BI302 Evolution: half-credit course, winter semester.
Hours of instruction: 3 lecture hours plus 1.5 tutorial/seminar hour per week.
Prerequisite: BI224 Genetic Analysis.
Evolution comprises two separate but related processes within biology: the change of frequency of heritable traits within populations over time (adaptation), and the historical pathways that relate all living and extinct organisms (phylogeny). This course focusses primarily on the first of these processes.
Charles Darwin and Alfred Russell Wallace worked out the basic mechanism by which evolution occurs (natural selection) based on the observations of living organisms they made on their journeys around the world. In the early part of the 20th century, evolution by natural selection was combined with the growing science of genetics to form the Modern Synthesis, the basic foundation for modern evolutionary biology.
In lectures, we will cover a number of topics including: the nature of evolution; adaptive and neutral evolution; population and quantitative genetics; the origin, maintenance and expression of genetic variation; the evolution of sex and sex allocation; life-history variation; speciation; and comparative methods.
The primary textbook for this course will be Evolution, by Douglas Futuyma. Additional readings will be assigned throughout the course.
The tutorial/seminar hours will be used for two main activities: 1) to discuss thought problems, and provide an opportunity for student debates on readings related to the lecture material; 2) to use computer simulations to deepen understanding of the quantitative aspects of evolutionary biology.
The Science of Scientific Writing
George Gopen and Judith Swan published an execellent article on scientific writing in the November-December 1990 issue of American Scientist (click here). In their article the authors offer advice on good writing by taking account of the expectations of readers.
Thought Problem #1 — 15 January 2009
Darwin used the processes of selection in domestic animals as an analogy for natural selection. As in many things he had no idea of the mechanisms that might be operating; he knew nothing of genetics. Nevertheless, he speculated on how the traits that distinguish domestic animals from their wild relatives may have arisen. He also speculated on the origins of some domestic species. Using Dobney and Larson (2006) and chapter 1 of Origin of Species, choose and explain one example where Darwin seems to have been on the right track and one where he seems to have got it wrong.
Key readings: Dobney K, and Larson G. 2006. Genetics and animal domestication: new windows on an elusive process. Journal of Zoology 269:261-271.
Darwin C. 1859. The Origin of Species. Second Edition. Oxford World Classics Edition, Oxford University Press.
(The text of all six editions of Origin of Species is available free online.)
Thought Problem #2 — 5 February 2009
Nearly 30 years ago, Stephen Jay Gould and Richard Lewontin published a paper that was critical of what they called the “adaptationist programme” in evolutionary biology, where every trait of organisms was seen as the perfect product of natural selection and stories to explain the selective value of traits were paraded as fact. One of Gould and Lewontin’s arguments goes as follows: “Since Darwin has attained sainthood (if not divinity) among evolutionary biologists, and since all sides invoke God's allegiance, Darwin has often been depicted as a radical selectionist at heart who invoked other mechanisms only in retreat, and only as a result of his age's own lamented ignorance about the mechanisms of heredity.” They then proceed to argue how, in fact, Darwin supports their own position.
Was Gould and Lewontin’s article a fair assessment of evolutionary biology? You can take any number of approaches to answering this question: did they accurately represent their sources? Were they selective in the sources they chose? Were others saying similar things? What sort of response did the article generate?
Key reading: Gould, S.J., Lewontin, R.C. 1979. The spandrels of San Marco and the panglossian paradigm: a critique of the adaptationist programme. Proceedings of the Royal Society of London Series B, Biological Sciences 205:581-598.
Thought Problem #3 — 5 March 2009
Early in their article, Cordero and Eberhard state “that further work is needed to determine the importance of male-female conflict in sexual evolution.” It is now six years since this article was published. Have the limitations outlined by Cordero and Eberhard been addressed, or do more recent studies have the same failings they identify?
Key Reading: Cordero C. and Eberhard W.G. 2003. Female choice of sexually antagonistic male adaptations: a critical review of some current research. Journal of Evolutionary Biology 16:1–6.
Thought Problem #4 — 12 March 2009
Orchids provide an excellent example of a type of mutualistic relationship (between plant and pollinator) that has been exploited by one of the partners to its own benefit (witness the huge diversity of orchid species) at the expense of the other partner. Are all mutualisms doomed to breakdown? If not explain some circumstances (empirical or hypothetical) where mutualisms are maintained in the long term.
Thought Problem #5 — 26 March 2009
In her article, West-Eberhard claims critics of her model of phenotypic accommodation leave out “the fact that it does not matter, for the initiation of a novelty, whether the original induction is mutational or environmental; and the fact that environmentally induced traits can initially spread without positive selection…” Is phenotypic accommodation a 21st century incarnation of Lamarckism?
Thought Problem #6 — 3 April 2009
Charles Darwin was a firm believer in uniformitarianism; that is, the evolutionary processes that we see operating today operated in the same way at the same rates over much of the history of life on Earth. The key players of the Modern Synthesis, took this idea and asserted that genetic mechanisms that operate at the level of populations are sufficient over the long term to account for evolution above the level of species. This idea was not universally adopted; many palaeontologists, for example, rejected this idea as reductionist or extrapolationist. What do you think?
Key reading: Penny D. and Phillips M.J. 2004. The rise of birds and mammals: are microevolutionary processes sufficient for macroevolution? Trends in Ecology and Evolution 19:516-522.
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