Adaptation – Maths

Survival of the fittest

This task will enable students to analyse and compare data by calculating the mean, median and mode of two data sets and the standard deviation.

Provide students with Handout 1. Students organise the data to interpret and report on any trends observed, e.g. students may choose to create a table showing frequencies of a range of snake lengths and graph the data.

Students use the data provided in Handout 1 to find the mean, median and mode length of Black tiger snakes on each island. Students identify which method is most suitable to use and why.

Guide questions:

• Is the data mostly grouped around a common range with some data showing extreme values? Which method would be most appropriate in this case?
• The median is the middle value – when would you use this method?
• The mode relates to a number in the data that occurs most often - when would this be useful?
• Which method do you think would be the most reliable? Which would use every number in the data?

Ask if the data shows whether there is a significant difference in the average length of the snakes.

The data in Handout 1 can be used to calculate the standard deviation for the variation in length of adult tiger snakes between the two island populations. Students may use a formula to calculate the standard deviation. Alternatively students could use a standard deviation calculator available online.

Resources

Snake length vs. prey weight

This task will enable students to determine if there is a relationship between two variables by creating a scatter plot graph.

Provide students with Handout 2. Students plot length against prey weight to create a scatter plot graph. They interpret the graph to see if there is a relationship between the length of the snakes and the weight of the prey. Discuss different associations.

Resources

Black tiger snake population simulation

This task will enable students to determine the probability of various types of offspring based on a simulation game.

Provide students with Handout 3. Use the data to estimate the probability of offspring being a particular phenotype - large, medium or small - given a population starting with the same number in each phenotypic group.

For each year calculate the percentage of large, medium and small snakes in the total population.

Guide questions:

• Does the chance of survival of a Black tiger snake species change from year to year? Why?
• Does the chance of survival of an individual snake change from year to year?

Resources