Day 12 and 13: Theories: HOW DO SCIENTISTS THE BEST ONE?

This lesson is based on the Mini-Lesson: Lamarck vs Darwin: Dueling Theories, by Richard Firenze. Available on line at

Reflective Introduction: This lesson will focus more on critical thinking, forming testable hypotheses. Students will compare the five models that explain the diversity of life found on this planet.

Global Objectives/ Related topics: This lesson will reinforce the following concepts already covered in this unit:

1. Evolution proceeds by the process of variation, a genetically random process, and selection, an environmentally driven non-random process.

2. Organisms do not get what they "need" through "inner wants" or through "use and disuse' "Individual intentions do not play a role.

3. Acquired characteristics are not passed on to offspring,

4. Mutations are not directed for the benefit of the individual.

5. Evolution is neither random nor teleological. It is, in fact, driven by both historical contingencies and the non-random, yet non-directed, process of selection.

Primary Objectives:

1. Students will be able to list the evidence for a given "theory".

2. Students will be able to compare "theories" on the basis of this evidence.

3. Students will be able to suggest other criteria which could be used to choose best "theory".

4. Students will be able to state how this investigation relates to the fluid nature of science.

Materials:

Student handouts:

  • Set of 5 theories: scenarios for the origin of diverse life, enough so that each student gets one theory to analyze.
  • Worksheets with tasks and questions for individual evaluation of a “theory”
  • Worksheet with tasks and questions for group comparison of the 5 theories

Procedure:

DO NOT TELL THE STUDENTS WHOSE THEORY THEY HAVE UNTIL AFTER THE DISCUSSION.

Day I / 1. (15 minutes) Open with a min-lecture on the definition of theory and hypotheses. Review that theory is a term reserved for scientific ideas and not religious beliefs and the a hypothesis may become a theory. Compile a definition of each from students and then clarify them. / START
Day I / 2. (5 minutes) Distribute the “theories” so that each student has one. Now pass out the other student handouts and explain the assignment.
Day I / 3. (30 min) Allow the rest of class for each student to finish the “Individual Theory Evaluation”. If they do not finish they have homework. / MIDDLE
Day I / 4. Tell students that if they have not finished they must do so for homework. Collect all they have been completed and pass out the next day. / END
Day II / 1. Pass back any papers collected the day before. They brake the class up into groups of 5, so that all 5 Theories” are represented in each group. Those who were absent the day before or who did not do the work can be apportioned to different groups to sit in on the group discussion. If there are a few “extra” students who did evaluations put them into the other groups and allow for duplicates. Try to balance the teams so that all have 5-6 students. / START
Day II / 2. Each group must complete a “Group Theory Evaluation” form, using discussion and consensus. Teacher can provide the “age” of each “theory” when asked by a team (see question #3 on ws). / MIDDLE
Day II / 3. Finally, have each group report out to the class different aspects of their group evaluation. Teacher should make sure that the concepts, as listed above are accurately and clearly addressed during the discussion. / END
Day II / Finally lead a class discussion in which they classify each “theory” as scientific or non-scientific. Have them use the same criteria they used in the NATURE OF SCIENCE lesson. Give them the name of the theory and then explain the HW. / END

HW:

Have each student write a paragraph explaining why scientists feel the Darwin’s theory is the best theory. If they disagree allow them to write a seconed paragraph explaing why. Note: Disagreements will not be counted as wrong, all are entitled to their opinions and the opinion of scientists is not necessarily the correct one, but they must understand the scientist theory and position even if they do not agree.

Teachers Notes:

The theories used are:

Theory A: Aristotle, circa 350 BC

Theory B: Jean Lamarck, 1809

Theory C: Empedocles et al, circa 500 BC

Theory D: Charles Darwin, in his Origin of the Species, 1859

Theory E: “Scientific Creationism” a la Morris and the Institute for Creation Research, circa 1960.

Adjustments for special needs students:

Though there may be need for production audio tapes of material or larger type additions of material this lessons should be something all students can accomplish. Thus, one should refer to the students IEPs to be sure, however, little accommodations will likely be necessary.

Evaluation and assessment

The students' Individual worksheets” and homework can be collected, corrected and evaluated. They will count as a homework grades. The group presentations will be a good evaluation tool for deciding the level of student understanding.

Safety

N/A

THEORY A

Life has always existed.

The life forms presently on the planet are the ones that have always existed.

There is an immutability to life (life does not change).

All biological types remain the same through time.

Man is at the apex of this static ladder of nature.

There is a fixed hierarchical order to life.

There is a “Great Chain of Being” that extends unchanged and unbroken from the beginning of time to now.

Some lower life forms may spontaneously arise, if proper conditions exist.

No life forms have ever become extinct.

Fossils are merely chance aberrations in rocks.

Nature is simply the monotonous and eternal recurrence of the same things.

THEORY B

Life originated as an act of divine intervention.

Life forms continue to arise by spontaneous generation.

There is a “Vital Force” that drives the formation of life.

