HS-LS2-8: Group Behavior and Survival
Also called NGSS HS-LS2-8 · Topic: Interdependent Relationships in Ecosystems · Life Science
The Official Wording
Evaluate evidence for the role of group behavior on individual and species’ chances to survive and reproduce.
Clarification statement: Emphasis is on: (1) distinguishing between group and individual behavior, (2) identifying evidence supporting the outcomes of group behavior, and (3) developing logical and reasonable arguments based on evidence. Examples of group behaviors could include flocking, schooling, herding, and cooperative behaviors such as hunting, migrating, and swarming.
NGSS Lead States, 2013 · Read it on nextgenscience.org · checked October 15, 2026
What HS-LS2-8 Means in Plain English
Students weigh evidence about why many animals live and act in groups. They separate what one animal does from what the group does together, such as fish schooling, wolves hunting as a pack or birds flocking, and judge how each behavior changes the odds of surviving and reproducing.
The focus is the argument: a strong claim names the behavior, the evidence and the reasoning that links them, and it admits costs like competition for food inside the group. It builds on MS-LS1-4 and connects to how populations hold steady in HS-LS2-6.
HS-LS2-8 I Can Statements
- I can tell an individual behavior apart from a group behavior.
- I can use evidence to argue how a group behavior aids survival.
- I can name a cost that comes with living in a group.
HS-LS2-8 Worked Example
A classroom simulation of the many-eyes effect, with students as feeding animals and a paper hawk as the predator.
Do animals feeding in bigger groups spot a predator sooner, and can each one spend more time feeding?
Set It Up: Cups of mixed dried beans to sort, a paper hawk cutout taped to a meter stick, a measuring tape and a stopwatch.
- Feeders sort beans by color with heads down and may look up whenever they choose, while one student slowly carries the hawk in from the doorway.Group sizes: 1, 3 and 6 feeders
- The first feeder to see the hawk calls out, and the class measures how far away it still was.Alone: 2 m. Group of 3: 4 m. Group of 6: 6 m
- Each feeder also counts the beans they sorted in one minute.Alone: 18 beans. In a group of 6: 27 beans each
- Repeat each group size three times with new feeders and average the results.Same pattern in every round
- List costs too, like feeders bumping elbows over one shared bean cup.Benefit and cost columns
Larger groups spotted the hawk from farther away, and each member sorted more beans because no one had to keep watch alone.
Why it works: With many animals scanning, someone is almost always looking up, so each animal can feed more and still escape in time, which raises its odds of living long enough to reproduce.
Common Mistakes with HS-LS2-8
Treating the group as one animal
“The herd decides to survive”
Try this: Ask what each individual gains or loses by staying in the group, since natural selection acts on individuals and their offspring.
Claims with no evidence
“Schooling helps fish because there are more of them”
Try this: Back each claim with data, like detection distance or capture rate, and explain the reasoning that connects that data to survival.
Ignoring the costs
Only benefits listed in the argument
Try this: Include costs such as sharing food, spreading disease and attracting predators, then weigh whether the benefits still come out ahead.
Where HS-LS2-8 Fits
Practice HS-LS2-8
Quick Check
- Is a fish swimming toward food an individual or a group behavior? What about a school turning together?
- How can living in a herd protect a single zebra?
- Name one cost of living in a group.