Biology 3315
Vertebrate Zoology
Take-Home Essays – Exam 2
Fall 2008
General Information
You can choose only one of the four papers listed below for your summary. At the end of this document
are the questions associated with each of the papers. Your essay is due at the beginning of the exam on
Monday.
1. Hillenius, W. J. and J. A. Ruben. 2004 The evolution of endothermy in terrestrial vertebrates.
Who? When? Where? Physiological and Biochemical Zoology 77:1019-1042.
2. Farmer, C. 1997. Did lungs and the intercardiac shunt evolve to oxygenate the heart in
vertebrates? Paleobiology 23:358-372.
3. Lips, K. R. 1998. Decline of a tropical montane amphibian fauna. Conservation Biology 12:106117.
4. Long, J. A. and M. S. Gordon. 2004. The greatest step in vertebrate history: A paleobiological
review of the fish-tetrapod transition. Physiological and Biochemical Zoology 77: 700-719.
Format
Your essay must be typed. It is limited to the two pages and the pages must be stapled together. It must
be double-spaced with a 12 point font and top, bottom and side margins that are at least 1”. Be sure to
put your student identification number at the top of the page. DO NOT PUT YOUR NAME ON YOUR
ESSAY! Points will be deducted if you do not follow this format explicitly.
Evaluation Criteria
Your essay should be directed toward imagined readers who are not familiar with the issue. The purpose
of the essay is to develop a thesis statement about an issue and offer clear and logical support for your
thesis statement. A good essay will enable the reader to clearly understand the issues being discussed,
as well as your position on the issue.
The grading criteria for the essay are (1) accuracy of content, (2) comprehensiveness and balance,
and (3) clear sentence structure with good transitions.
Accuracy of Content
This refers to facts presented in the essay. Unless explicitly stated, you do not need to cite specific
literature in essays. However, you must be sure that the information is factual, based on credible sources
of information.
Comprehensiveness and Balance
Comprehensiveness refers to the thoroughness of coverage of the issues, presence and clarity of the
thesis statement, and how convincingly you support your thesis statement. Essays must address the
major issues related to the essay topic. That does not mean that an essay considers every possible facet
of an issue. There is not enough space for minor or tangential issues. The writer must decide what is
important and write succinctly about those issues.
Balance has 2 components: 1) How much space (i.e. how many words) is allotted to each of the major
issues that are covered in the body of the paper, and 2) How much space is allotted to the introduction,
body and conclusion. Writers must judge the importance of each issue or concept and apportion space
proportional to their importance. Writers must also make certain that the introduction, body, and
conclusion are appropriate in length. The body should comprise the majority of the essay because that is
where the issues are laid out and the supportive arguments developed. The arguments must convincingly
support the thesis statement. The introduction must be brief, but provide an adequate introduction to the
issues. Lastly, the conclusion is typically the shortest section. A good conclusion should provide a terse
and unambiguous close to the essay, which is easier said than done.
Clear Sentence Structure with Good Transitions
Because essays are short in length, each sentence must be carefully arranged and edited for maximum
clarity. This will not happen on your first attempt. It takes much editing to produce a succinct and clear
essay. Concepts in essays should flow smoothly from one idea to the next. Therefore, good transition
sentences are essential. Keep in mind that smooth transitions result more from clear organization than
writing prowess. If an essay is well thought out, the ideas will naturally follow each other.
Nature of the “Questions”
For each of the readings, I have listed the major points that need to be addressed. These points should
not be considered as an “outline” for your essay, but rather as a check list of key issues that need to be
addressed.
1. Hillenius, W. J. and J. A. Ruben. The evolution of endothermy in terrestrial vertebrates.
Who? When? Where? Physiological and Biochemical Zoology 77:1019-1042.
After reading the article, compose a summary that addresses the following questions. When appropriate,
incorporate material from your lecture notes or the Pough et al. text to support your answer.
 Hillenius and Rubin argue that the earliest evidence for endothermy in the mammalian lineage
appeared in the Late Permian period while a similar type of evidence appeared in birds during the
Cretaceous. Your essay should clearly explain what this evidence is and why the authors
consider it such strong evidence of the origins of true endothermy in these two lines of terrestrial
vertebrates.
2. Farmer, C. 1997. Did lungs and the intercardiac shunt evolve to oxygenate the heart in
vertebrates? Paleobiology 23:358-372.
After reading the article, compose a summary that addresses the following issues. When appropriate,
incorporate material from your lecture notes or the Pough et al. text to support your answer.
 The traditional view of the evolution of the lung links its respiratory function to aquatic habitats that
were either anoxic or very low in dissolved oxygen. Farmer discounts this argument and
proposes an alternative pathway to lungs. Briefly summarize the evidence she presents
countering the “anoxic environment” hypothesis, then explain her alternative hypothesis.
3. Lips, K. R. 1998. Decline of a tropical montane amphibian fauna. Conservation Biology
12:106-117.
After reading the article, compose a summary that addresses the following questions. When appropriate,
incorporate material from your lecture notes or the Pough et al. text to support your answer.
 Karen Lips was one of the first researchers to clearly document wide-spread amphibian decline in
a single area. In her article, she uses her data to narrow the range of possible factors causing the
declines to either biotic pathogens/environmental contaminants or a combination of these factors
plus climate change. How does she arrive at these conclusions and do you find here arguments
convincing?
4. Long, J. A. and M. S. Gordon. 2004. The greatest step in vertebrate history: A
paleobiological review of the fish-tetrapod transition. Physiological and Biochemical
Zoology 77: 700-719.
After reading the article, compose a summary that addresses the following issues. When appropriate,
incorporate material from your lecture notes or the Pough et al. text to support your answer.
 Long and Gordon define five groups they consider important in understanding the evolutionary
transition from fish to tetrapod. What were the major anatomical changes associated with each of
these five groups? What is heterochrony and what role does it play in Long and Gordon’s
explanation?