EnviroIQ · AP Environmental Science · Mock Exam 1
EnviroIQ · AP Environmental Science

EnviroIQ Mock Exam 1 (Mid-Course Diagnostic)

AP Environmental Science · Units 1–5 emphasis (light Unit 6 preview)

Format note (judgment call): This is a half-length diagnostic modeled on the AP APES format at reduced scale, to be taken after Lesson 18. Full-length simulation is Mock Exam 2.

SECTION I — Multiple Choice (40 questions, 45 minutes)

Questions 1–3 refer to the following energy pyramid (kcal/m²/yr): Producers 20,000 → Primary consumers 2,000 → Secondary consumers 200 → Tertiary consumers 20.

Question 1
What ecological rule does this pyramid illustrate?
Question 2
If the producers' value represents net primary productivity, what does NPP equal?
Question 3
To support 40 kcal/m²/yr of tertiary consumers instead of 20, producers would need approximately:
Question 4
Which process removes carbon dioxide from the atmosphere?
Question 5
The phosphorus cycle differs from the nitrogen cycle in that phosphorus lacks a significant:
Question 6
Nitrogen-fixing bacteria convert:
Question 7
Which biome has the highest net primary productivity per unit area?
Question 8
The most fertile soils for large-scale grain agriculture are found in:
Question 9
An estuary is more productive than the open ocean primarily because it has:
Question 10
Species diversity depends on both species richness and:
Question 11
A sea otter that controls urchin populations and maintains a kelp forest is a(n):
Question 12
The single greatest threat to global biodiversity is:
Question 13
Primary succession differs from secondary succession because it:
Question 14
Typical pioneer species in primary succession are:
Question 15
According to island biogeography, which island holds the most species?
Question 16
On a tolerance curve, the range where a population thrives is the:
Question 17
A specialist species with a narrow tolerance range is most vulnerable to:
Question 18
A J-shaped population curve indicates:
Question 19
A population of 4,000 has 400 births and 200 deaths in a year. Its growth rate is:
Question 20
A population grows at 3.5% per year. Its doubling time is about:
Question 21
Which is a density-dependent limiting factor?
Question 22
A Type III survivorship curve is characterized by:
Question 23
In the demographic transition model, the stage with the fastest population growth is:
Question 24
A wide-based (triangular) age-structure diagram predicts:
Question 25
Replacement-level total fertility rate is approximately:
Question 26
The strongest earthquakes and most tsunamis occur at:
Question 27
Marble forms from limestone through:
Question 28
The fertile topsoil layer where most roots grow is the:
Question 29
Which soil has the highest permeability and lowest water-holding capacity?
Question 30
The ozone layer that protects life from UV radiation is located in the:
Question 31
Major deserts near 30° latitude form because air there is:
Question 32
Earth's seasons are caused primarily by:
Question 33
During an El Niño year, upwelling off the coast of South America is:
Question 34
The tragedy of the commons occurs when a resource is:
Question 35
The most water-efficient irrigation method is:
Question 36
Salinization of farmland results from:
Question 37
Contour plowing reduces soil erosion by:
Question 38
Rotating a cereal crop with a legume improves soil by:
Question 39
Acid mine drainage forms when:
Question 40
(Unit 6 preview) Which energy source is nonrenewable but emits no CO₂ during operation?

SECTION II — Free Response (2 questions, 35 minutes)

Question 1 — Designing an Investigation (10 points)

Farmers near a lake apply nitrogen and phosphorus fertilizer. The lake now experiences summer algal blooms and fish kills. A student hypothesizes that phosphorus runoff is the main driver of algal growth in the lake.

(a) Identify the independent and dependent variables for an experiment testing this hypothesis. (2 pts) (b) Describe a controlled experiment using lake-water samples to test whether phosphorus drives algal growth. Include a control group. (3 pts) (c) Identify one variable that must be held constant and explain why. (2 pts) (d) A water sample shows GPP = 2,800 mg O₂/L/day and respiration = 1,000 mg O₂/L/day. Calculate NPP. Show work. (1 pt) (e) Explain the sequence by which excess phosphorus leads to a fish kill. (2 pts)

Question 2 — Analyze an Environmental Problem and Propose a Solution (10 points)

A region of sloped farmland practices intensive tillage and continuous monoculture. It suffers severe soil erosion, declining fertility, and nutrient runoff into a river. Nearby, a shared aquifer used by hundreds of farms is being depleted because each farm pumps freely.

