Warm Up
1. Describe the images below. Be descriptive in
your observations!
2. What do you think this is?
“Cells”
• Thin slice of cork described as “cells”
The Diversity of Cells
Cells
• All living things are made of tiny structures
called cells.
– the smallest unit that can perform all the
processes necessary for life
• Because of their small size, cells weren’t
discovered until microscopes were invented in
the mid-1600s.
Cell Theory Timeline
• Using pgs. 17-21, create an illustrated timeline that
includes:
– The contributions of following scientists to our knowledge
of cells:
•
•
•
•
•
Hooke
Van Leeuwenhoek
Schleiden
Schwann
Virchow
– The 3 parts of the Cell Theory
• You will then use this information to complete a
chart about the Cell Theory. This is homework if you
do not finish!
Robert Hooke
• 1665
• One of the first people to observe cells
• Observed thin slice of cork under a microscope
– Looked like tiny rooms, or “cells”
– These were dead plant cells
• Also looked at living cells
– Plants & fungi
– Both have cell walls; visible under microscope
• Could not see animal cells due to lack of cell wall
– Thought animals were not made of cells
Anton van Leeuwenhoek
• 1673
• Dutch merchant who made his own
microscope
• Looked at pond scum & saw small
“animalcules” (little animals)
– Unicellular Protists
• Also looked at blood cells, bacteria, yeast
Matthias Schleiden
• 1838
• Studied plants
• Concluded that all plants are made of cells.
Theodor Schwann
• 1839
• Concluded that all animals are also made up
of cells.
• Wrote the first two parts of the Cell Theory:
1. All organisms are made of one or more cells.
2. The cell is the basic unit of all living things.
Rudolf Virchow
• 1858
• Stated that new cells are formed only from
existing cells
• Third part of the Cell Theory:
3. All cells come from existing cells.
The Cell Theory
1. All organisms are made of one or more cells.
2. The cell is the basic unit of all living things.
3. All cells come from existing cells.
Cell Theory Chart:
Beside each part of the cell theory, write the name
of the scientist(s) whose work contributed to that
part.
Questions
• Discuss/Answer the following questions:
1. How did more than one scientist contribute to the
creation of the cell theory?
2. Why is it important that the research and experiments of
more than one person led to the development of the cell
theory?
3. Do you think that the cell theory would be as widely
accepted by other scientists if only one person had
written it? Explain your response.
4. Based on the dates from your chart, about how many
years did the development of the cell theory take?
Summary
• Video clip
• Ticket-Out-the-Door:
– 3 parts of the Cell Theory
– 2 scientists and their contributions
– 1 new thing you learned from the video clip