Unit 8: Ecology
Biology · Unit 8 · Paper 3

Ecology unit test

A test on this unit alone, marked as a percentage and a letter grade — for the test your class is actually sitting, rather than for May. Answer everything, then submit once: seeing the answer to question 3 before attempting question 4 makes the final percentage meaningless.

Paper 1Paper 2Paper 3
Each paper is built from this unit’s 42 terms and is the same for everyone, so a teacher can assign “Unit 8, Paper 3” and every student sits the identical test. Multiple choice is marked objectively; the written sections you mark yourself against the model answer and rubric.
Suggested time 31 min 28 points0/17 attempted
1

Ten percent rule

2

Species richness vs evenness

3

Symbiosis types

4

Simpson's diversity index

5

Nitrogen fixation

6

Ecosystem services

7

Biodiversity and stability

8

Population growth rate

9

Fundamental vs realized niche

10

Mimicry

11

Trophic levels

12

Carbon cycle

Short answer 1. Define or explain: Limiting nutrient

3 pts

Short answer 2. Define or explain: Gross vs net primary productivity

3 pts

Short answer 3. Define or explain: Eutrophication

3 pts

Short answer 4. Define or explain: Primary vs secondary consumers

3 pts

Free response

4 pts

A wetland receives runoff from farmland treated with nitrogen fertilizer. Over several years, ecologists record a large increase in algal growth followed by a decline in fish populations and the appearance of an oxygen-depleted zone near the sediment.

(a) Identify the process by which nutrient enrichment leads to the changes described.

(b) Explain how an increase in algal growth causes the oxygen depletion observed near the sediment.

(c) Explain why nitrogen is often a limiting nutrient in aquatic ecosystems despite nitrogen gas making up most of the atmosphere.

(d) Describe one change in farming practice that would reduce the effect described, and explain how it would work.