Look for: There is a two-way relationship between orang…

12.A Gather information from text, images, and data tables to clarify claims that a change in the orangutan population could affect fruit trees because there is a mutually beneficial relationship between the two.

See the Key Ideas above, plus the following:

There is a two-way relationship between orangutans and fruit trees: orangutans get food, and fruit trees get their seeds spread throughout the tropical rainforest.

If students struggle to understand that fruit tree populations depend on orangutans, add a deeper discussion about how plant populations may increase or decrease over time. First, elicit from students their prior knowledge and experiences of plants that could be useful to their thinking. To do this, ask the following probing questions: Have you ever noticed a young plant growing in a new area? How did it get there? Have you ever noticed some plants, like dandelions, becoming more and more prevalent, year after year? How does that happen? How does a plant population in our community (for example, dandelions, sticker burrs, or grass) get larger or smaller over time? If seeds from a large plant, like a tree, drop on the ground below the tree, why might those seeds grow or not grow into adult plants? Once students more fully understand that plant populations increase by seed dispersal away from parent plants, have students then connect back to why fruit tree populations in the tropical rainforest would be dependent on the orangutans to spread their seeds.

Brainstorm related phenomena and cases we know about (optional). If time permits and/or you choose to add the extension opportunity below, ask your students to brainstorm other mutually beneficial seed dispersal relationships they know about or have seen or heard about. Keep a list charted on the class whiteboard or chart paper for use in the extension opportunity.