Levels of Organization

Unicellular Organisms Single cell performs all life functions. It functions independently.

Multicellular Organisms Have various levels of organization Individual cells within the organism perform specific functions but they must also work together for the good of the entire organism The cells become dependent on each other

Multicellular Organism Organization

Level 1 Cells The basic unit of structure and function in living things Serves a specific function with organism Examples – blood cells, nerve cells, etc

Level 2 Tissues Made of cells similar in structure and function that work together to perform a task Four basic types – connective, epithelial, muscle and nervous

Level 3 Organs Made up of tissues that work together to perform an activity

Level 4 Organ Systems Groups of 2 or more organs that work together to perform a specific function for the organism Humans have 11 systems

Level 5 Organisms Entire living things that can carry out all basic life function. Usually made up of organ systems, but can be a single cell also