1. Unicellular VS. Multicellular Life
Unicellular – one-celled organisms
Multicellular – organisms that consist of many cells that work together

2. Unicellular Advantages
Self-contained – everything needed for life within single cell
Replication can be as simple as the cell copying its DNA and splitting in two
Disadvantages
Severe limitations on size of organism
Small size limits its role

3. Multicellular Advantages
Cell specilaization – cells that do a specific job for organism
Greater size – more mobility, easier to catch food, better defense
Greater diversity
Disadvantages
Greater size requires greater resources
All cells must reproduce for growth to occur
Life requires a cooperative balance between all cells in organism

4. Cell Specialization
Cells in the organism develop in different ways to perform different tasks.
EX: Nerve cells have a different function in your body than muscle cells.
Root cells in plants do a different job than leaves in plants.
EVERY CELL has a complete set of identical DNA. They contain the genetic information for the entire organism.

5. Levels of Organization
Cells
Tissues – made up of similar cells
Organs – made up of different tissues that work together
Organ Systems – A group of organs that work together to perform a specific function

6. Evolution of Multicellular Life
Unicellular organisms live and work together in colonies
Colonies, like Volvox, are colonies of individual organisms but they have developed specialized reproductive cells
In multicellular organisms, different cells become specialized and must work with other cells to sustain life