7.5 Lesson 11 Handout Self-Assessment for Classroom

11.A Develop a system model for a palm farm to explain why both snake (predator) and rat (prey) populations are increasing at the same time.

11.A Develop a system model for a palm farm to explain why both snake (predator) and rat (prey) populations are increasing at the same time.

See the Key Ideas above.

In lessons 9 and 10, students explained the effect of a change in 1 resource on a change in 1 population. This lesson has students extend their understanding to explain changes in multiple populations, and in the context of predators and prey, which goes counter to the initial ideas. If students struggle to conclude that in a system where there are essentially unlimited resources, both predators and prey populations can increase at the same time, consider breaking apart the explanation into 3 chunks: (1) first explain changes to oil palm and how that relates to the rat population, (2) then connect oil palm to the pig population, and (3) then ask students to identify the main food resources for the snake population, and connect the change in those resources to the change in the snake population.

Conclude the discussion by prompting students to think about why these populations are exploding in the oil palm system and not the tropical rainforest. Keep slide E displayed.

Suggested prompt

Sample student response

Why do we think these populations don’t increase like this in their natural rainforest habitat?

• There is not enough food.
• There is more competition for food.
• It’s harder to find food.
• Maybe there are more predators in the rainforest.
• Say, Let’s check our thinking in the next class to see how these populations interact in their natural ecosystem.
• Make sure to save time at the end of this class period to engage students in self-assessment of their participation during small-group and whole-group discussion.