How do human activities affect ecosystems, and how can we reduce the damage?
Evaluate the impact of human activities on ecosystems (habitat destruction, pollution, invasive species, climate change) and design solutions to reduce that impact (GSE SB5.c, SB5.e).
A Georgia Milestones Biology EOC answer on human impact: habitat destruction, pollution, invasive species, and climate change, their effects on biodiversity and ecosystem stability, and conservation solutions to reduce the impact.
Reviewed by: AI editorial process; not yet individually human-reviewed
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What this topic is asking
Standards SB5.c and SB5.e ask you to evaluate human impacts on ecosystems and to design solutions to reduce them. For the Georgia Milestones Biology EOC you must know the major human impacts (habitat destruction, pollution, invasive species, climate change), explain how each harms biodiversity and stability, and propose conservation solutions. Because SB5 is the largest domain, these applied items carry real weight, and they often ask you to trace a chain of effects and suggest a fix.
The major human impacts
Know each impact and how it harms ecosystems:
- Habitat destruction. Clearing land for farming, logging, and cities removes the habitat organisms need, which is a leading cause of declining biodiversity and extinction.
- Pollution. Chemicals, plastics, and excess nutrients (fertilizer runoff) damage organisms and degrade water and air. Excess fertilizer causes algal blooms that deplete oxygen and kill aquatic life.
- Invasive species. Non-native species introduced (often by humans) can spread rapidly because they have no natural predators in the new ecosystem, outcompeting or preying on native species and lowering biodiversity.
- Climate change. Greenhouse gas emissions (from burning fossil fuels) raise global temperatures and shift climates faster than many species can adapt, altering habitats, ranges, and timing.
Why these reduce stability
Each impact tends to reduce biodiversity, and lower biodiversity makes an ecosystem less stable (the link to the biodiversity topic). Removing or stressing species breaks food-web links, so the effects can cascade. A diverse, intact ecosystem can absorb some disturbance; a degraded one is more fragile.
Conservation solutions
Try this
Q1. State why an invasive species can spread rapidly and harm native species. [2 points]
- Cue. It is non-native and often has no natural predators in the new ecosystem, so it spreads and outcompetes or preys on native species, lowering biodiversity.
Q2. Propose one solution to reduce the impact of fertilizer runoff on a river. [1 point]
- Cue. Use less fertilizer, plant buffer strips of vegetation along the bank to absorb runoff, or improve farming practices to keep nutrients on the field.
Exam-style practice questions
Practice questions written in the style of GaDOE exam questions on this dot point, with worked answer explainers. The year tag is the paper they imitate, not the source.
Milestones (style)1 marksA non-native species is introduced to an ecosystem, spreads rapidly, and outcompetes native species. This is an example of: (A) a keystone species (B) an invasive species (C) a pioneer species (D) mutualismShow worked answer →
A 1-point selected-response item on invasive species.
The correct answer is B. An invasive species is a non-native organism that spreads rapidly in a new ecosystem, often because it has no natural predators there, and outcompetes or preys on native species, reducing biodiversity. A keystone species (A) is a native species with a large role, a pioneer species (C) colonizes bare ground in succession, and mutualism (D) is a relationship where both partners benefit. The rapid spread and harm to natives identify an invasive species.
Milestones (style)2 marksA river is polluted by runoff from farms (excess fertilizer), causing algae to grow rapidly and fish to die. Explain the chain of effects and propose one solution to reduce the impact.Show worked answer →
A 2-point item evaluating an impact and designing a solution.
Excess fertilizer in the runoff adds nutrients to the river, causing a rapid overgrowth of algae (an algal bloom). When the algae die, decomposers use up the oxygen in the water breaking them down, so oxygen levels drop and the fish die from lack of oxygen. One reasonable solution is to reduce fertilizer runoff, for example by using less fertilizer, planting buffer strips of vegetation along the riverbank to absorb runoff, or improving farming practices to keep nutrients on the field. Full points need the nutrient-to-algae-to-low-oxygen chain and a valid solution that reduces the runoff.
Related dot points
- Evaluate the factors that affect biodiversity and the stability of ecosystems, including keystone species, the effects of removing species, and symbiotic relationships (GSE SB5.c).
A Georgia Milestones Biology EOC answer on biodiversity and stability: why diverse ecosystems are more stable, the role of keystone species, the effects of removing a species, and the three types of symbiosis (mutualism, commensalism, parasitism).
- Predict the impact of environmental change on the stability of an ecosystem, including ecological succession (primary and secondary) and the effects of natural and human-induced disturbances (GSE SB5.d).
A Georgia Milestones Biology EOC answer on environmental change: ecological succession (primary versus secondary), pioneer and climax communities, and how natural and human-induced disturbances affect the stability of an ecosystem.
- Analyze data on population growth, including exponential and logistic growth, carrying capacity, and limiting factors (density-dependent and density-independent) (GSE SB5.a).
A Georgia Milestones Biology EOC answer on population growth: exponential versus logistic growth, carrying capacity, density-dependent and density-independent limiting factors, and how to read a population growth curve.
- Analyze the cycling of matter through ecosystems, including the carbon, nitrogen, and water cycles, and the roles of photosynthesis, respiration, and decomposers (GSE SB5.b).
A Georgia Milestones Biology EOC answer on the cycling of matter: the carbon cycle (photosynthesis and respiration), the nitrogen cycle (fixation by bacteria), and the water cycle, and how decomposers recycle nutrients, contrasted with the one-way flow of energy.
- Analyze the flow of energy through ecosystems using food chains, food webs, and energy pyramids, including the roles of producers, consumers, and decomposers and the ten percent rule (GSE SB5.b).
A Georgia Milestones Biology EOC answer on energy flow: producers, consumers, and decomposers, trophic levels, food chains and food webs, the ten percent rule, and why energy pyramids narrow toward the top.
Sources & how we know this
- Biology Georgia Standards of Excellence (GSE) — Georgia Department of Education (2024)
- Georgia Milestones Biology EOC Assessment Guide — Georgia Department of Education (2024)