Initial Planning Reflection for - An Activity Sequence on Evolution


Evolution is a series of changes, some gradual and some sporadic, that accounts for the present form and function of objects, organisms, and natural and designed systems. The general idea of evolution is that the present arises from materials and forms of the past.

Possible Related Concepts

  • Small differences between parents and offspring can accumulate (through selective breeding) in successive generations so that descendants are very different from their ancestors.
  • Individual organisms with certain traits are more likely than others to survive and have offspring.
  • Changes in environmental conditions can affect the survival of individual organisms and entire species.
  • Many thousands of layers of sedimentary rock provide evidence for the long history of the earth and for the long history of changing life forms whose remains are found in the rocks. More recently deposited rock layers are more likely to contain fossils resembling existing species.
  • Present conditions such as the salt in the oceans, continental drift, erosion of land forms, changes in organisms... can be explained as gradual and sporadic.
  • Evolution is the idea of the present arising from materials and forms of the past.
  • Sometimes a series of changes occurs so slowly or so rapidly that it is difficult to document the evolution.
  • In evolving systems, change can be gradual, steady, repetitive, irregular, or in more than one way at the same time.

What instructional theory and learning theory should be used to begin to facilitate student learning for these ideas?

I would want to begin with exploration so the students will learn through their own actions and reactions in a new situation.  If they explore new materials and new ideas with minimal guidance or expectation of specific accomplishments, the new experience should raise questions they cannot answer with their present ideas and patterns of reasoning.  Having made an effort that most likely will not be completely successful, they should be motivated to ask questions and begin to look for ideas that will lead them to self-regulation. Meanwhile, I will have collected enough assessment data to begin to know what they understand and where I might begin to facilitate their learning in the second phase: invention.

What activities could be used for the first activity with students?

Activities Review a resource file or a list of possible activities that would fit the concepts and generalization.

List of possible activities

1.  Showing a video that traces the evolution of the horse and elephant by reviewing fossil evidence, procedures of dating rock strata, and reconstructions of ancient forms of these organisms?

2.  Arranging for a trip to a museum where students are free to select exhibits that enable them to observe fossils of ancient organisms, follow the geologic history of the earth, look for relationships between climate changes and changes in populations or organisms, and trace the evolutionary lines of the horse, Darwin’s finches, or the skeleton of vertebrates?

3.  Providing groups of students with chalk, meter sticks, and a list of important events in geologic and archeologic time, as a challenge to construct a time line indicating the relative occurrence of these events on a time line?

4.  Providing an explanation of how biotic potential, limiting factors, variation, heredity, and natural selection interact over enormous spans of time to result in the changes in organisms?

5.  Providing a laboratory where students observe, draw, and classify with the aid of a key- a variety of simulated fossil specimens in a kit from the science supply center?

6.  Presenting an explanation concerning the five basic processes recognized in evolution (gene mutation, changes in chromosome number and structure, genetic recombination, natural selection, and reproductive isolation) and diagramming how these interact to result in change?

Making a decision

Review what resources are needed for each activity and the preparation of students needed for each activity. Eliminate activities that wouldn't fit the availability of resources and the readiness of students. Then think about how each would or would not be good to use as the first activity.choice.  When you have done that, compare the ideas below with yours, and if possible, with those of others.

1.  Videos are popular ways of introducing new topics.  In this case the film presents observations the students might make in a museum or laboratory if they have access.  However, I would recommend the video be used later as review or parts shown, then pause or stop to provide time to think and talk, then continue for a short period, pause or stop again to talk, and so forth in this manner through the video (maybe skipping around if necessary).  Films raise questions, provoke inquiry, or present contradictions less effectively than first hand experiences.  Since paying attention to the video discourages or postpones deep thinking, few students watching a video for the first time think critically about what they observe.  Furthermore, seeing a picture of an object or process does not carry the impact of seeing the object or influencing the process oneself.

2.  This approach is very worthwhile as an introductory activity to a difficult topic.  Students have a great deal of freedom to examine and compare past life forms according to their own interests and curiosity.  Their experience and discussions with one another will lead them to ask themselves how old life forms disappeared from the face of the earth as newer ones evolved.  Seeking answers to this question is the aim of evolution.

3.  This activity can be very effective for getting students to appreciate the tremendous span of time during which evolution operated.  As described, it is open and allows students initiative, freedom to make mistakes, and opportunities for self-regulation as they discover misconceptions between their preconceived ideas and the lengths of time-line segments.  Because of the narrower focus of this activity, it is NOT as good an introduction to the entire section as alternative two.

4.  This theoretical approach would be inappropriate as an introduction of a new topic because it takes for granted that all students have a good grasp of the five rather difficult concepts.

5.  Using a key for classifying objects can be worthwhile for elementary school pupils in that it involves class inclusion, a reasoning pattern many children of this age find challenging.  Very few older students would be challenged by this activity, and most would not re-examine their reasoning patterns.

6.  This approach, often in the form of teacher talk, provides a unified picture and appears efficient, it is too abstract for most student s and does not provide them with any way by which they can judge the validity of a statement for themselves.

Reflect on the positives and negatives for each and make a decision as to what you believe might be the best before continuing.

  The recommended approach is number two is an example of an exploratory activity upon which later conceptual understandings can be built.  It represents the exploration phase of a learning cycle based on current theories of learning and is designed to encourage self-regulation.  The three phases of the learning cycle are exploration, concept invention, and expansion (Sunal & Sunal).


Dr. Robert Sweetland's Notes ©