1. The Cell Theory

2. What is a cell
The cell is the basic structural and functional unit of life.
The average human being is composed of around 100 Trillion individual cells!!!
It would take as many as 50 cells to cover the area of a dot on the letter “i”

3. Discovery of Cells
1665- English Scientist, Robert Hooke, discovered cells while looking at a thin slice of cork.
He described the cells as tiny boxes or a honeycomb
He thought that cells only existed in plants and fungi

4. Anton van Leuwenhoek
1673- Used a handmade microscope to observe pond scum & discovered single-celled organisms
He called them “animalcules”
He also observed blood cells from fish, birds, frogs, dogs, and humans
Therefore, it was known that cells are found in animals as well as plants

5. What is the Cell Theory & How was it developed??
In your Journal: In one or two complete sentences describe what the following quote tells us about the origin of new life.
Quote:
“Fireflies rise from the morning dew, fish and frogs from a muddy stew, maggot worms from rotting meat and mice shall come from sweat and wheat.”

6. Year Gap???
Between the Hooke/Leuwenhoek discoveries and the mid 19th century, very little cell advancements were made.
This is probably due to the widely accepted, traditional belief in Spontaneous Generation.
Examples:
-Mice from dirty clothes/corn husks
-Maggots from rotting meat

7. What is Spontaneous Generation?
the belief that living things can come from non-living things.
Was once thought to be true, but is now known to be false!
How was it disproved?
- the following scientists with their combined experiments proved the theory of spontaneous generation to be false & helped develop the Cell Theory.

8. Who was… Francesco Redi? (1668)
scientist whose experiments proved maggots did not come from rotting meat.

9. 19th Century Advancement
Much doubt existed around Spontaneous Generation thanks to Reddi’s experiments
Conclusively disproved by Louis Pasteur ? = +

10. Who was…Matthias Schleiden? (1830’s)
Onion cells Elodea cells Cork cells
studied numerous plant parts under the microscope and declared “ALL PLANTS ARE MADE OF CELLS!”

11. Who came up with this theory?
All plants are made of cells!
1. Schleiden (circa 1838)
Onion skin cells

12. Who was… Theodor Scwhann? (mid 1830’s)
Cheek cells Amphibian Blood
Used a microscope to observe numerous animal tissues and declared “ALL ANIMALS ARE MADE OF CELLS!”

13. Development of Cell Theory
1838- German Botanist, Matthias Schleiden, concluded that all plant parts are made of cells
1839- German physiologist, Theodor Schwann, who was a close friend of Schleiden, stated that all animal tissues are composed of cells.

14. Who was… Rudolf Virchow?
- observed living cells dividing and declared “ALL CELLS COME FROM OTHER LIVING CELLS!”

15. Development of Cell Theory
1858- Rudolf Virchow, German physician, after extensive study of cellular pathology, concluded that cells must arise from preexisting cells.

16. The Cell Theory Complete
The 3 Basic Components of the Cell Theory were now complete:
1. All organisms are composed of one or more cells. (Schleiden & Schwann)( )
2. The cell is the basic unit of life in all living things. (Schleiden & Schwann)( )
3. All cells are produced by the division of preexisting cells. (Virchow)(1858)

17. Modern Cell Theory
Modern Cell Theory contains 4 statements, in addition to the original Cell Theory:
The cell contains hereditary information(DNA) which is passed on from cell to cell during cell division.
All cells are basically the same in chemical composition and metabolic activities.
All basic chemical & physiological functions are carried out inside the cells.(movement, digestion,etc)
Cell activity depends on the activities of sub-cellular structures within the cell(organelles, nucleus, plasma membrane)

18. How Has The Cell Theory Been Used?
The basic discovered truths about cells, listed in the Cell Theory, are the basis for things such as:
Disease/Health/Medical Research and Cures(AIDS, Cancer, Vaccines, Cloning, Stem Cell Research, etc.)

19. Cell Theory Timeline Project
Materials: book, butcher paper, markers 
Purpose: To understand what a theory is, how the cell theory developed and how this development follows the pattern of scientific development.
Background: Science distinguishes itself from other ways of knowing and from other bodies of knowledge through the use of empirical standards, logical arguments, and skepticism, as science strives for explanations of the world. Scientists develop theories to explain a large range of observations. Theories are tested by many independent scientists an allow a scientist to make accurate predictions about new situations. The Cell theory has been developed over time and new knowledge has often been based on technological breakthroughs.  
Procedure: Using Butcher paper create a timeline which follows the development of the cell theory. For each major development list the date, name of scientists involved and how one or more of the following influenced it’s acceptance. Include Pictures and descriptions
1. Science uses experimentation and observation to understand the natural world
2. Science is reproducible, because nature usually behaves in a predictable manner
3. As technology advances scientists are able to obtain new, and more accurate evidence