2. It all started with an invention….  The first microscope  Zacharias Jansen, 1595, Middleburg, Holland  It launched great leaps in Astronomy and Biology.  Some of the first great observations with it were made by…

3. Robert Hooke (1635-1703)  Designed microscopes  Discovered and documented the first “cells” in 1665  Named them after the cells in which a monk sleeps.

4. Antony van Leeuwenhoek (1632-1723)  A tradesman from Holland who became fascinated with who became fascinated with Hooke’s book Hooke’s book  Discovered bacteria, free- living protists, blood cells, nematodes, etc. living protists, blood cells, nematodes, etc.  Became an expert lens grinder and made over 500 simple microscopes  Acute eyesight and lens grinding skill let him build microscopes that were capable of 200X magnification

5. Beginnings of Cell Theory  1838 Mattias Schleiden stated that all plant tissues consisted of cells  1839 Theodore Schwann stated that all animal tissues consisted of cells  Each conjectured that there was a nucleus  1858 Rudolf Virchow combined the two ideas and added that all cells come from pre-existing cells, formulating the Cell Theory

6. Rudolf Virchow 1821-1902 Cell Theory “every cell originates from another existing cell like it”  All living things are composed of one or more cells  In organisms, cells are the basic units of structure and function.  All cells are produced only from existing cells.

7. Cell Theory   1. All living things are made of cells.   2. Cells are the basic units of structure and function in living things. (structure = form; function = purpose)   3. Living cells only come from other living cells.

8. Cells   1. The cell is the basic unit of life   2. Technology furthered the development of cell theory because the invention of the microscope allowed cells to be discovered.   3. The tiny structures that make up cells are called organelles which means little organs.