Ecology Review
Modified True/False
Indicate whether the statement is true or false. If false, change the identified word or phrase to make the
statement true.
1. In any location on Earth, there is usually an increase in temperature with an increase in elevation.
____________________
2. The two most influential factors in determining the plant and animal life in an ecosystem are
precipitation and temperature. ____________________
3. Oceans have a lower heat capacity than land masses. ____________________
4. The leeward side of a mountain range has less moisture and precipitation than the windward side.
____________________
5. Canada is composed of two of the world’s biomes. ____________________
6. Temperate rainforests contain most of the world’s terrestrial organisms. ____________________
7. Caribou, musk, oxen, and arctic foxes are adapted to life in the Taiga biome. ____________________
8. Conifers dominate the temperate deciduous forest biome. ____________________
9. Animals well adapted to eliminate extra heat and conserve water are typically found in the desert
biome. ____________________
10. There are 14 different biogeoclimatic zones in British Columbia. ____________________
11. An adaptation is a learned trait that improves an organism’s chance of survival and reproduction.
____________________
12. Some lizards successfully blend into their surroundings. This adaptation is known as mimicry.
____________________
13. An example of mimicry may occur between a plant and an insect as in the following example. The plant
may evolve a chemical toxin to keep the insect away, and, in turn, the insect may evolve resistance to
