1. 4.3 Multicellular Organization p.86-88
Cells of multicellular organisms are specialized to do certain jobs.
Red blood cells carry oxygen to other cells
Muscle cells contract for motion
Function is related to shape and organelles present
More complex than unicellular
What was the term for cells developing to do different jobs?

2. Metabolic waste products (nitrogenous waste)
Fig. 40-4a
External environment
CO2
Food O2
Mouth
Animal
body
Respiratory
system
Blood
Nutrients
Cells
Heart
Circulatory
system
Interstitial
fluid
Digestive
system
Excretory
system
Anus
Unabsorbed
matter (feces)
Metabolic waste products
(nitrogenous waste)

3. 4.3 Multicellular Organization p.86-88
Cells ↓ Tissues Organs Organ systems Organisms
Can I pick a cell in the body and work it up to the organism?
Can I pick an organ system and work it down to the cells?

4. 4.3 Multicellular Organization p.86-88
Cells
(cardiac cells) ↓
Tissues
(cardiac muscle)
(heart)
Organs
(circulatory system)
Organ systems
Organisms
(humans)
Can I pick a cell in the body and work it up to the organism?
Can I pick an organ system and work it down to the cells?

5. Fig. 40-5m
Nucleus
Intercalated
disk
50 µm
Cardiac muscle

6. 4.3 Multicellular Organization p. 86-88
How might have multicellular organisms evolved?
Unicellular organisms form colonies
Individual cells in the colonies begin to specialize (differentiation)
Colonies of unicellular organisms evolve into simple multicellular organisms
Supported in fossil record
What other ways might have multicellular organisms evolved from unicellular?
(think different kinds of organisms)

7. 4.3 Multicellular Organization

8. 4.3 Multicellular Organization

9. 4.3 Multicellular Organization