Students who demonstrate understanding can: Construct an explanation that predicts patterns of interactions among organisms across multiple ecosystems.
Clarification statement: Emphasis is on predicting consistent patterns of interactions in different ecosystems in terms of the relationships among and between organisms and abiotic components of ecosystems. Examples of types of interactions could include competitive, predatory, and mutually beneficial.
Official wording from the Next Generation Science Standards (NGSS Lead States, 2013). NGSS is a registered trademark of WestEd. Neither WestEd nor the lead states and partners that developed the NGSS were involved in the production of this page, and they do not endorse it. View on nextgenscience.org
Coral reefs, deserts, rainforests and grasslands look nothing alike, yet the same kinds of relationships between organisms appear in each of them. Predators hunt prey. Organisms compete for the same limited food, water or space. Some pairs of species help each other, such as bees and flowers, or clownfish and sea anemones. Because these patterns repeat, scientists can predict how organisms in an unfamiliar ecosystem are likely to interact.
Students construct explanations that name the type of interaction, describe how each organism is affected, and predict what would happen if one partner changed in number. For instance, if two bird species eat the same seeds, a drop in seeds should hurt both, and the stronger competitor may push the other out. In a mutualism, losing one partner harms the other.
The emphasis is on patterns across many ecosystems, so good tasks ask students to compare an example from one ecosystem with a matching example from a very different one.
Most competition is indirect: two species simply use the same limited resource, so there is less left for the other. They may never meet face to face.
Predators help keep prey populations in check, which can protect plants and other species. Removing predators often causes problems.
Mutualism, in which both species benefit, is common. Pollination and the partnership between cleaner fish and larger fish are examples.
In an African savanna, oxpecker birds eat ticks off zebras. On a coral reef, cleaner wrasse fish eat parasites off larger fish. Identify the pattern and predict what happens if the cleaners disappear.
Answer: Both are mutually beneficial interactions; losing the cleaner species would let parasites build up, harming the host animals in each ecosystem.
Give students a set of interaction cards from at least four ecosystems and ask them to sort by pattern rather than by habitat. Then challenge them to predict an interaction in an ecosystem they have not studied, using only the pattern.
Assessment often presents a short scenario and asks students to classify the interaction and predict effects, so practice 'if ... then ... because' prediction sentences.
Original questions written for this standard. Choose an option or type your answer, then press Check. Every question has a worked explanation.
Answer: B) Mutualism
Both benefit: the bee gets food and the flower gets pollinated.
Answer: C) Competition
They use the same limited food resource, so they compete.
Answer: predator (also accepted: a predator, the predator)
A predator hunts and eats prey.
Answer: A) It gets less light and may grow less
The taller plant shades the shorter one, outcompeting it for light.
Answer: B) The prey population increases
With fewer animals hunting them, more prey survive and reproduce, at least until food runs short.
Answer: mutualism (also accepted: mutualistic, mutualistic relationship)
Mutualism benefits both partners.
Develop a simple model that mimics the function of an animal in dispersing seeds or pollinating plants.
Evaluate evidence for the role of group behavior on individual and species' chances to survive and reproduce.
A full lesson with slides, activities and an exit ticket on patterns of interaction in ecosystems, pitched to grades 6-8 and editable in PowerPoint or Google Slides.
Make a lesson βA printable, differentiated worksheet on MS-LS2-2 with an answer key, ready in about a minute.
Make a worksheet βTurn patterns of interaction in ecosystems into a quiz students answer online that marks itself, with a class summary for you.
Build a test βThe clarification statement gives competitive, predatory and mutually beneficial interactions as examples.
Because the goal is to recognize consistent patterns that let students predict interactions anywhere, not just describe one habitat.