Milestones 7 & 8

Human Impact & Group Behavior

Level 2 Review | Week 8 | Environmental Science SP26

What Level 2 Means

Level 1

Identifies what is happening

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“Lumbering is a threat to the marbled murrelet.”

“Murrelets nest in pairs.”

→

Level 2

Explains mechanism + significance

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“Lumbering removes old-growth nesting platforms; murrelets can’t adapt to managed forests, so reproductive success drops sharply. This is a major range-wide threat.”

M7: Human Impacts — Foundational Concepts

What counts as a human impact?

• Land use change (development, agriculture, logging)
• Pollution (chemical, noise, light)
• Resource extraction (water diversion, overharvesting)
• Introduced species
• Climate-driven shifts (altered timing, temperature, precipitation)

Direct vs. indirect impacts

• Direct: immediately affects the species (hunting, trapping, road mortality)
• ​
• Indirect: changes the environment the species depends on (habitat loss, prey decline, disease spread by invasives)

How ecologists evaluate impact

• Specificity: what exactly changes?
• Pathway: how does the change reach the species?
• Scale: local patch vs. range-wide
• Severity: reproductive failure, survival decline, or habitat loss?
• Reversibility: can it recover if the pressure stops?

M8: Group Behavior — Foundational Concepts

Behavior types: flocking • herding • schooling • colonial nesting • cooperative hunting • parental care • pair bonding • mate guarding • lek displays • seasonal aggregation • territorial defense • migration

Why do group behaviors exist?

Natural selection favors behaviors that increase survival or reproduction. Group behaviors persist because they:

• Reduce predation risk (dilution, vigilance)
• Improve foraging efficiency
• Increase reproductive success
• Improve offspring survival

Solitary species

Most solitary species still have important reproductive behaviors:

• Mate-finding (calling, pheromones, display)
• Mate guarding or pair bonding
• Territorial defense to secure breeding sites
• Parental care

Use one of these if your species doesn’t aggregate.

Why behavior matters for conservation

Behaviors evolved for stable conditions. When habitat is fragmented or populations drop:

• Groups can’t form (schooling fish, colonial nesters)
• Mates can’t find each other (Allee effect)
• Learned behaviors disappear from populations
• Reproductive timing gets disrupted

Level 2 Thinking Questions

Use these to test whether you understand the relationships, not just the facts.

Relationship

How does [specific human activity] change the conditions your SSC depends on — and what happens to the population as a result?

Circumstance

If the human impact continued at its current rate for 20 years, what would you predict for your species’ population? What’s your reasoning?

Comparison

How does the significance of this impact compare to other threats your species faces?

Relationship

How does the group or reproductive behavior directly increase survival or reproduction? What would change if it were disrupted?

Credibility

What evidence supports your claims about the impact or the behavior? Where does it come from?

Milestone 7: Human Impact

I can design, evaluate, and refine a solution for reducing human impacts on the environment and biodiversity.

Mechanism

How does the human activity cause harm?

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Trace the chain: activity → environmental change → effect on species.

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Consider: habitat, food supply, reproduction, disease, competition, climate.

Significance

How serious is the impact?

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Is it local or range-wide? Does it hit reproduction, survival, or habitat? Is recovery possible?

​

A strong answer characterizes the scale, not just the existence, of the threat.

Milestone 8: Group Behavior

I can evaluate the evidence for the role of group behavior on individual and species’ chances to survive and reproduce.

Solitary species: use a reproductive behavior (pair bonding, territorial display, parental care) if your species doesn’t aggregate.

Function

Why does this behavior exist?

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Does it reduce predation risk? Increase access to mates? Improve offspring survival? Secure territory?

Significance

How important is this behavior to the population?

​

What would happen if habitat loss, human activity, or population decline disrupted it?

Connecting M7 + M8: The Deeper Question

Option B for both milestones asks you to connect human impact directly to behavior disruption.

Human Activity

(M7)

→

Environmental Change

(mechanism)

→

Behavior Disrupted

(M8 connection)

→

Population Effect

(significance)

Example: Urban development fragments forest → removes old-growth nest trees → disrupts the pair bonding + territory-holding that spotted owls rely on → breeding pairs can’t re-establish, recruitment drops.

This Week: Presentations & Print Deadline

Mon–Wed

Content + Printing

• Work on M7 & M8 required tasks + choose-one options
• Carve and print remaining color layers

Thursday

Presentations

• M7: human impact — mechanism + significance
• M8: behavior — function + importance
• Show your block print; describe your SSC and associated species

Friday

Open Work Time

• Finish any remaining printing
• Revise past milestone presentations (M1–M6) before Cycle 2 closes

📌 Print due Friday — Hang your print in the room for me to assess that afternoon. If it’s not up, it won’t be graded.

The Core of This Week

Level 2 = Mechanism + Significance

M7

Don’t stop at naming the threat. Explain how it works and how serious it is.

M8

Don’t stop at naming the behavior. Explain what it does for the population and what depends on it.

Option B

Connects both: human impact → behavior disrupted → population consequence.

Environmental Science SP26 | Week 8 | Milestones 7 & 8