........