July 2014 – Teaching Those Who Teach Evolution: The Khan Academy Approach

Donald R Forsdyke (Queen’s University, Ontario)

Innovations in Education Series

Series Editor, Jim Evans, University of Puget Sound

Innovations in Education is a column edited by Jim Evans (University of Puget Sound). The editor warmly invites ideas and offers for future columns. Contact jcevans@pugetsound.edu.


Evolutionary concepts underlie all bioscience teaching, yet it is claimed that “our current educational system rarely, if ever, attempts to teach them in a serious and effective manner” (Klymkowsky 2011). Indeed, there is a “pervasive reluctance of teachers to forthrightly explain evolutionary biology.” So conclude Berkman and Plutzer (2011) from their national survey of US high school biology teachers. Among their “strategies for avoiding controversy” are teaching various aspects of microevolution (e.g. genetics, molecular biology) and “completely ignoring” the “macroevolution of species.” The proposed solution is to focus on obtaining “better trained teachers” by “improving the instruction they receive on evolution as undergraduates.” But this goal is to be achieved merely by making evolution a requirement for college level education courses. Although an important step, the possibility that there might be problems with the instruction itself has not been considered (Berkman and Plutzer 2012). I here suggest why college level instruction may be inadequate and, indeed, partly responsible for this “pervasive reluctance” to teach evolutionary concepts. Furthermore, I propose remedies. To support those who might choose to follow my advice, I outline below a series of free on-line videos that use an approach similar to that of Salman Khan of the highly successful “Khan Academy” (Thompson 2011; Khan 2012).

Research Peer-Review Constrains Teaching

As noted in Berkman’s and Plutzer’s survey, many high school teachers receive their undergraduate education at non-research institutions that do not offer special evolution courses. But many of the instructors at such non-research institutions have themselves been trained at research-intensive institutions. Having been engaged for several decades in research and teaching at such an institution (e.g. Forsdyke 1978), I have come to believe that this is where the problem is rooted.

The focus at research-intensive universities is on preparing future graduate students for the highly competitive “cutting edge” research carried out in laboratories such as those of their instructors. The academic goals of other students are taken less seriously. Furthermore, rather than simplify, the instructors tend to qualify and hedge, thus affording little ground for suspicion that they might not have mastered subjects that are often fraught with exceptions and apparent paradoxes. This arises, not from professorial pedantry, but from the habit of self-marketing that arises in the Darwinian struggle for career advancement known as peer review (Forsdyke 2000). Furthermore, the chances are that those who review their next grant applications will be better versed in contemporary science, than in its history. Alas, “past science is yesterday’s newspaper” (Otis 2010). So history can be safely ignored, as can the views of maverick “outsider scientists” who are unlikely to be among the reviewers (Harman and Dietrich 2013).

Hardly comparable with the careful statistics of Berkman and Plutzer (2011), these anecdotal assertions can be easy to dismiss. But their likely truth is deducible on a priori grounds by anyone who systematically reads NatureScience or The Scientist (for a recent review see Balaram 2012). It is self-evident that, for many engaged in the tooth-and-claw, winner-take-all, struggle for research funds, the placing of teaching before research is professionally hazardous. Given that some teaching must be done, it is akin to professional suicide to address the needs of future teachers rather than of those who may join one’s laboratory.

Terminology before Principles

Beyond the constraints of peer review lie decisions on the importance of various aspects of macroevolution and the best order in which they should be taught. Too often educators present a complex pageant of life forms—wiggling nematode worms, gracefully contracting jelly fish, cuddly koalas—rather than seeking out the key elements common to all of these forms. Too often Darwin’s natural selection is portrayed as fundamental, rather than as just one aspect of a much profounder whole. Too often, branching evolution precedes the relatively simpler topic of linear evolution. Too often, geographical isolation is assigned a major role to the exclusion of other forms of reproductive isolation. Too often, there is no distinction between reproductive isolation and reproductive incompatibility. Too often, there is focus on genic incompatibility to the exclusion of non-genic incompatibility. The list goes on and on.

Their heads laden with complex terminology and a wealth of technical detail, undergraduate students emerge with the idea that this knowledge is an essential prerequisite to the understanding of evolutionary principles—terminology first, principles afterwards, not the converse. Thus, from research institution to non-research institution, and on to a nation’s high schools, the attitudes of those at the “top” trickle down to confuse and bewilder. The Khan Academy bioscience videos, while excellent in many respects, tend to reinforce this.

What Is to be Done Now?

In short, I maintain that the teaching at research-intensive institutions casts a deep shadow over the education offered at other institutions. This finds expression in surveys such as that of Berkman and Plutzer (2011, 2012). Since the modus operandi of research-intensive institutions is unlikely to be remedied in the near future (Forsdyke 2000), what is to be done now about teaching evolution in high schools? Here the Khan approach, extended to teaching at college-level (Parslow 2012), may play a powerful role.

For many decades prior to the PowerPoint era, teachers spoke while concurrently writing on transparent sheets displayed on a screen. If carried out correctly, the student felt that he/she and the instructor were sitting side-by-side, however big the class. But it was still the instructor, not the student, who determined the pace. Camtasia Studio software overcomes this problem of pacing and facilitates self-directed Internet learning, a pedagogy that has now been ably exploited by Khan.

After being educated at research-intensive institutions (MIT and Harvard), Khan began making videos to help a relative with her math homework. This soon blossomed into a major one-man enterprise that gained wide media attention and support from the Gates Foundation (Khan 2012). Students see multicolored drawings, arrows, numbers and letters, moving across a black background, all accompanied by Khan’s melodious voice. With pause and rewind options, students can proceed at their own pace. Although laced with warm earnestness rather than humor, Khan’s courses have spread worldwide and volunteers have translated them into many languages. Inspired by the success of initial offerings in mathematics, physics, economics, and high finance, Khan expanded into history (e.g. the French Revolution) and the biosciences (but not into their history). Here, presumably guided by his undergraduate lecture notes, biological terms are clearly set out. Students should perform well in examinations set by busy instructors who pose questions that can be marked by graduate students or computers. Comprehension of principles often does not fall into this category.

Evolution Videos

While sadly lacking Khan’s eloquence—but one has to start somewhere—I have moved from overhead transparencies to a pen-tablet, in order to explain evolutionary principles and their historical development in everyday terms and, it is hoped, with a touch of humor (Forsdyke 2011a). Organisms are portrayed abstractly as collections of characters. Thus the first series of twelve videos begins with a vertical arrow from organisms A with a particular set of characters to organisms B where many of these characters have changed. This is linear evolution. The line is then depicted as a recurring cycle: gamete, to child, to adult, to gamete. Through ongoing variation, there is a constant pressure for branching into two independent cycles that will each tend to follow linear trajectories. However, branching is usually frustrated. Linear evolution is frustrated branching evolution.

This frustration arises in two ways. When branching lines are of different fitness, members of one line tend to degenerate, reproductively isolating them from members of the other line, which hence will interbreed only with their own kind. In this circumstance, the rate of evolutionary change is high. On the other hand, when branching lines are of equal fitness, members of the two lines are not reproductively isolated and so can interbreed. Characters may then tend to blend in children and the rate of evolutionary change is slowed. At this point the temptation to get into the intricacies of blending and non-blending inheritance is resisted. The blending idea is simple and intuitive, and amply serves our purpose. It is dealt with more fully in the later, more historical, videos (see below).

Jurassic Park

Also resisted is the temptation to move too early to branching evolution. Our vertical arrow from A to B depicts two types of temporal change: (i) in form or function, and (ii) in reproductive compatibility. When compatibility fails, new species can arise. At some point a prototypic B form (proto-B) would have become reproductively incompatible with the ancestral form A. If they could have been crossed, either no child would have been produced or, if produced, that child would have been sterile and hence unable to continue the line. A new species could have emerged. Even if not spatially separated, the reproductive isolation between A and proto-B, arising from their temporal separation, would have prevented their blending, thus facilitating progression to reproductive incompatibility. But how is this fanciful idea to be tested? How is a distant ancestor to be crossed with a much later descendent? At this point there is digression to a “thought experiment” based on the novel Jurassic Park (Crichton 1990). Here information from the DNA of extinct organisms is used to recreate the originals that are brought together in a park-like zoo where the ability to cross can be tested.

The videos then consider the segments in the unitary generational cycle where it can be interrupted to produce two separate, reproductively isolated, cycles. These have the potential to lead to organisms that have diverged both from their common ancestral form, and from each other. Yet, temporal or spatial separations may initially cause reproductive isolations, but not reproductive incompatibilities. Later these externally arising isolations may be superseded by reproductive incompatibilities arising from internal changes —some genic, some non-genic—within the organisms themselves. Prior external causes then become irrelevant. On the other hand, sometimes internally-arising reproductive incompatibilities develop first. These reproductively isolate as effectually as external separations, so that reproductive isolation and incompatibility appear together.

