BISC 495-010, Evolution, Spring 2007

Term paper

Choose a topic

You are required to write a term paper on some aspect of evolutionary biology. On Friday, March 2, you must turn in a typed, one- or two-sentence description of the topic you have chosen, along with a list of three articles from the primary scientific literature on the topic, in the format shown below. This will be worth two percent of your overall grade for the class.

Your term paper must consist of a thorough review of the literature on your chosen topic. It would be impractical to do a thorough review on a broad topic, such as "The invasion of land by aquatic animals," because there would be hundreds of relevant papers to read. Instead, you should pick a topic that is narrow enough that there are only a couple dozen or so relevant papers. "The invasion of land by crabs" might be narrow enough.

The easiest way to see if your topic is narrow enough (but not so narrow that there are only a couple papers on it) is to find one paper, then use the Web of Science (see the Guide to searching for biological literature for instructions) to see which older papers it cites, and which newer papers cite it. Pick out a couple of the most relevant papers from those two lists, and see which papers they cite, and which papers cite them. If you start to see the same relevant papers over and over, that's a good sign that you've got a manageably narrow topic.

But how do you find that first paper on your topic? If you have a topic in mind, you may do a topic search in the Web of Science. For example, if you're interested in spiders, you could do a search for evolution and spiders. There are 388 references listed, so you'll need to narrow it down. Skimming through the list of titles, you see a paper by R.G. Gillespie called "Geographical context of speciation in a radiation of Hawaiian Tetragnatha spiders (Araneae, Tetragnathidae)." Adaptive radiation--where one species evolves into many species to fill a bunch of empty niches--is pretty cool, so you look further. The Gillespie paper cites 50 references; skimming through their titles, it looks like 12 are about Hawaiian spiders. You pick out one of the older and more relevant-sounding papers, Gillespie et al. (1994), "Multiple origins of a spider radiation in Hawaii." It's been cited 43 times, and when you look at the list of papers that cite it, you see many of the same Hawaiian spider papers. This would be a good topic--you've already found most of the relevant papers, and you can see that there are enough, but not too many.

But what if you can't think of a topic? You could browse through your textbook to see if anything sounds interesting. For example, page 310 mentions amphipod crustaceans that live in caves and are evolving smaller eyes. That's amazing! It cites a paper by Jones and Culver (1989). You could look up the Jones and Culver paper in the reference list at the back of the book, then look it up in the Web of Science (do a topic search on a phrase from the title), and off you go.

You could also come up with a topic from something you've read in a newspaper or magazine, or heard about in one of your other classes. You could poke around in some blogs that focus on evolution (among other things), such as The Panda's Thumb, The Loom, or Evolgen, or browse around in Wikipedia. And if you're interested in the controversy between evolutionary biology and creationism, the Talk Origins FAQ is a good place to start.

Literature research

On Friday, March 16, you must turn in a typed list of references on your topic. This will be worth five percent of your grade. The references must be in alphabetical order by first author, and they must be in the format shown at the bottom of this page.

Please attach your graded previous assignment (the topic choice and list of three papers) to the back of this asssignment. If you have errors in your reference format, you'll be penalized less severely if I see that you've made improvements to the format from the first assignment to this one. I also want to see whether you've followed any advice I gave about broadening or narrowing your topic.

Your list of references should be thorough, including everything on your specific topic. Look at the initial three papers you found on the topic, and find every relevant reference that they cite. Also look up some of the older papers in the Web of Science and see who has cited them. Keep doing this--for every paper you get, see who they cite and who has cited them--until you're not seeing anything new.

Your reference list will be graded based on its format (see the examples below) and its thoroughness. If I can quickly find references that are very relevant to your topic that you haven't listed, you'll get points off. For many topics in evolution, even very old references are important. In some other fields of biology, such as cell and molecular biology, laboratory techniques are so important and improve so rapidly that papers from 20 years ago are only of quaint, historical interest. Advances in evolutionary biology often depend less on technical advances and more on synthesizing scattered bits of information, and sometimes that information is found in papers that are many decades old. So don't limit yourself to recent publications, even though the older ones may be harder to obtain.

As you assemble your list of references, you should start obtaining them so you can read them. Some will be available online, some will be in print in the Morris library, and you'll have to obtain some by Interlibrary Loan. Don't wait until the last minute to obtain your references; the ones you get by Interlibrary Loan, in particular, may take a while to arrive.

