Robert Hatch

SUBTOPIC:

 The Voyage of the Beagle and Darwin’s Observations

OBJECTIVES:

The students will:

1. become familiar with the main events of Darwin’s voyage
2. understand the importance of geographic distribution and geographic isolation on the formation of a new species
3. understand how living things can change over a period of time and how these changes can increase the chances of their survival

Background Information

Charles Darwin spent many years studying various living organisms and in 1859 wrote a book explaining how he thought these organisms changed over a period of time. His theory can be summarized in three main points: 1) living organisms over-reproduce, resulting in a struggle to survive 2) variation exists in offspring and 3) the survivors are the organisms most well adapted to the existing environment.

Darwin spent five years on the H.M.S. Beagle traveling around the world. The notes taken on this voyage were crucial in his development of the theory of natural selection. From his travels on the Beagle, Darwin was aware of the difference in species at various geographical locations. He believed strongly that the environment was involved in the extinction of certain species and the birth of others. His viewpoint was that certain individuals of species changed over time in a manner which caused them to become different enough from other members of the species to constitute a new species. He realized that this happened over a long period of time and that the process was unpredictable.

ACTIVITY #1:

The Five Year Voyage

           1 class period

MATERIALS:

 MAPS (SEE ATTACHMENT A)

PROCEDURE:

Instruct students to plot the coordinates of Darwin’s trip around the world on the Beagle. Dates and places have been included.

ACTIVITY #2:

An Evolutionary Riddle

           1 class period

MATERIALS:

 ATTACHMENT B

PROCEDURE:

1. Explain to students that in this activity they may ask questions that can be answered only by a “yes” or “no” in attempting to find out more about the situation described below.
2. Present the following information to the students about the CASE by writing it on the board before class:
   In a densely wooded suburb of England, certain dead bodies are accumulating in increasingly large numbers. Those that survive do so mostly because of the nearby factory. Why?
3. Allow the students to uncover as much information as they can; e.g., let them discover that the bodies were moths and that the differences between those that tended to perish versus those that tended to survive was color.
4. After students have exhausted a supply of questions (answered only with “yes” or “no”), they will put together the pieces that finally lead them to a plausible hypothesis.
5. Present the following information to the students about the EXPLANATION:
   Before the Industrial Revolution, the trees near Manchester were a light grayish color, due to the lichens growing on tree trunks. Peppered moths that lived in the area were also a light color. Their light color served as a camouflaging technique, hiding them from the birds who preyed upon them. As the Industrial Revolution unfolded, the trees became darker due to the factories’ soot. In 1848, the first dark colored peppered moths began to appear. Today, 90% of the population in this area are dark in color.
6. Next, they can complete the exercise in the attachment B.

ACTIVITY #3:

Darwin Today: Distance and Density is Relative!

            1-2 Periods

Additional background information for activity

It took Darwin a little over three years to reach the Galapagos Islands–a place where a variety of living organisms where observed. Darwin made many references to variations in the appearances of finches on this island, and he is famous for the theory derived from this study. Now, a century after Darwin’s death, we must begin to manage another Galapagos species–humans.

MATERIALS:

 Attachments C and D

PROCEDURE:

1. Using the mapping exercise as a reference the student can calculate the time it took Darwin to reach these islands. (Attachment C)
2. Next, the students can compare the calculation to the amount of time it takes us to reach the same location today. (Attachment D)
3. Once the easy accessibility has been made clear, students can begin to speculate about possible impacts made on this society by humans (refer to January 1988 article in National Geographic).
4. Use the “webbing” technique to correlate the main idea of the article (the center circle on the board) with all relevant supportive branches of thought (connected to the main thought/circle).
5. The next step is to begin hypothesizing, analyzing and evaluating these ideas so that a general conclusion can be drawn.
6. To complete this activity, walk students through a graphic representation of increasing population density. One way to do this is to ask all students to stand by their desks. Then reduce the size of the room by half and ask all students to get into the “half.” Continue to do this until the space between the students creates a degree of “uncomfortability.” This can then be tied to what is happening in the Galapagos and what new changes might be expected.

ACTIVITY #4:

“Win, Lose or Draw”

            1 class period

PROCEDURE:

1. Separate the class into groups of any size.
2. Instruct students to write detailed summaries of Darwin’s adventures and subsequent theories, including the problems he encountered and his reluctance to publish his work.
3. Combine and edit these summaries to form one complete summary, then duplicate and distribute to students.
4. Using the terms and instructions given below, play the game “Win, Lose or Draw” with the students.
   “Win, Lose, or Draw,” the popular television game show, can be modified and played in the classroom. Also known as “Pictionary,” it is played as follows:

   1. write terms on separate cards
   2. divide class into teams
   3. a member from the starting team picks a card and attempts to draw the term on the board, using no symbols of any kind
   4. the drawer’s team members try guess the term
   5. usually a time limit is enforced, and if the term has not been guessed by that limit, no points are awarded 6) if the correct answer is given, however, one point is awarded to the team.

TERMS: BEAGLE, GEOGRAPHIC ISOLATION, ADAPTATION, NATURAL SELECTION, GALAPAGOS ISLANDS, DARWIN’S FINCHES, VARIATION, STRUGGLE FOR EXISTENCE, ACQUIRED CHARACTERISTICS, POPULATION DENSITY, EVOLUTION

Bibliography

A World View. Silver Burdett Company. 436.

Bowler, Peter. Charles Darwin. Blackwell.

Darwin, Charles. Origin of Species.

Darwin, Charles. “The Voyage of the Beagle.” Darwin Reader. Ed. Mark Ridley. Chapters 3-5.

DeBeer, Gavin. Charles Darwin Evolution By Natural Selection. Doubleday. 39.

Greene, John. The Death of Adam. Iowa State UP.

Miller, Johnathon and Vanloon Boren. Darwin for Beginners. New York: Pantheon Press.

National Geographic. January 1988. 128.