1. Who Discovered the Cell?

2. Prior to scientific research:
People thought disease was caused and cured by supernatural beings

3. Robert Hooke (1665)
Hooke observed a wide diversity of organisms including insects, sponges, bryozoans, diatoms, and bird feathers.
Robert Hooke coined the term “cell", in a biological context, as he described the microscopic structure of cork like a tiny, bare room or monk's cell in his landmark discovery of plant cells with cell walls.
Hooke was able to confirm Leeuwenhoek's surprising observations of bacteria and protozoans, leading to the general acceptance of the Dutch scientist's results by the established scientific community.

4. Cork Cells

5. The eyes of a fly drawn by Robert Hooke

6. Anton von Leeuwenhoek (1632-1723)
Began viewing specimens using a magnifying glass.
He then used multiple glasses to further increase the magnification.
During his lifetime he made over 247 microscopes.
After an accidental discovery of what he called “animalcules” he provided the first complete descriptions of what later came to be collectively called bacteria.

7. Light Microscope 1600’s 2 lens were combined
Over next 200 years this was improved
Up to 1500x magnification
Limited by wavelength of light

8. • Robert Brown (1831) - discovered the structure of the nucleus.
Noticed that every plant cell had an opaque spot he thought to be insignificant
He then found that every cell had this spot, even pollen and newly formed cells

9. Schleiden & Schwann (1839)
Together developed the “Cell Theory” which identified cells as the fundamental particles of plants and animals.
They recognized that some organisms are unicellular and others multicellular.
They also recognized common cell features and described them by comparison of various animals and plants.

10. Electron microscopes Developed in the 1930’s
Was able to magnify specimens 500,000x
This allowed for study of the organelles
Algae and bacteria 5,000x

15. Historical Background
• Improvement in microscopes in the last four centuries has allowed scientists to better develop the cell theory.