Your reference list must contain at least 25 references. You may include web pages on your list, but they do not count towards the 25 references. You may not include Wikipedia; it can be a valuable place to start looking for some kinds of information, but you should trace the information back to its original source and cite that instead. If you are having trouble finding 25, keep in mind that you'll want some more general references in addition to everything on your narrow topic. For example, if you were researching the adaptive radiation of Hawaiian spiders, you'd want a few references on the general topics of adaptive radiations, spiders, and the geologic history of the Hawaiian islands, in addition to all of the references you can find on the adaptive radiation of Hawaiian spiders.

The finished paper

Your paper is due Friday, April 27. Three points (out of a possible 18) will be deducted for each weekday that the paper is late. If you turn the paper in on Monday, April 30, it will be worth a maximum of 15 points, 12 points if turned in on May 1, etc. If you will not be in class on April 28, you may turn the paper in early, put it in my mailbox in Wolf Hall, or bring to my office (322 Wolf) and slide it under my door if I'm not there.

You must attach the graded reference list to your paper, so I can see whether you've found the additional references I suggested when I graded it.

The paper is worth 18 percent of your grade. It must be typed and have at least 15 pages of double-spaced text, not including figures or the reference list. Do not use unusually wide margins, large font, increased line spacing, etc. to make the 15-page limit; just grit your teeth and write some more. Figures are useful, and you should definitely have them, but they don't count towards the 15 pages; thus if you have four half-page figures, your paper must be at least 17 pages long.

Your paper should summarize the literature on your topic. It should be clearly organized, either chronologically or by sub-topic. For example, the Hawaiian spider paper could start with the oldest studies on adaptive radiation in Hawaiian spiders, then work up to the most recent research; or it could have different sections for different groups of spiders, or different islands, or different adaptations.

In addition to the results of the different studies, describe how those results were obtained. What kinds of experiments and observations did people make? How did they interpret them? What were the competing hypotheses? Have later researchers interpreted earlier results in different ways, or come up with new hypotheses?

Do not use jargon that your classmates would not understand without explaining it. In particular, do not use phrases that you have read if you don't understand them. If you can't figure something out, ask me and I'll try to help.

The reference list must include at least 25 references, strictly following the format shown below. You may include web pages, but they don't count towards the minimum of 25. You may not cite Wikipedia; it can be a useful first step in researching a topic, but for this paper, you should look at the original references cited by the Wikipedian rather than trusting their interpretation.

Revised version of the paper

I'll return your graded paper on April 30, May 2, or May 4. If you get more than 3 points off, you must fix the problems and turn in a revised version (along with the graded original) on Friday, May 12. Any problems that aren't fixed in the revised version will get further points off. If you were unable to make some of the improvements I suggested, you may include a typed note explaining why. For example, if you did a paper on the Hawaiian spiders and I wrote on your first draft, "You should include a picture of the amazing spiny legs of this spider--there must be one in Gillespie et al. (1994)," you could write a note that said "There isn't a figure of the spiny legs in Gillespie et al. (1994) or anywhere else that I could find."

Text format

You must follow these formatting rules. They may seem picky, but following them demonstrates your ability to follow instructions exactly, an important skill for both research biologists and medical professionals.


Copying someone else's writing and pretending that it is yours is a serious violation of the University's Code of Conduct. If you copy text from a book, article, web page, or other source, you will receive a 0 for the assignment. If the copying is particularly extensive or egregious, you will receive an F for the course.

Here's a passage from Hudson et al. (1987):

The presence of a balanced polymorphism in the coding region of Adh could explain the relatively high level of polymorphism observed in that region. The existence of a balanced polymorphism at a single site can lead to higher levels of neutral polymorphism at linked sites (Strobeck 1983). The reason this can occur is that during the time that the balanced polymorphism is maintained by selection, new mutations will tend to accumulate in the region tightly linked to the selected site.

Copying these words exactly is plagiarism, even if you put "(Hudson et al. 1987)" at the end. It's also plagiarism if you just change a few words, like this:

A balanced polymorphism in the coding region of Adh could explain the high level of polymorphism in that region. The existence of a balanced polymorphism at a single site can cause higher levels of neutral polymorphism at linked sites (Strobeck 1983). This is because during the time that the balanced polymorphism is maintained by selection, new mutations will accumulate in the region tightly linked to the selected site (Hudson et al. 1987).

