1. Multicellular Organization

2. Objectives Describe cell specialization List the levels of organization in living multicellular organisms

3. Unicellular Organisms These are single cell organisms Unicellular organisms dominate the Earth

4. 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

5. 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)

7. 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

8. Specialized Animal Cells Examples include: Red blood cells White blood cells Bone cells Muscle cells

9. Specialized Plant Cells An example would be Guard Cells These regulate gas and water flow from leaves

10. 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

11. 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