Unicellular VS Multicellular Life Unicellular onecelled organisms Multicellular

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

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 role

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

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.

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

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