Unit 1: The Living World: Ecosystems
Env. Science · Unit 1 · Paper 3

The Living World: Ecosystems 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 19 terms and is the same for everyone, so a teacher can assign “Unit 1, 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 37 min 34 points0/17 attempted
1

Ecosystem

2

Terrestrial biomes

3

Aquatic biomes

4

Nitrogen fixation

5

Hydrologic cycle

6

Ecosystem services

7

Phosphorus cycle

8

Trophic levels and the 10% rule

9

Nitrification and denitrification

10

Energy transfer calculation

11

Food chain vs food web

12

Why food chains are short

Short answer 1. Define or explain: Biomass pyramid inversions

3 pts

Short answer 2. Define or explain: Carbon cycle reservoirs

3 pts

Short answer 3. Define or explain: Calculating net primary productivity

3 pts

Short answer 4. Define or explain: Net primary productivity units

3 pts

Free response

10 pts

This course has no free-response prompt tagged to this unit, so one from elsewhere in the course is used. It is still worth writing — the skill transfers.

Country Z has a population of 40 million, a crude birth rate of 34 per 1,000, a crude death rate of 9 per 1,000, and net migration of approximately zero.

Calculate the population growth rate as a decimal.

Express that growth rate as a percentage per year.

Calculate the doubling time using the rule of 70.

Show the calculation for the number of people added in the first year.

State the number of people added in the first year.

Identify the phenomenon that keeps this population growing after fertility falls to replacement level.

Explain the age-structure reason that phenomenon occurs.

Explain what this means for the total number of births over the coming decades.

Describe ONE policy that would slow population growth, including its mechanism.

Describe a SECOND, different policy, including its mechanism.