The document provides instructions for students to create a timeline on the development of the Cell Theory beginning with the invention of the compound microscope. It lists 7 scientists who contributed to cell theory - Robert Hooke, Anton van Leeuwenhoek, Matthias Schleiden, Theodor Schwann, Rudolf Virchow, Louis Pasteur, and Zacharias Jansen. For each scientist, students are to include how they contributed to cell theory, when they made their contribution, and how their work helped reject the theory of spontaneous generation. A rubric is also provided to evaluate the timelines.

1. TEKS 7.12F: Recognize that according to cell theory all organisms are composed of cells and cells carry
on similar functions such as extracting energy from food to sustain life.
Purpose: To learn about the scientists who contributed to the development of the
Cell Theory and to the rejection of spontaneous generation.
TASK: You will use internet resources to create a timeline that begins with the
invention of the compound microscope to the experiment that finally dispelled the
outdated idea of spontaneous generation. After completing your timeline, you should
summarize the three parts of the cell theory in your own words.
The Scientists
(Include pictures in your timeline)
1) Zacharias Jansen 2) Anton van Leeuwenhoek
3) Robert Hooke 4) Matthias Schleiden

2. 5) Theodor Schwann 6) Rudolf Virchow
7) Louis Pasteur
Research the following questions about each scientist and include this
information in your timeline.
* How did this scientist contribute to the cell theory? (Make sure the information
that you provide here is related to the cell theory.)
* When did this scientist make his contribution to the cell theory?
* How did this scientist's invention, idea, or experiment help lead to the rejection
of spontaneous generation?

3. Descriptions of Scientists
Robert Hooke 1965 Anton von Leeuwenhoek Theodore Schwann
All living creatures are made up of 1674 German physiologist, generally
cells. Discovered this when Van Leeuwenhoek is credited considered the founder of
looking at some cork bark under a with having invented the modern histology, the study of
microscope in the 17th century. the structure of plant and
microscope and saw what looked
He was able to see animal tissues.
like a series of tiny rooms, or
cells. microscopic organisms and
drew them.
Matthias Schleiden 1838 Rudolf Virchow Zacharias Jansen
a German botanist, concluded All life on the planet is made up of Zacharias Janssen is
that all plant tissues are cells. This theory was the generally believed to be the
composed of cells and that an backbone for the cell theory we
embryonic plant arose from a first investigator to invent the
know today compound microscope.
single cell.
Louis Pasteur
spontaneous generation of
microscopic animals.Pasteur boiled
some broth to kill any microbes
present. With special glassware, he
allowed air to circulate over the broth,
but prevented microbes in the air
from reaching the broth. As Pasteur
expected, no microbes appeared in
the broth. Pasteur’s findings showed
that microbes were not spontaneously
generated from the broth itself.

4. Sample Rubric
Beginning Developing Accomplished Exemplary Score
1 2 3 4
Accuracy Information Information Information Information
shows no contains contains minor is accurate
research on multiple inaccuracies and
the part of inaccuracies and/or is missing complete. It
the student and/or is some is written in
and/or many missing a information, a clear and
items are substantial and/or is concise
incomplete amount of somewhat wordy fashion.
and/or information or unclear.
information and/or is very
was copied wordy.
and pasted
from
sources.
Creativity Creativity is Some effort Assignment is Assignment
completely to be creative. colorful and is original,
lacking. No Color and includes images colorful, and
color or images may yet it is lacking includes
images not be innovation. images.
used. relevant to Student went
assignment. above and
beyond the
parameters
of the
assignment.

5. Grammar There is no Multiple Few No
evidence of grammatical grammatical grammatical
appropriate errors are errors are errors are
grammar in present but detected. detected
the text still
assignment. shows some
effort on the
part of the
student.