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The diversity of cellular life
7.4 Biology
Mr. Hines
Unicellular organisms
Sometimes the cell is the organism.
For example, all protists and bacteria are
single celled organisms
1 cell = 1 organism
Single celled organisms are called unicellular.
Unicellular organisms dominate life on earth
(Most common and diverse)
Amoeba
•
Euglena
•
Paramecium
Colony of cells
When unicellular organisms clump together, it
is called a colony.
Cells within a colony are individual organisms
living with others.
There is no cell specialization.
Volvox
Multicellular organisms
Organims that are made of many cells are
called multicellular.
A multicellular organism will have specialized
cells which perform specific tasks for the
survival of the organism.
For example, liver cells, brain cells, nerve
cells, muscle cells, blood cells etc.
Levels of organization
Cells form tissues (layers of cells)
Tissues form organs
Organs form organ systems.
•
Hydra
•
Newt
•
Dog
•
Aye Aye
•
Just Kidding
•
What is the difference between a
colony of cells and a multicellular
organism?
A colony is made of individual organisms
living together and there is no cell
specialization.
A multicellular organism is made of
specialized cells living together that are
needed for the survival of the organism