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A Tale of Three Lice

A Case Study on Phylogeny, Speciation, and Hominin Evolution



Co Authors:

Erin Barley
Department of Biological Sciences
Simon Fraser University
ebarley@sfu.ca

Joan Sharp
Department of Biological Sciences
Simon Fraser University
jsharp@sfu.ca

Abstract:

This “clicker case” explores the questions of when hominins lost their body hair and began wearing clothing by examining the surprising phylogeny of human head, body, and pubic lice. Students are led through the scientific process as they are asked to think about hypotheses, predictions, results, and conclusions, and learn about phylogeny, speciation, and hominin evolution. The case is presented class using a set of PowerPoint slides (~1.5MB) that includes multiple-choice questions students answer using personal response systems (“clickers”). It could be adapted for use without these technologies.  Developed for a general biology class focusing on evolution and ecology, the case is also suitable for use in a non-majors introductory biology course.

Objectives:
  • Read phylogenetic trees and use inferences from these trees to support or reject hypotheses.
  • Explain how divergence of ape taxa (including humans) drove speciation in their louse parasites.
  • Explain why a host is the major component of the environment of their obligate parasites and describe how primate lice are adapted to their hosts.
Keywords: Human evolution; louse; lice; Pediculus humanus capitus; Pediculus humanus corporis; Phthirus pubis; hominin; primate; ape; chimpanzee; insect; entomology; parasite; host; co-speciation; phylogeny; cladogram; hypothesis testing
Topical Area: Scientific method
Educational Level: High school, Undergraduate lower division
Formats: PDF, PowerPoint
Type/Method: Clicker, Interrupted
Language: English
Subject Headings: Evolutionary Biology   Biology (General)  
Date Posted: 10/29/09
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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This is awesome and timely! I’m doing human evolution in my general biology class this week and I’ve been looking for just such a case. I have one concern that I would like to past back to the authors.

I know that there are disagreements among paleoanthropologists, but I’m finding that most of my sources include Pan (chimps) in the Hominini Tribe. This case appears to exclude chimps from the Hominini (commonly refered to as Hominins).

  • Kingdom: Animalia
  • Phylum: Chordata
  • Class: Mammalia
  • Order: Primates
  • Superfamily: Hominoidea
  • Family: Hominidae
  • Subfamily: Homininae
  • Tribe: Hominini
  • Subtribe Panina: Genus Pan (chimp-like) Subtribe Hominina: Genus Homo (human-like) + Extinct Genera:

    • Paranthropus
    • Australopithecus
    • Sahelanthropus
    • Orrorin
    • Ardipithecus
    • Kenyanthropus



Caryn Self-Sullivan, PhD
Department of Biology
Georgia Southern University
Statesboro, Georgia 30458
cselfsullivan@georgiasouthern.edu
10/29/2009
Authors’ Reply

Thanks for your comments on our case.

There is still a dispute among paleoanthropologists about the use of the term hominin. The term is used for the taxonomic level of tribe and the dispute addresses how closely related chimps and humans are. The most common usage is that used in our case, based on the assumption that chimp and human lineages are different tribes and using hominin for the human lineage. There are two competing usages. The one you use assumes that chimp and human lineages belong to one tribe, the hominin. Finally, a third group of paleoanthropologists argues strongly that chimps and humans belong to the same genus and refers to chimps as Homo troglodytes. We have added a note about this controversy to the case teaching notes.


Erin Barley and Joan Sharp
Department of Biological Sciences
Simon Fraser University
Burnaby, British Columbia Canada
ebarley@sfu.ca jsharp@sfu.ca
11/5/2009




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