Multicellular Organization

ObjectivesDescribe cell specialization

List the levels of organization in living multicellular organisms

Unicellular OrganismsThese 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 cellsWhite blood cellsBone cellsMuscle cells

Specialized Plant Cells

An example would be Guard CellsThese regulate gas and water

flow from leaves

Levels of OrganizationsCells

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

ReviewDescribe 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 organismsTissuesOrgansOrgan System