The Levels of Organization
There are five levels of life: cells, tissue, organs, organ systems and organisms
The cell is the basic unit of structure and function of a living thing.
Example 1: single celled organisms, bacteria
Example 2: white blood cells
Example 3: plant cells
Tissues are made of a group of similar cells that work together to do a specific job in the body.
Example 1: muscle tissue
Example 2: scar tissue
Example 3: Connective tissue
Organs are made up of two or more tissues that work together to do a specific job.
Example 1: the heart
Example 2: the liver
Example 3: the brain
An organ system is a group of organs working together to perform particular jobs.
Example 1: the respiratory system
Example 2: the digestive system
Example 3: the nervous system
Sum of all cells, tissues, organs and organ systems makes an organism. An organisms is made when a group of organ systems work together.
Example 1: flowers
Example 2: people
Example 3: animals
All of the systems work together to create life. The cells are what the organs are made of, without them there would be no organs and without organs there would be no organ systems. If any one of these systems were missing the entire organism would not work.