Kelp forests are highly productive marine ecosystems found in cold, nutrient-rich coastal waters. These underwater forests support diverse food webs, with kelp as the primary producer converting solar energy into chemical energy through photosynthesis. Sea urchins are primary consumers that graze on kelp, while sea otters are secondary consumers that prey on sea urchins.
A.
Describe one way that energy is lost as it flows from kelp to sea urchins in this food chain.
B.
Explain how the increase in sea urchin population density could affect the amount of solar energy captured by the kelp forest ecosystem.
Figure 1. Kelp biomass and sea urchin density
C.
Based on the data in Figure 1, identify the kelp biomass in May.
Figure 2. Dissolved nitrate in kelp forest water
D.
Based on the data in Figure 2, describe the trend in dissolved nitrate concentration from January to June.
E.
Scientists hypothesized that seasonal upwelling patterns control nutrient availability in kelp forests. Describe one way that the data in Figure 2 support this hypothesis.
Treatment
Nitrate added (mg/L)
Phosphate added (mg/L)
Algae density after 7 days (cells/mL)
Control (lake water only)
0
0
2,400
Lake water + nitrate
10
0
8,900
Lake water + phosphate
0
5
9,200
Lake water + nitrate + phosphate
10
5
24,600
F.
Nutrient pollution from agricultural runoff can impact aquatic ecosystems. A group of students investigated how nitrogen and phosphorus from fertilizers affect algae growth in freshwater lakes. They collected water from a local lake and divided it into four treatment groups. The students added different combinations of nitrate and phosphate to the water samples, then measured algae density after 7 days. All samples were kept at the same temperature and light conditions.
i.
Identify the independent variable in the students' investigation.
ii.
Identify the dependent variable in the students' investigation.
G.
The data from the student investigation are shown in the following table.
i.
Explain why the students included a control treatment with no added nutrients in their experimental design.
ii.
Explain how the results would differ if students had conducted the experiment in water with very low dissolved oxygen levels rather than well-oxygenated lake water.
H.
Describe one effect that increasing ocean temperature could have on the kelp forest ecosystem described in the passage. Climate change is causing ocean temperatures to rise in many coastal regions where kelp forests exist.
What the Investigation Design FRQ asks
This is FRQ 1 on the AP Environmental Science exam. You get an environmental scenario with data or figures, analyze what the data show, and work through an investigation: its variables, its results, and what they mean.
Describe how the data support a hypothesis or claim
1 pt
F
Part F: Investigation
Identify the investigation’s question or hypothesis and its independent variable
2 pts
G
Part G: Results
Explain the investigation’s results and what could change them
2 pts
H
Part H: Connection
Describe a related environmental effect
1 pt
How Investigation Design FRQ practice works
Each question follows the exam’s format, from the full prompt to a score on every part.
1
Read the full question
The scenario, the figures, and every part, laid out the way the exam shows them.
2
Write on a 23-minute timer
The time to plan for on exam day. Pause it or turn it off, and your response saves as you go.
3
Submit for a score out of 10
Your response is scored against the scoring guidelines written for that question. Your first score is included.
Feedback on every part
A summary at the top tells you what to work on next. Below it, each part shows whether you earned the point and what the scoring guidelines were looking for.
The student correctly identifies approximately 1,400 breeding pairs in 1995, which matches the acceptable response. Full credit earned.
Part B: 0/1 point
The student incorrectly states that the number of breeding pairs 'generally increased' from 1995 to 2008. The correct trend is an overall decrease (with fluctuations). This directly contradicts the data shown in the graph. No credit earned.
Part C: 1/1 point
The student correctly explains that as sea level rose, the number of breeding pairs decreased, demonstrating a negative relationship that refutes the hypothesis of a population increase. Full credit earned.
Detailed feedback on a practice Investigation Design FRQ
Questions about the Investigation Design FRQ
How many responses can I get scored?
You can read every question without a plan. Your first scored response is included. A plan unlocks unlimited scoring.
What does the investigation part ask?
On most questions, parts F and G describe an investigation. You identify its question or hypothesis and its independent variable, then explain its results.
How specific should my variables be?
Name what is measured and how, with units. “Dissolved oxygen in mg/L” earns more than “water quality.”
How is FRQ 1 different from FRQ 2?
FRQ 1 centers on an investigation: its hypothesis, variables, and results. FRQ 2 asks you to interpret quantitative data, then propose and justify a solution.
Are these real College Board questions?
No. We wrote them in the AP format, with the same parts, and wrote scoring guidelines for each one.
More AP Environmental Science practice
Data Analysis FRQ practice
Quantitative data questions with the scenario, the data, and all ten parts.
