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An Unusual Case of Animal Reproduction

Co Authors:

Joann B. Powell
Department of Biological Sciences
Clark Atlanta University

Elethia W. Tillman
Department of Biology
Spelman College


This case study in human reproduction follows Andrea, a college biology student who discovers she is pregnant with twins, but is not sure who the father is. Students are presented with a variety of signs, symptoms, and physiological information that they interpret by researching and answering a series of questions. Students gain an understanding of female reproductive cycles by investigating this unusual pregnancy. Students also discuss the importance of safe sex practices and contraception. Developed for an undergraduate general biology course, the case also could be used in women's studies, human health and sexuality, or advanced high school biology courses as well as upper-division anatomy and physiology courses. There also is an opportunity to discuss the biotechnology involved in DNA/paternity testing (DNA extraction, enzyme digestion, and gel electrophoresis).

  • Distinguish between asexual and sexual reproduction.
  • Define parthenogenesis and describe conditions that favor its occurrence.
  • Explain the function of pheromones in mate attraction.
  • Describe the major differences between oogenesis and spermatogenesis.
  • Define conception, gestation, and parturition.
  • Describe the changes that occur in the mother and the developing embryo during each trimester of a human pregnancy.
  • Explain the role of embryonic hormones during the first few months of pregnancy.
  • List the various methods of contraception and explain how each works.
Keywords: Human reproduction; menstrual cycle; pregnancy; ova; estrogen; progesterone; fertilization; heteropaternal; superfetation; superfecundation; oogenesis; fraternal twins; pheromones; sex; contraception; DNA testing
Topical Area: Science and the media
Educational Level: Undergraduate lower division, Undergraduate upper division, Graduate
Formats: PDF
Type/Method: Analysis (Issues), Discussion, Interrupted
Language: English
Subject Headings: Biology (General)   Anatomy   Physiology   Molecular Biology   Biotechnology  
Date Posted: 12/8/2011
Date Modified: N/A
Copyright: Copyright held by the National Center for Case Study Teaching in Science, University at Buffalo, State University of New York. Please see our usage guidelines, which outline our policy concerning permissible reproduction of this work.

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