Genetic Rescue to the Rescue

Students interpret a series of images (rebus puzzle) to determine the focus of this lesson.

What we call a "panther" actually means a lot of different, very distinct types of cat.

▶ The Return of The Florida Panther explores the plight of the panther through the lens of different stakeholders (e.g. urbanites, ranchers, and Native Americans).

Students work with a partner, in a group, or individually, as you prefer to fill out a table with biological, social, and economic impacts caused by the extinction of Florida panthers. After sharing/discussing as a class, they spend the rest of class reflecting individually about different stakeholder perspectives and summarizing take-homes.

For Polymath Puzzle #1, students look at a series of shapes with different patterns and colors and they must count how many different "traits" can be observed. For puzzle #2, students are shown two groups of traits and they must decide which group exhibits greater variation.

Spend some time going through the slides with students to ensure a solid understanding of dominant and recessive traits. These form the basis of why the Florida Panther is experiencing genetic crisis.

In this activity, students simulate matings between panthers in a small and a large population. The slides guide students through understanding the 3 traits that we will be studying: kinked tails (a bone defect), a heart defect (where kittens are born with a hole in the septum), and cowlick (a strange pattern in the fur). By simulating matings in a large population (where recessive traits will be less common) and a small population (which parallels inbreeding in endangered populations), students should recognize how population size affects overall health of a species.

Each group should have 2 envelopes with cutouts of 15 panther cards (1 set sampled from a small population; 1 sampled from a big population). Students start by drawing a pair of parents from the small population. They fill in Table 1, practicing with assigning genotypes and phenotypes.

If a parent is homozygous (e.g. TT or tt), they only have one allele to pass on. In cases of heterozygous parents (Tt), you can have students flip a coin to determine which allele gets passed on.

First students fill out Table 3, with three matings (parent and offspring genotypes), counting up recessive phenotypes. They then do the same thing in Table 4, drawing cards from the "Big Population," which has many fewer recessive genotypes.

You will need to have Table 5 drawn on the board (or use a spreadsheet) to allow groups to record their data.

Students will then calculate the total number of recessive phenotypes out of the total possible to get a percentage. They should then reflect on why the percentage of recessive traits is higher in the small population and why it is important.

Divide students into 3 groups and assign each a different option to advocate: let nature run its course; start a captive breeding program; or use genetic rescue. Allow groups 5-10 minutes to brainstorm the pros and cons of their arguments and fill out questions 1 & 2 on the worksheet.

Groups observe what others worked on and finish by returning to their own group and finishing the worksheet based on what they learned.

Write or type the pros & cons on three large charts for each scenario based on the students' input. Once all three options have been discussed, each student gets to vote on a course of action. Ask students to provide evidence and reasoning to support their choice.

Ask them to provide evidence and reasoning to support their choice.

They are then asked to fill out a concept map to demonstrate understanding of the Extinction Vortex. The slides then walk through a discussion of the logic behind the correct concept map.

Encourage a group to share their answer and the process for figuring it out. Walk through the logic as a class.

Students are asked to study a table of organisms to determine which would be good and which would be bad models to use in studies of genetic rescue.

Tortoises are the only bad option listed, as they have a slow generation time and are not common. The other species are all actual models for genetic rescue research.

They then switch papers with a partner. They should underline a point they strongly agree with, circle a point they disagree with or think should be explained better, and discuss. Then revise based on the feedback. Students can then share positive/helpful feedback they received.

Specifically, we expect that if genetic rescue is successful:

1. genetic variation should increase and
2. as a result population size should increase (because of higher survival and reproduction)

They are asked to label graphs from Florida panthers and guppies by carefully studying part of the data table used to generate them.

Given the evidence from Florida panther recovery and the study in Trinidadian guppies, should we conduct a second genetic rescue attempt in the panthers?