1. The Cell Theory Microscopes Provide the Windows to the World of the Cell

2. Anton Van Leeuwenhoek (1600’s) Credit for the first microscope Looked at pond water and saw “wee beasties”

3. Robert Hooke Observed plant stems, wood, and cork (1600’s) He used a compound scope (series of lenses) He was the first to use the term “cell” What cell part did Hooke observe? Cell Wall

4. Robert Brown (1833) Observed that cells had a dark structure within plant cells Brown observed the nucleus

5. Matthias Schleiden (1838) Stated that all plants are made of Cells Made many observations of plants around the area

6. Theodor Schwann (1839) Stated that all animals are made of Cells Observed many animal tissues

7. Rudolf Virchow (1855) Stated that all cells come from pre-existing cells Cells arise from the division of pre-existing cells

8. Louis Pasteur (1859) Disproved the Theory of Spontaneous Generation

9. Cell Theory Cell Theory is the unifying theme in biology because it emphasizes the similarity of all living things All organisms are composed of one or more cells. Cells are the smallest living units of all living organisms. Cells arise only by division of a previously existing cell.

10. Exceptions to the Cell Theory Viruses – are not cellular Mitochondria and chloroplast – each contain genetic material and can reproduce