Practice Exam 3
This is a study guide. Very few of these exact questions will be used on your exam.
They simply serve as examples of the kinds of questions asked. A key will be handedout at the end of a lecture. It is best to answer the questions on the sample exam before
you check your answer with the key.
Choose the Best Answer
1. Natural communities have:
a. very low species diversity with a few species that are common and other
species that are rare.
b. very low species diversity with all species about equally common.
c. high species diversity with a few species that are common and other species
that are rare.
d. high species diversity with all species about equally common.
2. Which of the following disturbances is frequently responsible for preventing trees
from establishing in grasslands?
a. volcanoes
b. windstorms
c. fire
d. glaciation
3. Which of the following is not correlated with species diversity?
a. latitude
b. productivity
c. longitude
d. resilience
Questions 4-6 refer to the hypothetical food web given in your laboratory manual.
QuickTime™ and a
TIFF (Uncompressed) decompressor
are needed to see this picture.
4. Atmospheric carbon would enter the food web through which organisms?
a. Bacteria
b. Snails
c. Water Fleas
d. Coontail
e. Damselfly Larvae
5. If the following species were members of a simple food chain, which would contain
the most biomass?
a. Water Fleas
b. Dragonfly Larvae
c. Back Swimmers d. Damselfly Larvae
6. A few micrograms of Strontium 90 was added to this ecosystem. After several
months, which species would be expected to show the lowest levels of this isotope?
a. Water Fleas
b. Dragonfly Larvae
c. Back Swimmers d. Damselfly Larvae
Questions 7 & 8 refer to an energy budget for a population of saddled prominent moth
caterpillars in Hubbard Brook Forest.
7. During the study period, caterpillars assimilated 82 kilocalories per square meter per
year from the 576 kilocalories of the tree leaves that they consumed. How many
kilocalories were in the “frass” they egested?
a. 658
b. 494
c. 104
d. 31
e. 7
8. Of the 82 kilocalories assimilated by these moth caterpillars, 31 kilocalories were
stored as growth and reproduction. What proportion of assimilated energy is used for
respiration?
a. 0.98
b. 0.81
c. 0.75
d. 0.62
e. 0.38
9. One of the lessons from a pyramid of energy is that:
a. only one-half of the energy in one trophic level is passed on to the next level.
b. eating grain-fed beef is an inefficient means of obtaining the energy trapped
by photosynthesis.
c. most of the energy from one trophic level is incorporated into the biomass of
the next trophic level.
d. the energy lost in cellular respiration is 10% of the available energy in each
trophic level.
e. the efficiency of energy conversion is highest for primary consumers.
Questions 10 & 11 refer to the following energy flow diagram for an oak-pine forest at
Brookhaven National Laboratory. Energy flow equivalents (*) are expressed as grams of
dry matter per square meter per year.
QuickTime™ and a
TIFF (Uncompressed) decompressor
are needed to see this picture.
10. What is the net production by plants in this community?
a. 500*
b. 620*
c. 700*
d. 1,200*
e. 2,650*
11. What proportion of gross production goes to decomposers?
a. 0.234
b. 0.517
c. 0.631
d. 620*
e. 700*
12. Although free nitrogen is abundant in the atmosphere, most living things are
unable to use it until it is “fixed” as ammonia and converted into nitrites and
nitrates. Only
are able to fix and convert nitrogen.
a. plants. b. protozoa.
c. bacteria.
d. fungi
e. All of these groups;
only animals can’t.
13. Concerning the nitrogen cycle, which of these is NOT true?
a.
b.
c.
d.
e.
It requires a number of different types of bacteria.
Plants take in and utilize N2 from the air by way of leaves.
Bacteria convert ammonia ( NH3 ) to NO3, which can be used by plants.
Eventually, organic nitrogen becomes inorganic nitrogen again.
Animals get their nitrogen from amino acids made by plants.
14. It is clear that per plant biomass is higher when Indian Grass is grown at low density
rather than high density. This is most likely due to the fact that:
a. Indian Grass produces toxic substances that kill Indian Grass seedlings.
b. Indian Grass grows really tall when crowded and shades out other smaller
plants.
c. at least 300 mg of nitrogen per plant is need for Indian Grass to grow.
d. individual Indian Grass plants compete; such that, the nitrogen taken up by
one plant is not available to any other.
e. the nitrogen in the air is more concentrated in areas where there are fewer
plants and thus plants at low density require less soil nitrogen.
