Note to Teachers

Evolution Academy

  

ABSTRACT

A new survey reports that high school teachers are not teaching macroevolution. To remedy this Berkman and Plutzer propose that college level teacher education include mandatory instruction in evolution. The present paper suggests that mandatory instruction, without reforming the content of that instruction, will be of little avail. A root cause is the pressure on professors at research-intensive universities to focus on the career goals of researchers, rather than of teachers. As a guide to reform, the sequence and content of a series of YouTube videos, styled after the highly successful “Khan Academy,” are outlined. These show that evolutionary principles can be expounded in everyday language without resort to complex terminology.

 

INTRODUCTION

RESEARCH_PEER_REVIEW_CONSTRAINS_TEACHING

TERMINOLOGY_BEFORE_PRINCIPLES?

WHAT_IS_TO_BE_DONE_NOW?

EVOLUTION_VIDEOS

JURASSIC_PARK

GENIC_AND_NON-GENIC_MECHANISMS

REFERENCES

End_Note_Oct_2014_Another_teacher_survey

End_Note_Dec_2014_This_piece_published_in_HSS_Newsletter

 

INTRODUCTION

There is a “pervasive reluctance of teachers to forthrightly explain evolutionary biology.” Thus conclude Berkman and Plutzer (2011) from their national survey of high school biology teachers. Among “strategies for avoiding controversy” are teaching various aspects of microevolution (e.g. molecular biology) and “completely ignoring” Darwin’s great question – the “macroevolution of species.” Their proposed solution is to focus on obtaining “better trained teachers” through “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. While an important step, the possibility that there might be problems with the instruction itself is not considered. Making more instruction available, without first checking the form and content of that instruction, makes little sense. I here suggest why college level instruction may be inadequate and, indeed, partly responsible for the mess we are in. I don’t just carp. I propose remedies. To materially support those who might choose to follow my advice, I outline the content of twelve short YouTube videos that use an approach similar to that of Salman Khan of the highly successful “Khan Academy” (Kiladze, 2010; Thompson, 2011; Wente, 2011) (see http://www.khanacademy.org).

 

RESEARCH PEER REVIEW CONSTRAINS TEACHING

As noted in the 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. This is where I believe the problem is rooted. The focus is on preparing future graduate students to contribute to 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 so as to afford little ground for suspicion that they might have not mastered a subject 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).

 

TERMINOLOGY BEFORE PRINCIPLES?

Beyond the constraints imposed by peer review lie decisions on the importance of various aspects of macroevolution and the best order in which they should be presented. Too often there is presentation of a complex pageant of life forms – wiggling nematode worms, gracefully contracting jelly fish, cuddly koalas – rather than the seeking out of key elements common to all 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. I could go 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 the nation’s high schools, the attitudes of those at the “top” trickle down to confuse and bewilder. The Khan Academy videos on biology, 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 that at lesser institutions. This finds expression in surveys such that of Berkman and Plutzer (2011). 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? An approach utilized for many decades by “Ph.D.-toting” professors such as myself, has been to speak while concurrently writing on transparent sheets displayed on a screen above the blackboard. If carried out correctly, the student feels that he/she and the instructor are sitting side-by-side, however big the class. But it is still the instructor, not the student, who determines the pace.

     Software that overcomes this problem and facilitates self-directed internet learning has been ably exploited by Khan (Kiladze, 2010). After education at research-intensive institutions (MIT and Harvard), Khan began making videos to help a relative with her maths homework. This soon blossomed into a major one-man YouTube enterprise that gained wide media attention and support from the Gates Foundation. Students see multicoloured drawings, arrows, numbers and letters, moving across a black background to Khan’s melodious vocal accompaniment. With pause and rewind options, they 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 (the French revolution), and biology. Here, presumably guided by his undergraduate lecture notes, biological terms are clearly set out. Students should do well in examinations set by busy instructors who pose questions that can be marked by graduate students or computers. Comprehension of principle often does not fall in this category.

 

EVOLUTION VIDEOS

While lacking Khan’s eloquence, in twelve short YouTube videos I have moved from overhead transparencies to a pen-tablet in order to explain evolutionary principles in everyday terms and, hopefully, with a touch of humor (Forsdyke 2011a; http://post.queensu.ca/~forsdyke/videolectures.htm). Organisms are portrayed abstractly as collections of characters. Thus the videos begin 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, so 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 slow the rate of evolutionary change. Here 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 another series of videos that may be accessed from the same web-page (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 – in form and function, and 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 would 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? There is here digression to a “thought experiment” based on Michael Crichton’s 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. It is shown that early arising mechanisms of reproductive isolation can be over-ruled (pre-empted) by later arising mechanisms. 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 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, development, and formation of gametes for the next generation. Assuming genes to have equal probabilities of mutating, it is argued that failure in the 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, in the final videos of the series, 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. Mendel is not mentioned, and Darwin and the term “natural selection” are mentioned only briefly in a late video in the series. 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 study more deeply (Forsdyke, 2001, 2011b; Cock & Forsdyke 2008). Thus, the videos should serve the various constituences in different ways. Students, at high school and above, may find them a useful supplement to their biology course materials. Instructors at various levels may find they provide a useful template regarding what is to be taught, and in what order.

     The first series of videos on evolutionary principles is followed by a second series of videos on natural selection and a third on blending inheritance - enter Darwin and Mendel. These illustrate the point that the learning of a subject and of its history should best go hand-in-hand. But that is another story.

 


REFERENCES

Berkman, M. B. & Plutzer, E. (2011). Defeating creationism in the courtroom, but not in the classroom. Science, 331, 404-405.

Cock, A. G., & Forsdyke, D. R. (2008). Treasure Your Exceptions. The Science and Life of William Bateson. New York: Springer.

Crichton, M. (1990). Jurassic Park. New York: Knopf.

Forsdyke, D. R. (2000). Tomorrow’s Cures Today? How to Reform the Health Research System. Amsterdam: Harwood Academic.

Forsdyke, D. R. (2001). The Origin of Species, Revisited. A Victorian who Anticipated Modern Developments in Darwin’s Theory. Montreal: McGill-Queen’s University Press.

Forsdyke, D. R. (2011a) Evolutionary principles in everyday language: Introduction. You Tube videos. ( http://post.queensu.ca/~forsdyke/videolectures.htm )

Forsdyke, D. R. (2011b). Evolutionary Bioinformatics. 2nd Ed. New York: Springer.

Kiladze, T. (2010). Too cool for school. Globe and Mail. Report on Business. Toronto, (December), p.10.

Gregory, T. R. (2009). Understanding natural selection; essential concepts and common misconceptions. Evolution Education & Outreach, 2, 156-175.

Thompson, C. (2011) How Khan Academy is changing the rules in education. Wired Magazine ( http://www.wired.com/magazine/2011/07/ff_khan/ ).

Wente, M. (2011) Teaching the Khan way. Globe and Mail. Toronto. 27 August.

                This page was established in July 2011 and was last edited by DRF 08 Dec 2014