Robert Hatch

SUBTOPIC:

 Darwin and Lamarck–A “Bird-Rabbit” Controversy

OBJECTIVES:

The students will:

1. debate the theories of Darwin and Lamarck
2. construct an extinct “critter,” or one on the endangered species list
3. use an imaginary organism to simulate the concept of predator vs. prey
4. determine the diet and colors of Darwin’s Finches
5. design own species of organism

Background Information

After years of studying a variety of organisms, Charles Darwin, in 1859, wrote The Origin of Species, which was a popular success. The initial printing sold out on the first day of publication, but Darwin’s theory eventually lost some of its original popularity. Although field naturalists preserved Darwin’s emphasis on the role of geographical factors on evolution, many were tempted by the theory of Lamarckism.

Jean Baptist de Lamarck was a French naturalist who published Zoological Philosophy in 1809. In his view organic beings constituted a ladder of life from simplest to complex animals, with humans at the top rung. Lamarck did little in the way of explaining the origin of this ladder, but he did offer an explanation for how organisms change over time, thus turning the ladder into what we might call an escalator of being. 

A key difference between Lamarck’s and Darwin’s ideas occurs when a variation appears. Lamarck thought that acquired characteristics arise after the environment changes. That is, a change in the environment caused a change in the organism. But Darwin believed that variations are present in a population before the environment changes. Lamarck saw evolution in terms of individuals, but Darwin realized that populations are important. 

ACTIVITY # 1:

The Great Debate: “Lamarckism vs. Darwinism”

           Two class periods, one day in the library and one day for the debate

MATERIALS:

 PERIODICALS, BIOGRAPHIES, ENCYCLOPEDIAS, PAPER, PENCIL, BOOKS, ETC. (See Bibliography)

PROCEDURE:

This exercise is intended for the combined biology and history classes. Research will be done in the media center.

1. Divide students from the two classes in teams, five per group. Each group will select a group leader and a person who will represent the group for the debate. The teacher may also ask each student to turn in a paper on his/her own individual research on the topics.
2. Students should try not to use knowledge unavailable to Lamarck or Darwin (for example, genetics).
3. Another class may be asked to serve as judges for the debate.
4. Encourage all students to be well versed on the topic they have researched.
5. As an added incentive, prizes may be awarded to the team that wins the debate.
6. Topics to be researched are:
   1. Lamarck’s law of “use and disuse” with the neo-Lamarckian theory of transmitting variability to the next generation (the inheritance of acquired characteristics)
   2. Orthogenesis (evolution in a straight line)–the tendency toward greater perfection
   3. Why Darwin’s theory of natural selection lost its popularity
   4. Explain why Lamarck’s theory of evolution is sometimes called “closed evolition” (evolutionary change predetermined) while Darwin’s is “open evolution” (evolutionary change unpredictable).

ACTIVITY #2:

A Natural Selection in “Squiggly Wormianus”

           1 class period

MATERIALS:

 CORD, PENCILS, SCISSORS, COLORED YARN (LT. BLUE, RED, PINK, YELLOW, WHITE, LT. GREEN, BEIGE, BROWN, ORANGE, DK. GREEN), METRIC RULERS.

PROCEDURE:

1. Divide the class into groups and select a site for a three meter plot in a grassy area. The plot may be staked out by using inexpensive cord and pencils for the stakes. The worms may be represented by colored yarn cut into three centimeter pieces. One member of each group may distribute the worms evenly over the plot. 
2. Groups may not watch the distribution of other team’s plots. 
3. Students may carry pieces of bark and rocks into their plot and hide the worms underneath. They may not bury them in the soil.
4. The object of this game is that each team will forage in the plots of another team and collect as many worms as possible from another team.
5. The students will assume the roles of the predatory “Wormus eatersii.” No team will hunt in their own plot, nor will any team watch the distribution of another group’s plot. 
6. Give approximately ten minutes for the predators to find the worms. When time is called, students will return to class to draw inferences on the numbers of each color wormianus that were caught, and the relationship of the other colors to the survival characteristics.

Hints: Have students cut the yarn “worms” the day before the lab activity. The groups should cut three pieces of each of the colors listed above–30 worms, 3 of each color. Choose which groups will be predators in which fields before the class activity begins.

ACTIVITY #3:

Darwin’s Galapagos Island Finches

            1 class period

MATERIALS:

 SKETCH OF THE FINCHES (NEXT PAGE), PAPER, PENCIL

PROCEDURE:

1. Divide the class into groups of three.
2. Give students a brief background on the voyage of the H.M.S. Beagle and the finches (however, do not reveal habitat, colors, or diet). Prepare a copy of the diagram below for each group of 3 students. 
3. The students will look at the pictures and guess the birds’s diet (based on the shape of their beak), their probable habitat, and their diet.
4. Students may exchange papers.
5. Allow students from each group to state their conclusions and why they made their choices.
6. After each of the 14 groups of finches have been discussed, have the students consult the article by David Lack in Scientific American, April, 1953.

ACTIVITY #4:

Design Your Own Species

            an entire class period with preparation after school

PROCEDURE:

1. Each student must develop a species that will be compatible with a particular environment. The design of the species must include all observable characteristics; i.e., an animal must have described its means of sight (be specific–such as position of eyes on head), color, texture, shape of body covering, presence or absence of tail, type of feet or hooves, means of defense, method of eating, reproductive capabilities, diet, method of hearing (include other senses if present), method of locomotion, and food gathering. A detailed description of a plant and all of its observable characteristics, i.e., type of roots, stems, leaves, flowers, method of reproduction, capability of photosynthesis, or any other food making process, could also be used.
2. A list of environmental factors must be considered so that the organism is adaptable or compatible with its environment.
3. Factors should include climate, temperature, latitude, food supply, water supply, terrestrial as opposed to aquatic, air/oxygen supply, other types of plant and animal life common to the environment, amount of duration of sunlight, presence or absence of pollution, plus various other factors students will mention as necessary for their organism to survive.

Bibliography

Bowler, Peter. Evolution: The History of an Idea. 81, 253-54.

Darwin, Charles. “The Voyage of the Beagle.” The Darwin Reader. Ed. Mark Ridley. New York: Norton, 1987. 51-52.

Eisely, Loren. Darwin’s Century: Evolution and the Men Who Discovered It. New York: Doubleday.

Farber, Paul. The Emergence of Ornithology as a Scientific Discipline: 1760-1850. Kluwer Academic, 1982.

Gould, Stephen Jay. “Darwinism Defined: The Difference Between Fact and Fancy.” Discover January, 1987.

Gould, Stephen Jay. Ever Since Darwin. New York: Norton, 1977. 81.

Mayr, Ernst. The Growth of Biological Thought: Diversity, Evolution, and Inheritance. Cambridge, MA: Harvard UP, 1982.

Mayr, Ernst and William B. Provine. The Evolutionary Synthesis: Perspectives on the Unification of Biology. Cambridge, MA: Harvard UP, 1980.

Miller, Johnathan and Boren VanLoon. Darwin for Beginners. New York: Pantheon Press.

Oram, Raymond F., Hummer, Paul J. and Robert C. Smoot. Biology, Living Systems. OH: Merrill, 1989.

Rehsberger, Boyce. “Death of the Dinosaurs–the True Story?” Science Digest May, 1989.