15. The phosphorus cycle differs from that of carbon and nitrogen in that:
a. it lacks a liquid phase.
b. it lacks a gaseous phase.
c. living organisms do not need phosphorus.
d. only phosphorus is cycled through marine organisms.
e. the phosphorus cycle does not differ importantly from the carbon and
nitrogen cycles.
16. Scientists at Hubbard Brook demonstrated that clear-cutting had what effect on
ecosystem dynamics. It increased:
a. aboveground biomass.
c. nutrient export.
b. secondary production.
d. the pool of soil organic matter.
17. The movement of matter and energy through ecological systems obeys the same
laws of thermodynamics as is found in all physical systems. These laws indicate that:
a. both matter an energy recycle.
b. neither matter nor energy can recycle.
c. matter recycles, but energy does not. d. energy recycles, but matter does not.
18. The increase in algae due to the addition of nutrients to water sources such as
streams, lake, and rivers is called:
a. eutrophication.
b. decomposition.
c. biomagnification. d. transpiration.
19. DDT and strontium 90 are examples of hazardous materials that accumulate
through biomagnification after being released into the physical environment. The
concentration of these materials tends to be:
a. higher in producers and lower in upper level consumers.
b. particularly high in drinking water.
c. exceptionally high in decomposing organic matter.
d. highest in animals at the end of a food chain.
e. equally high in producers and animals at the end of the food chain.
20. The recent increase in atmospheric CO2 concentration is mainly a result of an
increase in:
a. primary productivity.
b. the biosphere’s biomass.
c. the absorption of infrared radiation escaping from Earth.
d. the burning of fossil fuels and wood.
e. cellular respiration by the exploding human population.
21. U. S., China, Russia, Japan and India are responsible for over half of the world
carbon emissions from fossil fuels. What proportion of total world carbon emissions are
due to fossil fuel use in the U. S.?
a. 1 %
b. 5%
c. 10%
d. 25%
e. 40%
22. Ammonia and oxides of nitrogen are being added to the atmosphere at rates higher
than carbon emissions. Their return to the land in rainfall is called:
a. nitrogen fixation. b. nitrogen deposition.
c. nitrogen addition.
d. nitrogen emission.
e. nitrogen fertilization.
23. If nitrogen deposition is around 15 kg / ha, how many g/m2 of nitrogen is added to
the soil? (Hint: 1 hectare (ha) = 100 x 100 meters)
a. 15,000
b. 1,500
c. 150
d. 15
e. 1.5
24. Biological diversity is an index of the variety of living organisms in an area. It
includes:
a. species diversity only.
b. species, genetic, and ecosystem diversity.
c. species, biosphere and ecosystem diversity.
d. population and ecosystem diversity.
e. genetic diversity only.
25. Human activities resulted in the replacement of natural communities such as native
forests. For example, most of the changes in forest area in Green County,
Wisconsin occurred between:
a. 1950-1996
b. 1902-1950
c. 1882-1902
d. 1831-1882
Questions 26 & 27. A number of primary causes of the endangerment or extinction of
species on the local or global level have been proposed. Some of these are listed
below:
a. habitat destruction.
b. over exploitation.
d. introduction of predators.
c. introduction of exotics.
e. climate change.
26. Human activities that convert natural areas into farms, dwellings, industries, places
of business, and corridors for transportation causes the decline of native populations of
plants and animals. This is called:
27. Which of the following is NOT currently a major cause of population extinction?
28. When forested habitats are fragmented, why does their quality decline?
a. Trees on the edge of the fragments are frequently blown down.
b. The edges of the forest are exposed to more sunlight, which increases
temperatures and decreases humidity.
c. Weedy species from the deforested areas invade the edge.
d. All of the above.
29. Which of the following is not one of the 4 principals of harvesting?
a. Harvest can result in extinction.
b. Any harvest reduces abundance.
c. At some level of harvest there is a level of maximum sustainable yield.
d. Harvesting the youngest reproductive females gives maximum yield
without lowering reproductive output of the population.
e. Below a certain harvest level populations are resilient and show increased
survival or individual growth to compensate for removals.
