||Lesson Plan: The Cell - A Historical Perspective
This lesson focuses on the historical component of cell biology. Students learn about the invention of the microscope and the impact that this invention had on scientific discovery. Students also learn about the concept of spontaneous generation and how this concept, once defended and supported by scientists, was rejected because of the scientific process. Finally, students become familiar with the cell theory. Aside from understanding the actual components of the theory itself, students should see that scientific theories are not generated overnight, but require thorough testing, research, and review. Theories are also based upon a body of knowledge that has been compiled by many individuals, not just the work of one.
Three questions that should be emphasized during the course of this lesson are:
1) How would our lives be different if we had never realized the existance of microorganisms?
2) The microscope and numerous experiments lead to the rejection of spontaneous generation. This idea had been accepted by most people, including scientists, for over 200 years. How does this demonstrate the true nature of science?
3) Examine the timeline. How long did it take to develop the cell theory? What does this imply about the formulation of a theory?
MOTIVATION / INTRODUCTION
The concept of spontaneous generation can be presented in a few different ways by using the following website:
1) Read the observations to the students. Have them think about what people may have concluded from these observations. Discuss these ideas as a group. Introduce the term "spontaneous generation." Ask students how they think this idea may have ultimately been rejected. Use this as a segue to the webquest.
2) Print out the page from the web link above. Paste each observation onto separate index cards. Do not include the conclusion. Provide an index card to a group of students (2-4). Have them read and discuss the observations. After all groups have completed this, discuss their conclusions. Did groups with the same card come up with similar conclusions? Why or why not? Discuss these ideas as a group. Introduce the term "spontaneous generation." Ask students how they think this idea may have ultimately been rejected. Use this as a segue to the webquest.
The Cell: A Historical Perspective
This webquest focuses on the content of this lesson while at the same time providing them an opportunity to use the Internet for research. They also gain practice using Inspiration in order to create a timeline.
After students have completed the webquest, they may complete the conclusions section as an additional classwork assignment, a homework assignment, or alternatively the questions can be used for class discussion.
1) The webquest includes a grading rubric.
2) The conclusion questions following the webquest require higher order thinking skills.
3) A teacher or text-based quiz or test may follow this lesson.
1) Reading and writing: Students will stumble upon other scientists during their webquest that are not part of the timeline. Have them write a paragraph about a scientist of their choice who was not included on the timeline.
2) Reading and writing: Students write a newspaper article declaring that spontaneous generation has been rejected. They include "interviews" with scientists from their timeline and discuss how this may impact human history.
3) Demonstration or hands-on: Replicate Pasteur's experiment. The procedure is outlined in the spontaneous generation website. Before conducting the experiment, have students make predictions about the results. This is a good opportunity to reinforce the scientific method.
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