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?

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)

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?

4.3 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?

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

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)

4.3 Multicellular Organization

4.3 Multicellular Organization

4.3 Multicellular Organization