Download DBQ on p. 185 – April 15, 2013

Exam Questions on Topic 5 (p. 46) – April 17, 2013
1)
a) S-shaped
b)
i) Line that reaches at plateau at year 8.
c)
i) If all the female birds in the original sample had survived, the
population probably would have reached the carrying capacity earlier than by year 8.
ii) The carrying capacity itself wouldn’t be different.
2)
a) I = secondary consumer, II = primary consumer, III = producer
b) Chemical energy
c) The line from the Sun to box III.
d) Waste energy
3)
a) The methane emissions contribute to the enhanced greenhouse effect (as
methane is an example of a greenhouse gas), which results in an overall increase in
the Earth’s average temperature. However, in order for this to happen, the amount of
methane released must be greater than the amount taken in from the atmosphere.
b) The release of methane is a natural process, but humans have caused the
amount released to be increased.
c) Combustion of fossil fuels and meat production could be decreased by
establishing maximum amounts for each one.
Chapter 16 questions – April 17, 2013
1)
a) Scientists could have chosen such areas because they are generally
uncontaminated by pollution as they are far away from major cities.
b) Both graphs have shown an overall increase in the CO2
concentration/ppm; however, the graph for Alert station, Canada shows seasonal
fluctutations that are clearly more dramatic than shown in the graph for Baring Head,
New Zealand.
c) The seasonal fluctuations are caused because plants photosynthesize –
and consequently take in CO2 – in the summer but not so much in the winter. The
northern hemisphere has a greater land mass than the southern hemisphere, which
means that it has more dramatic seasonal fluctuations in the CO2 concentration. The
southern hemisphere has a smaller land mass, meaning that even if the plants stopped
photosynthesizing – and taking in CO2 – the difference in CO2 concentrations wouldn’t
be as dramatic.
2)
a) As the latitude became closer to the north pole, the day-length to enter
hibernation increased. Conversely, as the latitude became closer to the equator, the
day-length to enter hibernation decreased.
b) The graph for 1972 had a steeper slope than that of 1996, which shows a
shorter day-length to enter hibernation; however, they started out similarly and both
show a direct relationship between day-length and latitude for larval populations.
c) Warmer temperatures mean that prey species end hibernation early,
which presents an advantage to the mosquito that hatch earlier for fixed day-length.
3)
a)
i) 330 ppm
ii) 330 ppm – 310 ppm = 20 ppm
b)
i) The first seven hours of the day (0~7 hours).
ii) Plants near the ground produce CO2 in cellular respiration.
Because the CO2 is unlikely to be blown away (by the wind) when it is at such low
heights, the concentration would be higher than at the canopy.
c) 8AM
4)
a) Plankton
b) It increased at a decelerating rate, then it started to decrease at an
accelerating rate at approximately the 7th day.
c) Increasing quantities would be found in the sediment as the organisms
excreted waste (which includes the 32P), which then collects in the sediment, trapping
the 32P there.
DBQ on p. 190 – April 17, 2013
1) Identify the code for the least optimistic emissions scenario.
AIFI
2) State the minimum and maximum forecasts for average global temperature change.
The maximum by 2100 is 4.5 and the minimum is 2.
3) Calculate the difference between the A2 and B2 forcecasts of global average
temperature rise.
7.1 – 5.1 = 2.0
4) Compare the forecasts for arctic temperatures with those for global average
temperatures.
The forecasts for arctic temperatures are less optimistic than those for global average
temperatures. The A2 forecast is clearly the most pessimistic, but the B2 forecast is
within the range of the most of the global average temperature forecasts.
5) Suggest uncertainties, apart from greenhouse gas emissions, which affect forecasts
for average global temperatures over the next 100 years.
Uncertainties could include
6) Discuss how much more confident we can be in forecasts based on data from a
number of different research centres, rather than one.
We can be more confident in forecasts based on data from a number of different
research centres for the same reasons that conducting multiple trials is preferable in
experiments – the more trials there are, the less random error there is. We cannot
have much confidence in a forecast based on data from just one research centre
because there could have been a systematic error that rendered the data invalid.
Forecasts based on a number of different sets of data allows for anomalies to be
identified (and possibly discarded); however, it is not impossible for all of the sets to
have been limited by the same (or even different) errors.
7) Discuss whether the uncertainty in temperature forecasts justifies action or
inaction.
To climate skeptics, the uncertainty in temperature forecasts may justify inaction
because it could seem pointless to take measures against something that does not
exist – time, effort, and money could instead be spent on other more tangible issues.
However, another perspective could be that uncertainty in temperature forecasts does
not justify inaction because (like Robert van Lierop says) taking action only when
climate change becomes a concrete problem may be ineffectual; we need to take
action now when we can still ameliorate the situation.
8) Discuss whether it is possible to balance environmental risks with socio-economic
and livelihood risks or do priorities need to be established.