Instead of copying or trying to rewrite a passage, you should paraphrase it, summarizing the information in your own words:

There is an area around an amino acid polymorphism in Adh that has a relatively high level of silent polymorphism. This may be caused by balancing selection (Hudson et al. 1987).

If you find yourself staring at a sentence in a paper, struggling to think of a way to rearrange the words in that sentence just enough to keep it from being plagiarism, you're going down the wrong path. Read several paragraphs, set them aside, then write down a summary of the main points. Don't try to write about things you don't understand.

Direct quotes

In papers in other fields, such as English or history, it is common to use many direct quotes, putting phrases or sentences from sources in quotation marks. This is because the exact words are important; if you're writing a paper on "The meanings of dust in Kafka's Metamorphosis," it's important to quote exactly what Kafka wrote about dust; his words are your "data," and you want to represent the data accurately. As long as you cite the source correctly, using quotes in quotation marks is not plagiarism.

In scientific writing, however, we rarely use direct quotes. Partly, this is just a cultural tradition; partly, it's because when scientists cite another paper, it's because they're writing about the information in the paper, and the exact words used to convey that information are not important. You may use a quotation or two, if you come across a particularly pithy statement of an important concept, but you will get points off for excessive use of direct quotes.

Citation format

Citations in the text must follow the author, year format: (Lewontin and Hubby 1966; Kreitman 1983; Hudson et al. 1987). Use "et al." for three or more authors. If the authors' names are part of the sentence, they are not in parentheses: "Lewontin and Hubby (1966) surveyed allozyme polymorphism in Drosophila pseudoobscura."; "The fly species Drosophila pseudoobscura has extensive allozyme polymorphism (Lewontin and Hubby 1966)." If there are multiple citations in a single set of parentheses, they are in chronological order from oldest to most recent.

Do not give the article title or journal name in the body of the paper. Don't say, for example, "Richard Hudson, Martin Kreitman and Montserrat Aguadé, in a paper titled 'A test of neutral molecular evolution based on nucleotide data,' published in Genetics in 1987, developed a method to detect selection using variation in the ratio of polymorphism to divergence." Instead, say "Hudson et al. (1987) developed a method to detect selection using variation in the ratio of polymorphism to divergence."

Web pages should be cited using the author and year, if that information is available; this page would be cited as McDonald (2007), for example. If the web page does not say when it was written, say "undated." If there's an institutional author, list that; UD's home page could be cited as University of Delaware (2007), for example. If there's no apparent author of any kind, say Anonymous.

The Literature Cited section must include all of the literature cited in the text, alphabetically by first author, in the following format. For journal articles, the format consists of the following, in order:

Books are cited the same as journal articles, except instead of the journal, volume and page numbers, you give the publisher and the publisher's city. Do not abbreviate book titles. Book chapters are the same as journal articles, except instead of the journal, volume and page numbers, you give the pages, the editors of the book, the title of the book, publisher and city.

Web pages can be tricky to cite, as it's often not clear what the author, title, and year are. Follow the format shown below as best you can.

Here are some examples of citation format:

Journal articles

Hudson, R. R., M. Kreitman, and M. Aguadé. 1987. A test of neutral molecular evolution based on nucleotide data. Genetics 116:153-159.

Methe, B. A., K. E. Nelson, J. W. Deming et al. (24 co-authors). 2005. The psychrophilic lifestyle as revealed by the genome sequence of Colwellia psychrerythraea 34H through genomic and proteomic analyses. Proc. Natl. Acad. Sci. USA 102: 10913-10918.


Sokal, R. R., and F. J. Rohlf. 1995. Biometry. W.H. Freeman, New York.

Book chapters

Hall, B. G. 1983. Evolution of new metabolic functions in laboratory organisms. Pp. 234-257 in M. Nei and R. K. Koehn, eds. Evolution of genes and proteins. Sinauer Associates, Sunderland, Mass.

Web pages

Gregory, T.R. 2007. Animal Genome Size Database.

University of California Museum of Paleontology. 2007. Understanding evolution.

Anonymous. Undated [viewed January 28, 2007]. Frequently asked questions about creationism and evolution.

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