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Turtle Travels

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TEACHING GUIDES


Science in Paradise: Turtle Travels


On this episode of Frontiers, Alan Alda accompanies biologist Zandy Hillis-Starr into the waters of the Caribbean off St. Croix to capture an adolescent hawksbill turtle. Like other species of sea turtles, the hawksbill is endangered. Here at the Buck Island Reef National Monument, scientists capture and track hawksbill turtles as part of a successful program to preserve the species.

Curriculum Links
National Science Education Standards
Related Frontiers Shows and Activities
Activity 1: I'm Hot, You're Not
Activity 2: Eggstrategy




CURRICULUM LINKS


ENVIRONMENTAL SCIENCE

 

LIFE SCIENCE


reptiles, reproductive strategies




NATIONAL SCIENCE EDUCATION STANDARDS

SCIENCE AS INQUIRY / LIFE SCIENCE
5-8: Reproduction and Heredity, Populations and Ecosystems, Diversity and Adaptations of Organisms
9-12: Biological Evolution, Behavior of Organisms
SCIENCE AND TECHNOLOGY
5-8, 9-12: Understandings about Science and Technology
SCIENCE IN PERSONAL AND SOCIAL PERSPECTIVES
5-8: Populations, Resources and Environments, Natural Hazards, Risks and Benefits
9-12: Population Growth, Natural Resources, Environmental Quality, Natural and Human-induced Hazards, Science and Technology in Local, National and Global Challenges




RELATED FRONTIERS SHOWS AND ACTIVITIES





ACTIVITY 1: I'M HOT, YOU'RE NOT

Research shows that for turtles, as for most reptiles, the cooler the temperature of the nesting site, the higher the number of males that will hatch. Warmer nests produce more females. Biologists must keep this in mind when designing artificial shade to replace the natural shade destroyed by hurricanes. In this activity, explore how different factors affect temperature and relate this to whether a baby turtle will be male or female.

MATERIALS
  • outdoor thermometers (3 minimum)
  • graph paper
  • colored pencils
PROCEDURE

  1. Find three dry areas on the ground near your classroom with the following characteristics:
    a. exposed to the sun all day
    b. exposed to the sun part of the day, shaded part of the day
    c. shaded all day
    Try to find sandy places to model turtle nesting sites. Look for sites that will not be disturbed by anyone but your class, or put a fence or barrier around the site.


  2. Place a thermometer on the surface at each site and record the temperature. Record other factors such as clouds, precipitation and wind.

  3. Continue taking and recording measurements every 30 minutes for the entire school day. You might have to share the responsibility with other science classes and pool the data to construct a complete data table for an entire day.

  4. After you take the data, determine the high, low and average temperature for each site.

  5. Using graph paper and a different colored pencil for each site, construct a line graph with temperature on the vertical axis and time on the horizontal axis.
QUESTIONS

  1. Which area had the highest average temperature? The lowest? How did the environmental factors you recorded in Step 2 affect the temperature?
  2. If a sea turtle built a nest at each site, which site would you expect to have more male hatchlings? Female? Why?
  3. How do you think your temperature results would change if you chose sites that were kept moist? Design an experiment to test your answer.




ACTIVITY 2: EGGSTRATEGY

picture of turtle Part of the hawksbill turtle's reproductive strategy is to return to the same beach every two years, lay hundreds of eggs and leave them to fend for themselves. Only a small number of hatchlings will survive, so it's important to maximize the number of eggs that hatch.

Working on your own or in small groups, use the Web or other resources to investigate reproductive strategies of selected organisms. Some good species to study might include: praying mantis, monarch butterfly, frog (any species), desert tortoise, hummingbird, rattlesnake.

Some animals, like the turtles, lay many eggs and abandon the nest, putting their faith in numbers; other animal species, like humans, bear fewer young but stick around to care for them and assure them a future. For the turtle, most of the energy is expended up front.

Present your findings to the class for comparison. Include information about reproductive strategies, gestation, breeding behavior of parents, developmental cycle of eggs, energy costs. What are the pros and cons of different reproductive behaviors?


EXTENSIONS
  1. What is the advantage of being able to fit more eggs into one nest for the female laying the eggs?

  2. Hawksbill turtles have been found as far south as Belize. How many miles/kilometers is Belize from Buck Island?

  3. What might be the evolutionary advantages and disadvantages of having the gender of a species determined by temperature?

  4. Fishing nets present a hazard for air-breathing sea turtles. If caught, the turtles may drown. Can you design a device that would keep turtles out of nets, yet allow fishermen to catch shrimp? For one example, see the turtle excluder device at: www.nmfs.noaa.gov/prot_res/PR3/Turtles/TEDS.html.

  5. What should you do if you find a nesting sea turtle on the beach? Find out at: www.cccturtle.org/threats.htm#what.





 

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