It could be possible to balance environmental risks with socio-economic and
livelihood risks by spending equal amounts of time/money/effort on both; however,
in order to be as efficient as possible, it could be better to establish priorities. It can be
predicted that in order to tackle the environmental issues as effectively as possible,
there may be temporary socio-economic setbacks. This wouldn’t be a trade off that
would be acceptable if both considerations were equally prioritized, meaning that the
solution might be more gradual and complicated (because there are more things to
take into consideration).
DBQ on p. 185 – April 15, 2013
1) Deduce what the “above ground” compartment consists of in an ecosystem.
Plants.
2) State which biome has the largest “above ground” compartment.
Equatorial forest.
3) Explain why it is difficult to grow crops in an area where equatorial forest has been
cleared of its vegetation.
In this ecosystem, most of the nitrogen is stored in the “above ground” compartment –
when the vegetation is cleared, so is most of the nitrogen. Plants need nitrogen, so
crops that are grown in this area (which has little nitrogen), they will not thrive.
4) State the name of the process carried out by decomposers and detritus feeders that
releases CO2 into the atmosphere.
Respiration.
5) Suggest why most of the nitrogen in a tundra ecosystem is in the soil.
A tundra is a treeless region that has a frozen subsoil. The lack of trees means that not
much nitrogen can be stored above ground and the frozen subsoil means that there is
little space for roots. Therefore, most of the nitrogen would have to be stored in the
soil.
6) Explain why warming due to climate change might cause a release of CO2 from
tundra soil.
Climate change can cause the frozen subsoil in the tundra to melt. The subsoil stores a
lot of carbon, which is released as carbon dioxide and methane when this happens.
DBQ on p. 181 – April 11, 2013
1) Compare the roles of Belostoma bakeri and Ranatra montezuma within the food
web.
Belostoma bakeri and Ranatra montezuma are both at the top of the food web,
although they both can be secondary, tertiary, and quaternary consumers. A
difference is that the Belostoma bakeri population has a little more than double the
biomass that the Ranatra montezuma population does.
2) Deduce, with a reason, which organism occupies more than one trophic level.
The organisms that occupy more than one topric level are both the Belostoma bakeri
and the Ranatra montezuma.
3) Deduce using P values:
a) what would be the most common food chain in this web?
b) what is the preferred prey of B. bakeri?
Hyalella montezuma
4) Construct a pyramid of energy for the first and second trophic levels.
5) Calculate the percentage of energy lost between the first and second trophic levels.
(427078 + 234342702) - 30960000
) ´100
(427078 + 234342702)
(661421022) - 30960000
% of Energy Lost = (
) ´100
661421022
% of Energy Lost = (
% of Energy Lost = (
630461022
) ´100
661421022
% of Energy Lost ≈ 95%
6) Discuss the difficulties of classifying organisms into trophic levels.
It is difficult to classify organisms into trophic levels if they consume at different levels
7) Outline the additional information that would be required to complete the pyramid
of energy for the third and fourth trophic level.
DBQ on p. 180 – April 10, 2013
1) Suggest a method that might be used to deduce the trophic level of a fish once it is
captured.
Collecting the feces of the fish and identifying undigested material in it, which in turn
helps to identify the species that the fish has consumed.
2)
a) Compare the changes in mean trophic level of landed fish from marine and
freshwater fisheries since 1970.
The mean trophic level of landed fish from both marine and freshwater
fisheries has decreased since 1970, although the decrease from 1970~2000 has been
more dramatic for freshwater fisheries at approximately 0.4 – for marine fish it
decreased by approximately 0.2.
b) Suggest why there is a difference in the two trends.
There could be a difference in the two trends because the availability of
resources is different in the two regions (saltwater vs freshwater).
3) Explain why the mean trophic level might increase with the age of an individual
fish.
The mean trophic level might increase with the age of an individual fish because
generally, the older fish are, the larger they are. Larger fish tend to consume more
species, putting them higher up in the trophic level.
4) Deduce the change in age of captured fish over the period shown.
Because there is generally a direct relationship between age and trophic level, the
graph shows that the age of captured fish seems to have decreased over the period
shown.
5) Explain two advantages of humans catching and consuming fish at a lower mean
trophic level.
One advantage of humans catching and consuming fish at a lower mean trophic level
is that energy transformations are more efficient. Because energy is lost with each
transformation, fewer transformations result in less energy that has been lost. A
second advantage is that consuming fish at lower mean trophic levels allow fish at
higher mean tropic levels to grow (because overfishing large fish has led to depletion
of the supply of such fish).
DBQ on p. 176 – April 8, 2013
1) Which of the organisms is autotrophic? Euglena and venus fly trap can be
autrotrophic.
2) Which of the organisms is heterotrophic? Ghost orchid and dodder. Euglena and
venus fly trap can also be heterotrophic.
3) Of the organisms that are heterotrophic, deduce which is a consumer, which a
detritivore and which a saprotroph. Venus fly trap is a consumer, ghost orchid and
ghost orchid are detritivores, and dodder is a saprotroph.