Download Diversity of Cellular Life College Biology Mr. Lee Room 320

 Multicellular Organization
Objectives
 Describe cell specialization
 List the levels of organization in living
multicellular organisms
Unicellular Organisms
 These are single
cell organisms
 Unicellular
organisms
dominate the
Earth
Multicellular Organisms
 These organisms
are made up of
many cells
 Cell specialization
is the process how
cells develop in
different ways to
perform different
tasks
 first microscopic life (3.6
bya)
 first oxygen appears in
atmosphere (1.9 bya)
 first multicellular life (900
mya)
 first land plants appear (450
mya)
 formation of the Atlantic
Ocean begins (150 mya)
 formation of the Himalayas
begins (30 mya)
Evolution of Multicellular
Organization
 Simple prokaryotes were the first
type of life on Earth
 Single cell eukaryotes evolved next
 Some of these began to form into
colonies, like the Volvox
 From these colonial organisms,
multicellular eukaryotes evolved
Specialized Animal Cells
 Examples include:
 Red blood cells
 White blood cells
 Bone cells
 Muscle cells
Specialized Plant Cells
 An example would be Guard
Cells
 These regulate gas and water
flow from leaves
Levels of Organizations
 Cells
 Tissues- a group of
similar cells that
perform a
particular function
 Organs- many
groups of tissues
that work together
 Organ System-
group of organs that
work together to
perform a specific
function
Review
 Describe cell specialization
 Cell specialization is the process how
cells develop in different ways to perform
different tasks
 List the levels of organization in living
multicellular organisms
 Tissues
 Organs
 Organ System