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Turtles: Exploring data
in turtle population dynamics

Integrating Digital
Technologies

Years 5-6; 7-8

DT+ Mathematics; DT+ Science


The number of eggs a female turtle lays in her lifetime influences the health of that species population. In this lesson we look at modelling data related to the number of eggs a female turtle lays in her lifetime, using real scientific data. Explore ways to model, interpret, represent and present data, creating an infographic to raise awareness about turtle conservation.

This lesson was created and developed in partnership with with Pawsey Supercomputing Centre and Western Australian Marine Science Institution (WAMSI) Kimberley Marine Research Program.. Turtle data was sourced from the WAMSI project, which is funded by the Western Australian State Government and research partners. Data is licensed under the Creative Commons BY-NC-SA 2.5 AU licence.



Question: How many eggs might a female turtle lay in her lifetime?

Suggested steps

Learning hook

  1. Use a quiz to stimulate interest in marine turtles and discussion of some key concepts.
  2. Use a suitable learning hook to engage students in analysing and interpreting real data about marine turtles. Here are some ideas:
    • Share experiences of observing turtles when holidaying or visiting museums or aquariums.
    • Use a relevant resource such as Marine turtles in Australia to show images of different turtle species. Discuss what students know about turtle habitats, conservation status (vulnerable/endangered) and the cultural and social values of turtles for Aboriginal and Torres Strait Islander people.
    • Ask: What affects turtle population numbers?
    • ask students to hand draw a picture of a turtle thinking about its features and how these features help it survive.
      Compare their drawings to an image of a turtle or this flatback turtle in 3D.

Marine scientists

  1. Discuss the work of scientists who work in conservation, surveying populations to ensure relevant data is collected, analysed and used to inform management strategies. Refer to career profiles for Sabrina Fossette of the Western Australian Department of Biodiversity, Conservation and Attractions and Blair Bentley, a postdoctoral researcher.


    Sabrina Fossette

    Blair Bentley


Student task

  1. Use the slide deck, Marine turtle: nesting. The slide deck introduces the question: How many eggs might a female turtle lay in her lifetime? It provides a guide to scaffold students’ mathematic, scientific and technological thinking. To answer the question students need to know the total number of eggs a turtle lays in a season and how many seasons it nests and lays. Provide time for students to work out their own method of calculation.

    Image of the front page of the student task, which has the words: Marine turtles nesting, student task


Using data in their calculation

  1. Provide students data when they attempt to calculate the number of eggs a female turtle lays in her lifetime.

    Use the following data for a leatherback turtle to complete the calculation.

    • Species: Leatherback
    • Current age: 50
    • Breeding age 15
    • Years between nesting: 5
    • Average number of eggs per clutch: 82
    • Average number of clutches per season 6.

Breaking down the calculation visually

  1. Once the students have has a go at their calculation, use the flow chart to assist students to work out the calculation. Compare this with students’ initial thoughts on the calculation.

    The flow chart provides an opportunity to discuss this as a form of algorithm.

    How many eggs might a female turtle lay in her lifetime?' flowchart. To calculate the number of seasons it lays, take the current age and minus the breeding age to equal the maximum number of breeding years. Divide this by the years between nesting, which equals the number of season it lays. To calculate the total number of eggs per season, take the average number of eggs per clutch and multiply it by the number of clutches person season. This equals the total number of eggs per season. Multiply the number of seasons it lays by the total number of eggs per season to get the number of eggs a female turtle lays in her lifetime. Then ask yourself the question: 'What does this mean if only 1 in 100 survive?'
    How many eggs might a female turtle lay in her lifetime?' flowchart that has been completed. To calculate the number of seasons it lays, take the current age (for example 50) and minus the breeding age (for example 15) to equal the maximum number of breeding years (in other words 35). Divide this by the years between nesting (for example 5), which equals the number of season it lays (in other words, 7). To calculate the total number of eggs per season, take the average number of eggs per clutch (for example 82) and multiply it by the number of clutches person season (for example 6). This equals the total number of eggs per season (in other words 489). Multiply the number of seasons it lays (7) by the total number of eggs per season (489) to get the number of eggs a female turtle lays in her lifetime (3423). Then ask yourself the question: 'What does this mean if only 1 in 100 survive?'

    Discuss the differences regarding the total number of eggs laid in a lifetime if certain factors were changed; for example:

    • if years between nesting were shorter or longer
    • if the average eggs per clutch were lower or higher
    • if the average number of clutches per season were lower or higher.

    Talk about the likelihood that only one in 1000 turtles survive. How many of a female turtle’s offspring would be likely to survive, based on those odds? (3423/1000 = 3.423 or 3 offspring).


Data modelling

  1. Use the Turtle hatchling production modeller to calculate how many eggs a female turtle lays in her lifetime. Discuss the use of the spreadsheet to model an event like turtle hatchling survival. Discuss the green cells with inputs using drop down menus. Analyse the changes to the output cells. The spreadsheet allows students to enter different inputs to look for patterns in the data and predict outcomes based on changing parameters such as age of the turtle, breeding age, years between nesting, number of clutches per season and adjust the chance of survival of a hatchling.

    (Click on the image to expand it in a new window.)

    This a screenshotted image of the first page of the 'Turtle hatchling production modeller' spreadsheet. Students are being instructed to use the leatherback turtle as an example to explore hatchling data. The instructions state: Use the drop down menus to change turtle age, breeding age, years between nesting, and average number of clutches in a season. Students are asked to consider what impact changing each of these values will have on the number of eggs laid in a lifetime and the number of offspring that will survive.
  2. The Turtle hatchling production modeller allows for differentiation.



  3. Share students’ modelling of the data and what they learned. Ask them to consider global issues such as:
    • plastics pollution in the ocean
    • climate change and impact of rising temperature on turtle nesting.

Creating an infographic

  1. Ask students to do some further research and create an infographic about turtle conservation incorporating the data they used in their data modelling.

Discussion

Digital Technology focus

  • How can spreadsheets be used to model population data?
  • What is the benefit of using a spreadsheet to model the data?
  • How can you design the spreadsheet to be user friendly?

Science focus

  • What factors affect the turtle population?
  • The likelihood is that only one out of a thousand hatchlings will survive. How does that affect the population numbers of marine turtles? What might happen if that chance of survival decreased?

Mathematics focus

  • How do you calculate the number of eggs a turtle lays in her lifetime?
  • What operations do you include in the process?

Why is this relevant?

In Digital Technologies, students need to interpret data. To do this it helps to organise the data in some way; for example, in a table under relevant headings. In a spreadsheet, students can sort and filter data to look for patterns or trends.

Students present data to reveal information and convey meaning. Students can do this by developing visualisations such as graphs, tables and plots to reveal trends. In years 7–8, students model objects and events. This task allows students to model population data and infer relationships and effects of changing inputs.