Download IB 203 Practice Exam Answer Key (Exam 1) 2006

IB 203 Practice Exam Answer Key (Exam 1) 2006
1) Biomes (Ch 5)
A. Tropical rainforest
Tropical seasonal forest/savanna
Subtropical desert
B. Neither rain nor temperature are limiting.
Rain is limiting for several months of the year.
Rain is limiting throughout the year.
C. See Fig. 5.13 in textbook
2) Climate (Ch 4)
A I would prefer to establish my garden on the west side of the Cascade
Mountains.
B In temperate latitudes, the prevailing winds are from the West. The Cascades are on
the west coast of North America and receive moist air from the Pacific Ocean. As
these air masses cross the mountains, they rise and cool. This reduces the waterholding capacity, and abundant rainfall results. As the air crosses the mountains, it
descends and warms again, increasing the water holding capacity, resulting in a dry
climate (rain shadow) on the eastern side. High rainfall on the western side would
promote growth of a lush temperate garden. In addition, temperatures on the western
side would be moderated by the Pacific Ocean.
Prevailing winds also move from west to east over the Appalachian and Ural
Mountains. However, the Urals are far from any oceanic moisture source and would
have a more extreme continental climate. The Appalachians are near the Atlantic
Ocean and Gulf of Mexico, which provide moisture to both sides of the mountains.
Because the prevailing winds are westerly, and the Appalachians are far removed from
western moisture sources, no rain shadow will develop. In addition annual
precipitation in the Cascades would exceed that of the Appalachians.
C No, my choice would still be on the west side of a mountain range that is near the
west coast of a continent or island because the prevailing winds in the Southern
temperate region (30-60 S) are also from the west.
3) Osmotic balance (ch 2-3)
A. The marine shark’s osmotic potential is equivalent to that of sea water,
while the marine salmon’s is much lower than sea water.
Urea contributes to only the marine shark’s osmotic potential.
B. Marine salmon. They are hypo-osmotic (concentration of solutes is less than
seawater). Therefore, they are continuously losing water, and must continuously drink
water to replace the passively lost water.
C. Marine salmon. They spend energy excreting ions ingested with the seawater
against a concentration gradient.
D. Freshwater sharks would not have urea in their body fluids. Marine sharks have urea
to balance their osmotic potential with that of seawater. Freshwater has a much lower
osmotic potential than seawater, and so freshwater sharks would not need to maintain
high urea levels. If they had high urea levels, water would continuously rush in, and so
they would need to expend energy excreting this excess water.
4) Dissolved nutrients in soil (ch 2-3)
A. If plant species are adapted to soil of particular nutrient makeup in their native
environment, then plant species will be more productive in native than non-native
soils.
Or If plant species evolve to best exploit the soil conditions to which they are
native, then species will be more productive in native than non-native soils.
B. Lodgepole pine and Sargent cypress
C. competition with another species, herbivory, fire, acid rain, inappropriate
precipitation, or temperature.
5) Acclimation (ch 9)
A Do different species have varying abilities to acclimate to temperature?
B. Larrea: The moderate temperature plants have their peak photosynthetic rate at a
lower temperature than the high temperature plants, but the value of these
maximum rates are similar.
Tidestromia:The moderate temperature plants’ photosynthetic rate peaks at a lower
temperature than the high temperature plants, and the high temperature plants have
a higher rate of PS than low tempeature plants at all temperatures, especially at
high temperatures.
C.
Larrea: moderate mean; low range
Tidestromia: high mean; low range
D. Some plant species can change their phenotype (acclimate) as temperature changes
enabling them to maintain high photosynthetic rates in a variable environment.
6) Adaptation (ch 16)
A. If the insect is adapted to its specific tree,
then it will survive more poorly when transplanted to another tree than to another
branch of its own tree.
B. The proportion experiments with lower % survival is lower when transplanted
between trees than when transplanted between branches of its own tree.
C. Yes.
D. Natural selection would be a more powerful force. Gene flow is very limited because
the insect has limited movement. Therefore, natural selection would result in adaptation
of the insect to specific conditions in a very local environment.
E. The genetic makeup of the population of scale insects would be differentiated.
The fact that insects moved between trees were more likely to die shows that they are not
adapted to neighboring trees. Assuming natural selection would be different between
trees, then the population would have different combinations of genes on different trees.
7) Life history tradeoffs (ch 10)
A. Seed size decreases as seed number increases (or Seed number decreases as seed
number increases).
Because of limited resources, a plant can either put all its effort into producing a few
large seeds or it can distribute the same amount of resources among many small seeds.
There are generally not enough resources available for the plant to produce many
large seeds.
B. Adult survival decreases as the number of offspring in any given breeding event
increases.
Successfully raising offspring requires a lot of energy and resources from the parent(s).
As there are limited resources available, the parent cannot raise offspring without
sacrificing some of its own resources. For example, collecting more food for the
offspring means that the parent is collecting less food for itself. Because raising
offspring is so taxing on the parent, it increases the chance that the parent will not survive
to the next breeding event.
8) Mating system (ch 11)
A. Bar graph, one bar for males, one for females and with equal heights.
B. Males; have more variable mating success than females. Add large error bar
to males; a small error bar to females
C. Because this is a polygynous species, one male mates with many females. In the case
of the elephant seals (as mentioned in the book), a few males are dominant and form
harems of females, which they defend from all other males. So those few males have
very high mating success, but the many non-dominant males have very low reproductive
success. This leads to the very high variability in the mating success of the males. There
is little variability in female mating success, as nearly all are mated by the dominant
male.