Within each living group, there is an inherent perfecting power.

In the animal group, this perfecting power slowly and continuously directs the evolution of the group towards the human type.

Man evolved from an orangutan-like hominoid somewhere in the vastness of Asia.

Species are not fixed, but are changeable.

Species change in slow, gradual steps, never in sudden leaps.

There are two basic laws which govern these changes:

1. In every animal which has not passed the limit of its development, a more frequent and

continuous use of any organ gradually strengthens, develops, and enlarges that organ,

and gives it a power proportional to the time it has been so used; while the permanent

disuse of any organ imperceptibly weakens and deteriorates it, and progressively

diminishes its functional capacity, until it finally disappears.

2. All the acquisitions or losses wrought by nature on individuals, through the influence of the environment in which their race has long been placed, and hence through the influence of the predominant use or the permanent disuse or any organ, all these are preserved by reproduction to the new individuals which arise, provided that the acquired

modifications are common to both sexes, or at least to the individuals which produce

young.

Evolution, therefore, is the gradual change of species as a result of accumulated acquired modifications.

THEORY C

Water is the basic stuff of the cosmos.

Life first appeared in water.

A primordial slime formed in the waters of the Earth.

The primitive oceans of the Earth were filled with preformed, free-floating organs.

These organs came together haphazardly, by chance, to form organisms.

Most of the resulting organisms were monstrosities and perished in the struggle for existence.

Some of the organisms were successful in survival and reproduction, giving rise to the

organisms presently here.

Fossils are proof of the monstrosities which failed to survive.

Life forms first developed in water and then moved onto the land.

Plants formed first, then animals.

The line leading to man moved through a fish-like stage.

THEORY D

The origin of life is unknown, but life is certainly very old.

At its core, there is a basic sameness to all life.

All organisms tend to increase their population numbers at a geometric rate.

Over many generations, however, the number of individuals in a species tends to remain constant.

There must, therefore, be a struggle for survival in which some individuals die or in other ways are prevented from reaching their full reproductive potential.

Variations (some of which may be inherited) are found among the individuals in each species.

Some variations are favorable to an organism and help it to survive and reproduce abundantly.

Surviving organisms pass their hereditary variations to their offspring.

In time, great differences arise, until a new species evolves from an old species.

Evolution is, therefore, the change of species as a result of the natural selection of favorable variations in inherited characteristics.

THEORY E

Physical events can have non-physical causes.

Life on this planet resulted from a single act of creation by a divine being.

Each of the major kinds of plants and animals was created functionally complete from the beginning, and did not evolve from some other kind of organism.

Changes in basic kinds since their creation are limited to “horizontal” changes (variations) within the kinds, or “downward” changes (e.g., harmful mutations, extinction).

The processes used by the Creator are no longer operating anywhere in the universe.

Processes today operate primarily within fixed natural laws; however, there is always the possibility of miraculous intervention in these processes by their Creator.

There is strong scientific evidence to indicate that most of the earth’s fossil-bearing sediments were formed in a recent global hydraulic cataclysm.

The Bible is infallible and completely authoritative on all matters with which it deals; it is free from error of any sort, scientific and historical as well as moral and theological.

Name______Date______

Class______Period______

INDIVIDUAL THEORY EVALUATION FORM

Theory being evaluated______

1. Write one complete sentence identifying the problem/question this theory is attempting to explain.

2. Do the elements of this theory seem to fit together well? Are there any elements in the theory that do not seem to agree with other elements? List any such internal inconsistencies you can find.

3. Are there elements in the theory that are untestable? In other words, are there elements for which you can not think of a way to design an experiment that would produce data to support or refute the element in question? List any such elements and tell why you think they are untestable. If there is a large number of these elements, limit your answer to the two you think are most important.

4. Are there any elements in the theory that seem to be in disagreement with currently accepted “facts”? List any such elements and briefly say what “fact” each disagrees with.

5. List the one or two elements of the theory that seem to make the most sense to you. Tell why they seem to be so sensible.

6. Do you think this theory could be correct? Give the major reasons for your answer.

Names ______Date______

______Class______

______Period______

______

______

GROUP THEORY EVALUATION FORM

1. Each member of the group will explain his/her assigned theory to the other members of the group. Make sure each member of the group understands each of the theories.

2. Give the major strengths and weaknesses of each theory, as discussed by the team. If the tables below are not large enough, copy their layouts on separate sheets of paper.

THEORY A

Strengths Weaknesses

THEORY B

Strengths Weaknesses

THEORY C

Strengths Weaknesses

THEORY D

Strengths Weaknesses

THEORY E

Strengths Weaknesses

3. Rank-order the theories form “most likely to be correct” to “least likely to be correct”, according to group consensus.

Most likely to be correct: ______

______

______

______

Least likely to be true: ______

4. Arrange the theories in correct chronological sequences, from the most recent to most ancient:

Most likely to be correct: ______

______

______

______

Least likely to be true: ______