Sample Quiz 5 answers

1-B (carrying capacity is number of “individuals” that can be sustained- they can be male or female or any combination of both)

2-D (Mackenzie Fig. 9.1)

3-E

4-C

5-C (Mackenzie Fig. 10.13) In tropical rainforests, the overwhelming portion of carbon and nutrients are in the biomass (not dead organic matter in soils)

6-B

7-C

8-D (“calcining” is heating up limestone to produce lime, which release CO₂: CaCO₃àCaO + CO₂)

9-C (this material will be on next quiz)

10-A (Mackenzie Fig. 7.5)

11-C (Mackenzie Fig. 9.26)

12-D

13-E (Mackenzie Fig. 9.20; world usage is in Fig. 9.18)

14-C (the unknown or unaccounted for sinks are now known to likely be forest re-growth in temperate and tropical regions)

15-D – Natural resources, energy, and interactions all contribute to an area’s carrying capacity

16-D

17-A – Conversion of forest to pasture, resettlement, and debt repayment contribute to deforestation now

18-C – Malthus believes the population will continue to grow rapidly unless various forces (e.g., disease, war, famine) act to reverse it

19-C (this material will be on next quiz)

20-A (formation of caves below the subsurface could natural occur, and their collapse would cause subsidence (this material will be on next quiz)

21-D – $44 billion of which $27 billion are “on-site” costs and $17 billion are “off-site” costs [$400 billion estimated for whole world] (this material will be on next quiz)

22- C – 1 billion tons, which is 1000 billion kg (1 trillion kg)

23-inputs to atmosphere total 6.3+2.2= 8.5GtC, of which the atmosphere is retaining 3.3 GtC and the oceans are taking up 2.4 GtC. Thus a total of 3.3+2.4=5.7GtC is accounted for of the 8.5GtC going in, but that means 8.5-5.7=2.8GtC is unaccounted for as part of the so-called “missing sink”. Around 2000, the prevailing wisdom was that it was going into temperate N. Hemisphere forests (N. America and China), or into the southern Ocean, but some recent evidence suggests much of it may be going into tropical rain forests related to CO₂ fertilization or secondary regrowth in areas that were deforested.

24-

Example 1: Photosynthesis is the main component of primary production, and it requires the C from CO2 as a primary nutrient, but productivity also requires other nutrients such as N. Thus primary production is a major sink for N and C in their respective biogeochemical cycles.

Example 2: when fossil fuels are combusted they contain lots of C, but they also contain some N. Both will go into the atmosphere when the fuel is burned (Mackenzie Table 6.1)

25- No. During the full glacial 20,000 years ago, a continental ice sheet covered much of N. America as far south as St. Louis. Therefore, the remaining forest was compressed into latitudes below this

26-Yes. 7-8 GtC is currently entering the atmosphere from f-f burning each year, but around 200 GtC per year enter the atmosphere from respiration+decomposition on land +evasion from the ocean. Thus f-f inputs are around 5% of the natural inputs. So, why then are we concerned with it?

27- Mexico has a broader base, with a greater fraction of individual in the pre-reproductive age classes (primed for rapid population growth). The US distribution is more uniform with reduced fraction of individuals in pre-reproductive age classes and a higher fraction in post-reproductive age classes. (Mackenzie Fig. 9.14)

28-productivity/oxygen production/biodiversity/genetic storehouse/tropical pharmacy/C storage

29- forest to agriculture; forest to pasture; farmland to highways; etc.

30- birth rate, death rate, immigration/emigration (known as dispersal), sex ratio, age distribution

31- 20 years (use “rule of 70”)

32- eventual peak production (year) of oil worldwide, after which oil availability/production will decline and maybe calamity and disaster will occur if other energy sources are not available to replace it (see video link in syllabus)