30. The local extinction of species is of great concern among those interested in
conserving biodiversity. For, example, it has been found that the loss of mammalian
species within western parks was, on the average,:
a. greatest when the species within the parks were the same as those outside
the parks.
b. lowest when rates of colonization were the lowest.
c. highest in parks that were most recently established.
d. greatest in parks that were smaller in size.
e. lowest when the populations of the same species outside the park were
smaller than those inside the park.
31. Which population is within the range of the size for a minimum viable population?
a. 3-6 individuals.
b. 20-50 individuals. c. 400-600 individuals.
d. 4,000-6,000 individuals.
e. 10,000-20,000 individuals.
Questions 32-34. A group of students conducting a biodiversity survey made the
following map of 0.10 square meter. Each numerical value (i. e. 1, 2, 3, ... etc.) inside a
square represents the location of a single plant of a given species. For example, the
number 31 shows the location of a plant belonging to the species False Sunflower; 16 is
a plant of Prairie Dock;10 is a Great St. John’s Wort plant; 1 is a Rattlesnake Master
plant; and so on for each number of 1 to 46.
3
25
29
31
27
3
27
26
10
1
29
32
27
32. What is the species richness for the above row?
a. 32.
b. 16.
c. 10.
d. 8.
e. 5.
33. What is the value of the species diversity index for the above row?
a. 0.125
b. 0.473
c. 0.910
d. 0.875
e. 0.000
34. If the area of the biodiversity survey were increased 10 fold, what would be the
expected number of species present in the community?
a. 160.
b. 100.
c. 32.
d. 20.
1
16
e. 5.
1
35. Viability analysis is a technique that uses survivorship, age of reproduction, age
specific fertility (maternity), and other demographic data to estimate the probability
that a population will persist for a given time into the future. This technique has
been applied to elephant populations for determining:
a. when to harvest .
b. how big an elephant reserve should be.
c. how old infants should be before sending them to zoos.
d. how old infants should be before releasing them into the wild.
36. By the early 1900’s wild turkeys were extinct in Michigan. Mating pairs were
reintroduced in the 1960’s. The current outlook for the statewide population of wild
turkey is:
a. bleak, the birds apparently can’t reproduce well.
b. good, the population has stabilized and hunting has resumed.
c. almost too good, the population has grown exponentially as indicated
by number of birds shot and eventually must be stabilized.
d. touch and go, the 91 birds in 1970 were able to increase to about 150, but
then the population declined and again is likely to become extinct.
37. Conservation biologists are interested in changes in the genetic structure of
populations. The loss in genetic variation when a population drops in size is commonly
called a genetic bottleneck. One of the ways of predicting the extent of loss in genetic
variation is to estimate the effective size of a population that experiences a genetic
bottleneck. If the numbers of individuals in 4 subsequent generations is:
N1 = 100
N2 = 10
N3 = 100
N4 = 200
What is the effective populations size?
a. 10 individuals.
b. 32 individuals.
c. 102 individuals
d. 200 individuals.
e. 410 individuals.
Questions 38-40 refer to the experiment performed by students using the same
procedure that we used this semester. Students working in BioS 101 in the Spring
Semester of 1997 obtained the following results for the accumulative number of
seeds that germinated since the beginning of the experiment.
S wamp Mi l kweed
N
u
m
b
e
r
G
e
r
m
i
n
a
t
e
d
50
Water
45
Fertil ize r
40
35
30
25
20
15
10
5
0
0
0
0
5
10
7
15
5
15
5
14
15
5
21
28
Days A fter Sowin g
38. How many germinated seeds (seedlings) from the Water treatment did the students
transplant on Day 14?
a. 0
b. 5
c. 10
d. 15
e. 20
39. Of the seeds that were pretreated with Fertilizer, a total of 15 germinated during the
course of the experiment. The highest number of seeds germinated between:
a. days 0 and 7.
b. days 7 and 14.
c. days 14 and 21. d. days 21 and 28.
40. Calculate the X2 for Water versus Fertilizer on day 28.
a. 50
b. 25
c. 12.5
d. 5
e. 1.6