2. CELL HISTORY ROBERT HOOKE (England) 1665 observes slice of cork (bark from oak tree) with a 30X microscope Noticed “tiny boxes” in cork Called them “CELLS”

3. CELL HISTORY ANTON VAN LEEUWENHOEK (Netherlands) Creates a microscope from polished sand- 300 X Observes “clear” pond water Notices a world of tiny organisms- called them ANIMALCULES (actually single celled protists) First to see living cells- 1675

4. CELL HISTORY MATTHIAS SCHLEIDEN &THEODORE SCHWANN (Germany 1839) SCHLEIDEN- plants made of cells SCHWANN- animals made of cells Put it all together= Every living thing is composed of cells

5. CELL HISTORY RUDOLPH VIRCHOW- Germany 1855 Observed that cells come from other cells

6. THE CELL THEORY All of this information led to the CELL THEORY 1) All living things are composed of one or more cells 2) Cells are the basic units of structure and function of organisms 3) Cells come from the reproduction of existing cells

7. CELL SIZE Are elephant cells larger than ant cells?

8. NO the small size allows materials to reach all cell parts the surface area of the cell must be able to supply raw materials volume will increase faster than surface area

9. Surface area : Volume Surface area is area on surface of object- area of all sides Volume is amount of space in an object Cells want to maximize this ratio Have a large enough surface area while keeping volume small