Genic and Non-Genic Mechanisms

Next, the videos turn to the likely number of genes corresponding to the three main segments of the unitary generational cycle. These segments are concerned, successively, with transmission of gametes, embryonic development, and formation of gametes for the next generation. Assuming genes to have equal probabilities of mutating, it is pointed out that, in general, failure in the relatively small number of genes required for gamete formation is insufficient to account for the frequency of failure of gamete formation as a mechanism for internally-arising reproductive isolation. Instead, non-genic mechanisms are invoked.

This leads to consideration of DNA, chromosomes, cell division, and the somatic cell/germ-line cell duality. Little chemical sophistication is expected. DNA is composed of four building blocks (4 colored balls) and each protein is composed of twenty building blocks (20 colored balls). When there is variation, one of these colors mutates into another. These variations may bring about both changes in characters that relate to the form or function of an organism, and changes in reproductive compatibilities.
From the above, it can be noted that terms such as zygote, base, amino acid, mitosis, meiosis, allele, clade, genome, genotype and phenotype, are avoided in the first twelve videos. Mendel is not mentioned, and Darwin and the term “natural selection” are mentioned only briefly (expanded on in later videos—see below). In a deep sense, students already know—have an intuitive understanding of—the principles of evolution. The videos try to elicit this. If the videos succeed, students should then be encouraged to master the terminology and to delve more deeply into the processes (Forsdyke 2001, 2011b).

Thus, the videos should serve the various constituencies in different ways. Students, at high school and above, may find them to be a useful supplement to their biology course materials. Instructors at various levels may find that the videos provide a useful template regarding what is to be taught, and in what order. Indeed, as with Khan’s productions, instructors may prefer to assign a video for advanced viewing, and then use class time for discussion.

History Videos

After the first series of videos on evolutionary principles, the history begins—enter Darwin, Mendel, and much more (Cock and Forsdyke 2008). The second series (twelve videos in all) is on natural selection, proceeding from Patrick Matthew in the 1830s to Samuel Butler in the 1870s. The third series (also twelve videos) is on blending inheritance with input from Francis Galton and Fleeming Jenkin. The fourth series (eighteen videos), entering the modern era, is on introns and exons. There are currently 54 videos, each around 15 minutes in length, for a total of 15 hours viewing. As back up, there are also some formal conference lectures (Forsdyke 2011c). A recurring point is that, to really understand a subject, you need to understand its history. But, paradoxically, to understand the history you need to understand the subject. So, ideally, studies of a subject and of its history should go together, hand in hand.

To understand the principles of a subject, any subject, it is often best to follow, step-by-step, how those principles first gained recognition and were reconciled with the facts of the subject, to arrive at the view we now have. In this way we can see how, although confronted with the same facts, different people weigh them differently and arrive at different interpretations, and why one interpretation is now seen as better than another. And that’s nice, because history is about people—some good, some not so good—and we all like a bit of gossip!


Teaching at research-intensive institutions casts a deep shadow over instruction at other institutions. Structural defects relating to the research/teaching dichotomy at research-intensive institutions may have impaired the education of future high school teachers. To remedy this, the Khan Academy approach has the potential to help advanced educators make the elements of their subjects match the needs of diverse audiences. This is of particular importance for the understanding of evolutionary biology.


Queen’s University hosts my evolution education web-pages, which provide access to videos on YouTube or Vimeo (http://post.queensu.ca/~forsdyke/videolectures.htm).


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About the Author

Donald R. Forsdyke is Emeritus Professor in the Department of Biomedical and Molecular Sciences at Queen’s University, Ontario. His textbook Evolutionary Bioinformatics (New York: Springer, 2011) is now in its second edition. He has made special studies of Darwin’s research associate, George John Romanes (The Origin of Species Revisited. A Victorian who Anticipated Modern Aspects of Darwin’s Theory Montreal: McGill-Queen’s University Press, 2001) and, with A. G. Cock, of William Bateson, who brought the work of Gregor Mendel to the attention of the English-speaking world (Treasure Your Exceptions. The Science and Life of William Bateson. New York: Springer, 2008).

He can be reached at the Department of Biomedical and Molecular Sciences, Queen’s University, Kingston, Ontario, Canada K7L3N6 forsdyke@queensu.ca.