(a) Explain how intensive tillage on slopes increases erosion. (2 pts) (b) Explain how the aquifer situation illustrates the tragedy of the commons. (3 pts) (c) Propose two sustainable agriculture practices to reduce erosion and nutrient runoff, and explain the mechanism of each. (4 pts) (d) Propose one solution to the aquifer depletion and justify it. (1 pt)

Show answer key & explanations

ANSWER KEY — Section I

  1. (B) 10% rule — each level ~10% of the one below.
  2. (C) NPP = GPP − respiration.
  3. (D) Doubling the top requires doubling the base: 40,000 kcal.
  4. (C) Photosynthesis. (A)/(B)/(D) release CO₂.
  5. (B) Atmospheric (gaseous) phase.
  6. (B) Atmospheric N₂ → ammonia.
  7. (D) Tropical rainforest.
  8. (A) Temperate grasslands.
  9. (B) Continuous nutrient input + shallow sunlit water.
  10. (B) Evenness.
  11. (D) Keystone species.
  12. (A) Habitat destruction.
  13. (C) Begins where there is no soil.
  14. (B) Lichens and mosses.
  15. (D) Large and near.
  16. (A) Optimal range.
  17. (C) Environmental change.
  18. (B) Exponential growth.
  19. (C) (400−200)/4,000 = 5%.
  20. (A) 70/3.5 = 20 years.
  21. (C) Competition for food.
  22. (D) Very high juvenile mortality.
  23. (B) Stage 2.
  24. (A) Rapid population growth.
  25. (C) 2.1.
  26. (D) Convergent (subduction) boundaries.
  27. (B) Heat and pressure (metamorphism).
  28. (A) A horizon.
  29. (C) Sandy.
  30. (D) Stratosphere.
  31. (B) Sinking and warming/drying.
  32. (A) Earth's 23.5° axial tilt.
  33. (C) Suppressed.
  34. (D) Shared and overused; costs collective.
  35. (C) Drip.
  36. (A) Salt accumulation as irrigation water evaporates.
  37. (C) Plowing across a slope's contours to slow runoff.
  38. (D) Adding nitrogen via nitrogen-fixing bacteria.
  39. (B) Exposed sulfide minerals + air + water → sulfuric acid.
  40. (A) Nuclear.

Answer distribution (A/B/C/D): A = 9, B = 11, C = 10, D = 10 — spread across all four letters (no clustering).

ANSWER KEY — Section II

Question 1 (10 pts)

  • (a) 1 pt IV = phosphorus level added (concentration); 1 pt DV = algal growth (measured as chlorophyll, cell count, or O₂/NPP). (2)
  • (b) 1 pt set up multiple identical water samples with varying added phosphorus; 1 pt include a control with no added phosphorus; 1 pt measure algal growth the same way in all after equal time. (3)
  • (c) 1 pt names a valid constant (light, temperature, nitrogen level, water volume, starting algae); 1 pt explains it prevents a confounding variable (an alternative cause of algal change). (2)
  • (d) 1 pt NPP = 2,800 − 1,000 = 1,800 mg O₂/L/day. (1)
  • (e) 1 pt phosphorus triggers an algal bloom; 1 pt algae die, decomposer bacteria consume oxygen → hypoxia kills fish. (2)

Question 2 (10 pts)

  • (a) 1 pt tillage loosens/exposes bare soil; 1 pt on slopes water runs downhill carrying soil away (erosion). (2)
  • (b) 1 pt aquifer is a shared/open-access resource; 1 pt each farm gains full private benefit from pumping more; 1 pt the cost (falling water table) is shared, so all overuse it. (3)
  • (c) Two practices, each 1 pt name + 1 pt mechanism (contour plowing/terracing → slow runoff; no-till → residue protects soil; cover crops → hold soil + uptake nutrients; crop rotation → fertility + fewer inputs; buffer strips → trap runoff). (4)
  • (d) 1 pt names a valid solution (pumping quotas/permits, water pricing, cooperative management, efficient/drip irrigation) with brief justification tying it to reducing withdrawal below recharge. (1)

⭐ Diagnostic guidance: Score Section I out of 40 and each FRQ out of 10. As a rough calibration, ≥30/40 MC and ≥7/10 per FRQ suggests you're on track for a 4–5 on units 1–5. Review any missed trap pairs (primary vs. secondary succession, N vs. P cycles, density-dependent vs. -independent) before Mock Exam 2.

Content pending external review.

Score summary

Your running multiple-choice score appears in the bar below. Self-score the free-response section with the rubrics in the answer key, then use the diagnostic table to target review.

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