Look for: Inclusion of the living components of the sys…

1.A Develop an initial system model to describe a phenomenon in which changes to one living component of an ecosystem (cause) affect the other living parts of the ecosystem (effect).

Inclusion of the living components of the system models (such as the oil palm trees, orangutans, rats, snakes, tigers, and pigs) in the systems model

Inclusion of at least some of the needs that these livings components have in the system model, such as needs for food, water, air, habitat, or shelter

Initial ideas about what causes the population sizes of living things to increase in number (a lot of food or water, a lot of mates, not very many predators) and decrease in number (very little food or water, can’t reproduce, many predators)

Uncertainty about interactions between the living things within the system and the specific cause-and-effect relationships in the system model

Uncertainty about which components of the system model are causing increases or decreases in the different population sizes

If your students struggle with identifying important components of the ecosystems, refer them back to the class-developed list of ecosystem components. Students may also wish to revisit Growing Oil Palm in Indonesia to find more information about the components in the ecosystem. If students are not sharing their initial ideas about what causes the population sizes of living things to increase or decrease in number, or if students are not sharing their uncertainty about interactions in the system model, encourage them to draw a large question mark and then record their thinking. It may help to refer to these thoughts as “first draft thinking,” “initial ideas,” or “questions I have.” It can also help to provide students with the sentence starter “Maybe…” and then ask them to record their thinking.

This assessment guidance also applies for the Consensus Discussion that follows.

A range of student-created initial models are shown below: