Molecular Evolution Lessons

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Molecular Clues to Evolution

Be sure to read the excellent article about the many molecular clues to evolution by Thomas G. Gregg, Gary R. Janssen, and J.K. Bhattacharjee: "A Teaching Guide to Evolution" in the NSTA journal The Science Teacher of November, 2003, pp. 24-31. A PDF copy is available here for your convenience, reproduced with permission from The Science Teacher, a journal for high school science educators published by the National Science Teachers Association (, and the kind consent of the authors.

This article provides a very clear summary explanation for several of the many clues from molecular biology, including the following (with links to ENSI lessons that present those topics):
1. The Universality of DNA structure and function - and its code.

2. Patterns of Similarities among diverse organisms pointing clearly to distinct groupings, using "comparative genomics" studies; this has given us the three domains of life - and how they are related; "From comparative genomics we have discovered that making new genes by exon shuffling is a very important source of genetic variation, beyond mutation and recombination, upon which natural selection can act." Nice diagram of the 5 domains on page 25 of article.

3. Using Non-functional Sequences of DNA, e.g., pseudogenes, LINEs, and SINEs; studies of these have revealed the close relationship of whales to artiodactyls - especially hippos. Our Pseudogene Suite (3 lessons: A,B,C): Vitamin C and Common Ancestry, and the Whale Ankles and DNA lesson get into these issues.

4. Metabolic Pathways: the kind of evidence that shows how complex processes, like the blood clotting cascade, very likely evolved, and wouldn't need to require any kind of "intelligent design" as some have proposed. We are looking for any kind of interactive lesson that effectively explores the evolution of metabolic pathways - let us know if you have one.

5. Genetic Variability of Proteins: Cytochrome c and Hemoglobin sequences are compared in humans and chimps - for which we have two lessons that you could use: Molecular Sequences & Primate Evolution (beta Hemoglobin), and Molecular Biology & Phylogeny (cytochrome c).

6. Population Genetics and how this field informs evolutionary studies.

7. Gene & Genome Duplication

Teaching Evolution Directly: "In this summary we have emphasized relatedness among very different kinds of organisms rather than the fact that species change. Most creationists now concede that species change, even to the extent of giving rise to new species. However, creationists continue to insist that these changes are "microevolutionary," leading only to modifications within a "kind" [sic] and to nothing fundamentally new. All of the molecular evidence to date indicates that presently existing organisms are related and so must necessarily have arisen from a common ancestor through a process of evolution."

Click here for our list of Molecular Evolution Lessons


"The Nature of Science and Perceptual Frameworks" by Michaels and Bell (pp. 36-36). This article artfully uses optical illusions to engagingly illustrate many of the popular misconceptions about human aspects of doing science - revealing important issues of this "Nature of Science." To the historical examples of the subjectivity of science given in the article - and how creative changes in framing and perspective led to new and more accurate understandings - I would add the longstanding assumption by early naturalists that species were created and fixed - never able to change into new species. See our many suggestions for using illusions to teach the nature of science.

"Evolution and Intelligent Design" by J. Staver (pp. 32-35), plus the Commmentary "The Risk of Intelligent Design" by L. Sharmann (p. 12). Very useful insights to understanding and dealing with these topics in the classroom. For some additional articles and discussions of ID, click HERE, and select "Evolution vs Ceation Issues."

"Why Aren't There More 'Intermediate' Forms Found Between Species?" in the "Ask the Expert" column on page 74. Useful examples, including the sequnce of early whale fossils (see our popular "Becoming Whales" lesson for teaching this example). Note that this issue pre-dated the discovery of Tiktaalik, the "fish with neck and wrists" discovered in 2004 by Neil Shubin and colleagues - a great example of a startling discovery that filled a "problem gap" in the eyes of evolution critics, and also demonstrated how theories can lead to productive predictions (existing transitional fish - to - tetrapod fossils indicated a 375 mya time period for when the transition took place. They looked in exposed sediments of that age, and found the fossils). See Your Inner Fish link for PowerPoint slides to help teach this. If you develop a useful lesson around this discovery and its implications, please share with the ENSI site.