What are the big human pressures driving species loss, and why does losing biodiversity matter?
Topic 9.10 Human Impacts on Biodiversity: identify the major human causes of biodiversity loss (HIPPCO) and explain why declining biodiversity matters.
A focused answer to APES Topic 9.10, covering the HIPPCO causes of biodiversity loss, why habitat loss is the largest, the importance of biodiversity for ecosystem services and resilience, the sixth mass extinction, and conservation responses, with a worked species-loss reasoning example.
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What this topic is asking
The College Board (Topic 9.10) wants you to identify the major human causes of biodiversity loss and explain why declining biodiversity matters.
The HIPPCO causes
Population growth underlies many of the others, increasing demand for land, resources and energy; climate change shifts conditions faster than many species can adapt; and overharvesting depletes populations directly.
Why biodiversity matters
A sixth mass extinction
Why this matters
Topic 9.10 is the capstone of the entire course, pulling together the threats from across all nine units, energy and land use, pollution, invasive and endangered species, and climate change, into a single framework. It connects back to biodiversity and ecosystem services (Unit 2) and is among the most heavily tested ideas on the AP exam.
Try this
Q1. Identify the single largest cause of biodiversity loss. [1 point]
- Cue. Habitat destruction (and fragmentation).
Q2. Explain why declining biodiversity reduces ecosystem resilience. [2 points]
- Cue. More diverse ecosystems have more species that can fill ecological roles and respond to change, so losing species leaves fewer able to maintain functions and recover from disturbance, weakening resilience.
Exam-style practice questions
Practice questions written in the style of College Board exam questions on this dot point, with worked answer explainers. The year tag is the paper they imitate, not the source.
AP 2022 (style)4 marksSection II (FRQ). (a) Identify the human activity that is the single largest cause of biodiversity loss. (b) List the other major human causes of biodiversity loss. (c) Explain why declining biodiversity reduces ecosystem resilience. (d) Describe one strategy to conserve biodiversity.Show worked answer →
A 4-point FRQ on human impacts on biodiversity.
(a) Identify (1 point): habitat destruction (and fragmentation), the largest cause.
(b) List (1 point): the rest of HIPPCO: invasive species, population growth, pollution, climate change, and overharvesting.
(c) Explain (1 point): more diverse ecosystems are more resilient because different species can fill roles and respond to change, so losing species weakens the ecosystem's ability to recover from disturbance.
(d) Describe (1 point): protected areas, habitat restoration, laws and treaties, sustainable resource use, or controlling invasive species.
Markers reward habitat destruction as the largest cause, the rest of the HIPPCO list, the diversity-supports-resilience explanation, and a valid conservation strategy.
AP 2018 (style)1 marksSection I (multiple choice). According to the HIPPCO framework, the single greatest cause of biodiversity loss is: (A) overharvesting (B) habitat destruction and fragmentation (C) pollution (D) invasive species. Justify your choice.Show worked answer →
A 1-point MCQ on biodiversity loss. The answer is (B).
In the HIPPCO framework, habitat destruction and fragmentation is the single greatest cause of biodiversity loss, as clearing and dividing habitat removes the places species need to live. Overharvesting (A), pollution (C) and invasive species (D) are all major causes too, but habitat loss leads. The trap is choosing another real threat; all are in HIPPCO, but habitat destruction is the largest.
Related dot points
- Topic 9.9 Endangered Species: explain the factors that make species vulnerable to extinction and describe how endangered species are protected.
A focused answer to APES Topic 9.9, covering what makes a species endangered, the traits that increase extinction risk, the human causes, conservation strategies (protected areas, captive breeding, the Endangered Species Act, CITES), and keystone species, with a worked minimum-viable-population example.
- Topic 9.8 Invasive Species: explain what makes a species invasive and describe the impacts of invasive species and how they are managed.
A focused answer to APES Topic 9.8, covering what makes a species invasive, how they are introduced, why the lack of natural predators lets them spread, their impacts on native species and ecosystems, the link to climate change, and methods of control, with a worked exponential-spread reasoning example.
- Topic 2.1 Introduction to Biodiversity: describe the three levels of biodiversity and explain how genetic and species diversity contribute to ecosystem resilience.
A focused answer to APES Topic 2.1, covering genetic, species and habitat diversity, species richness and evenness, the value of genetic diversity, bottlenecks and resilience, with a worked diversity-comparison question.
- Topic 2.2 Ecosystem Services: describe the four categories of ecosystem services and explain how the disruption of ecosystems affects the services they provide.
A focused answer to APES Topic 2.2, covering provisioning, regulating, cultural and supporting ecosystem services, examples of each, their economic value, and how disruption reduces them, with a worked valuation question.
- Topic 9.5 Global Climate Change: describe the evidence and effects of global climate change and explain the role of positive feedback loops.
A focused answer to APES Topic 9.5, covering the evidence for global climate change, its effects (rising temperatures, melting ice, sea-level rise, extreme weather, shifting species), positive feedback loops (ice-albedo, permafrost methane, water vapor), the difference between weather and climate, and mitigation and adaptation, with a worked sea-level reasoning example.
Sources & how we know this
- AP Environmental Science Course and Exam Description — College Board (2020)