Fig. 5.31. (A) Carapace (B) Plastron
Image courtesy of New York State Department of Environmental Conservation
Title
Activity: Identifying Sea Turtles
NGSS Science and Engineering Practices
NGSS Crosscutting Concepts
NGSS Disciplinary Core Ideas
Table of Contents
Materials
- Fig. 5.31. Basic sea turtle anatomy
- Table 5.3
- Table 5.4
- Table 5.5
Fig. 5.31. (C) Nuchal scute placement (D) Prefrontal scales
Image courtesy of New York State Department of Environmental Conservation
Procedure
- Before beginning the activity, answer question 1 in the Activity Questions below.
- Familiarize yourself with sea turtle anatomy (Fig. 5.31; Table 5.3).
- Use the sea turtle dichotomous key (Table 5.4) to identify each specimen in Table 5.5 to species level. Record the key steps taken for each identification.
- Compare your results with those of your classmates.
| Specimen | Key steps and identify |
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Image
 Image caption
Body Image copyright and source
Image courtesy of Andy Bruckner, National Oceanic and Atmospheric Administration (NOAA)
Image
 Image caption
Head Image copyright and source
Image courtesy of Jean-Marie Hullot, Fotopedia |
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Image
 Image copyright and source
Image courtesy of Claudia Lombard, U.S. Fish and Wildlife Service (USFWS) |
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Image
 Image copyright and source
Image courtesy of, U.S. Fish and Wildlife Service (USFWS) |
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Image
 Image caption
Body Image copyright and source
Image courtesy of Ecocentrik Guy, Dinosoria
Image
 Image caption
Head Image copyright and source
Image courtesy of stokesrx, Flickr |
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Image
 Image copyright and source
Image courtesy of Natural Environment Center, Mackay Regional Council |
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Image
 Image copyright and source
Image courtesy of Professor Charles R. Peterson, Idaho State University |
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Image
 Image copyright and source
Image courtesy of Jennie Mallela, Flickr |
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Image
 Image caption
Body Image copyright and source
Image courtesy of Donkeyshot, Wikimedia Commons
Image
 Image caption
Head Image copyright and source
Image courtesy of National Park Service |
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Image
 Image caption
Body Image copyright and source
Image courtesy of Kydd Pollock, U.S. Fish and Wildlife Service (USFWS)
Image
 Image caption
Head Image copyright and source
Image courtesy of Brocken Inaglory, Wikimedia Commons |
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Image
 Image caption
Body Image copyright and source
Image courtesy of Strobilomyces, Wikimedia Commons
Image
 Image caption
Head Image copyright and source
Image courtesy of Dr. Brian Gratwicke, Smithsonian Conservation Biology Institute (SCBI) |
Activity Questions
- 1. The dichotomous key in Table 5.4 only works for sea turtles.
- Write a definition for “sea turtle” in your own words.
- Are you certain that all of the animals depicted in Table 5.5 are sea turtles? Why or why not?
- Think of another way to graphically represent the information in the sea turtle dichotomous key (Table 5.4). Examples may include a flow chart, tree diagram, or another graphical representation to better visualize the process of identifying organisms.
- In your own words, explain how a biologist would use a dichotomous key to identify an unknown organism. Write your explanation as if you were teaching your younger sibling how to use a dichotomous key.
- One common difficulty with species identification using dichotomous keys is learning new biological terms. These terms are used to describe specific anatomical parts of an organism clearly and concisely. Use your own words to describe the following turtle anatomical terms:
- carapace
- plastron
- costal scute
- Among the seven living species of sea turtles, select two that appear to be the most similar. Do you think these two species share a close evolutionary relationship? Why or why not?
- The dichotomous key provided in Table 5.4 identifies and classifies sea turtles based on their physical features or morphology. However, this method might not reveal the evolutionary relationships of these seven turtle species.
- Do you think a dichotomous key based on physical features (morphology) reflects the true evolutionary history and relatedness between the species? Why or why not?
- When might a morphology-based classification system conflict with a system based on genetic evidence?
- Compare this dichotomous key to others you have used.
- How are they similar in terms of their complexity, detail, and difficulty-of-use?
- How are they different?