the toxin. ____________________
14. Natural selection is a process that favours the survival of organisms with traits that are best adapted to
the environment. ____________________
15. When organisms of the same species compete for food and other resources, it is called resource
partitioning. ____________________
16. There are more organisms at top trophic levels than at bottom trophic levels. ____________________
17. When a forest is burned down due to pest infestations, the pioneer species is pine.
____________________
18. Extinction occurs when a species has completely gone from Earth. ____________________
19. The dominant species in an ecosystem is the species whose presence plays an important ecological role
in determining what other species live in the community. ____________________
20. Interspecific competition occurs between different species competing for the same resources.
____________________
21. Earth obtains new matter from meteorites. ____________________
22. Calcium carbonate is an organic compound. ____________________
23. Compounds containing carbon and hydrogen are called organic compounds. ____________________
24. Carbon dioxide is an organic compound. ____________________
25. Photosynthesis is the process in which carbohydrates and oxygen react to produce energy, carbon
dioxide, and water. ____________________
26. In cellular respiration, the reactants are oxygen and glucose. ____________________
27. Oxygen and glucose are products of photosynthesis. ____________________
28. Oceans, forests, and fossil fuels are important carbon garages, because they store and release carbon
slowly. ____________________
29. Most of the carbon is cycled through the biosphere via two processes called digestion and
decomposition. ____________________
30. Carbon dioxide and methane are two carbon-containing greenhouse gases. ____________________
31. Methane is the most abundant greenhouse gas. ____________________
32. Anaerobic organisms require oxygen in order to perform respiration. ____________________
33. The most abundant gas in the atmosphere is oxygen. ____________________
34. During nitrogen fixation, nitrogen gas is converted into ammonia. ____________________
35. Peas, peanuts, soybeans, clover, and alfalfa are specialized plants known as phytoplankton.
____________________
36. Nitrogen fixation is the process that produces nitrate from ammonium. ____________________
37. The conversion of nitrates to nitrogen gas by bacteria is called nitrification. ____________________
38. Plant species that live in bogs can tolerate high levels of nitrogen. ____________________
39. When algae decompose in fresh water, the amount of oxygen in the water decreases.
____________________
40. Mycorrhizae, a type of fungus found on some plants, increases the solubility of soil and fertilizer
phosphates. ____________________
41. Tornadoes are natural weather events resulting in lots of snow with drifts and ice forming.
____________________
42. Hurricanes are caused by high winds and low pressure resulting in a swirling funnel cloud that acts like
a vacuum cleaner as it touches the ground. ____________________
43. Resin is the younger wood just inside the bark of a tree, where most of the tree’s nutrients are
transported. ____________________
44. A drought results in water sources drying out and the soil becoming hard packed.
____________________
45. The severe shaking of Earth’s crust resulting in landslides, liquefaction, and fissures is known as a(n)
avalanche. ____________________
46. In order to neutralize an acidic lake, a basic substance such as lime may be added.
____________________
47. A pH level below 7 indicates the substance is basic. ____________________
48. The water in acidic lakes is typically murky. ____________________
49. Thermal energy is considered a(n) air pollutant. ____________________
50. Organic waste is a pollutant because it depletes oxygen as it decomposes. ____________________
51. Biomagnification has the greatest effect on organisms at the lowest trophic levels.
____________________
52. Due to their diets, studies have shown higher levels of PCBs, PBDEs, and chlordanes in coastal grizzly
bears compared to interior grizzly bears. ____________________
53. Chemical substances called pollutants are used to control organisms that humans consider to be pests.
____________________
54. DDT, a synthetic pesticide, was widely used to control plant pest populations. ____________________
55. DDT, a synthetic pesticide, is a fat soluble substance. ____________________
56. The fewer the number of trophic levels, the greater the levels of biomagnification.
____________________
57. Copper, a common heavy metal, is used in pressure-treated lumber, pesticides, and smelting.
____________________
58. Copper is a common heavy metal used in dental fillings, thermometers, and in the production of
batteries. ____________________
59. Endocrine-disrupting compounds affect developing embryos by acting like natural hormones.
____________________
60. Soil deposition results when fertile topsoil is lost to erosion and soil nutrients are depleted.
____________________
Essay
1. Explain the term biodiversity. Why does biodiversity exist, rather than one species outcompeting all
others?
2. A mature forest is destroyed by a natural forest fire. Describe the stages of succession in order for the
community to be restored.
3. Many of the fertilizers we use in agriculture have not been tested for their sustainability and long-term
effects. In your opinion, do the benefits of chemical fertilizers outweigh the costs? Be sure to include
both the advantages and disadvantages of using fertilizers in your answer.
4. Can ecosystems “lose” nutrients? If so, where do they go? If not, what happens to the nutrients?
5. The forestry industry has had a major impact on B.C. ecosystems. What are some impacts that have
occurred directly as a result of forestry, and how have they positively and negatively affected humans
and the environment?
6. Compare and contrast the uses of biological pest controls and pesticides. What are the advantages and
disadvantages of each method of pest control?
Ecology Review
Answer Section
MODIFIED TRUE/FALSE
1. F, decrease
2. T
3. F, higher
4. T
5. F, five
6. F, Tropical rainforests
7. F, Tundra
8. F, boreal forest
9. T
10. T
11. F, genetic
12. F, camouflage
13. F, coevolution
14. T
15. F, intraspecific competition
16. F, less, fewer
17. F
algae
grasses
small shrubs
18. T
19.
20.
21.
22.
23.
24.
25.
26.
27.
28.
29.
30.
31.
32.
33.
34.
35.
36.
37.
38.
39.
F, keystone
T
T
F, inorganic
T
F, inorganic
F, Cellular respiration
T
T
F, reservoirs
F, photosynthesis and
cellular respiration
T
F, Carbon dioxide
F, Aerobic
F, nitrogen
T
F, legumes
F, Nitrification
F, dentrification
F, low
T
40.
41.
42.
43.
44.
45.
46.
47.
48.
49.
50.
51.
52.
53.
54.
55.
56.
57.
58.
59.
60.
T
F, Blizzards
F, Tornadoes
F, Sapwood
T
F, earthquake
T
F, acidic
F, clear
F, water
T
F, highest
T
F, pesticides
F, insect
T
F, greater
F, Arsenic
F, Mercury
T
F, degradation
ESSAY
1. Biodiversity refers to the number of different species and the number of individuals of each species found in the ecosystem.
The reason why biodiversity exists is because each organism has its own ecological niche and role to play in the
environment. The different trophic levels in a community ensure that each organism has a specific job. For example, it is the
role of decomposers to recycle nutrients consumed by higher order consumers back into the environment such that they are
usable by primary producers. Thus, nutrients and energy are cycled through the environment, allowing for biodiversity to
exist. Additionally, biodiversity can exist because organisms have the ability to partition their resources. This means that
species develop traits that allow them to use the same resource either in different ways, in different places, or at different
times.
2. If a mature forest was destroyed by a forest fire, secondary succession would occur. This means that the land would still
have soil and sediments. Pioneer species would include plants and weeds that would begin to grow within a few weeks.
Seeds would either come from animals or from the soil itself. Over time, the plants and weeds would attract herbivores.
These herbivores would, in turn, likely attract omnivores and carnivores. Eventually, the forest’s plant and animal life would
return (although not necessarily all the same species), and would eventually develop into a climax community.
3. Answers may vary, however, the student should include the many advantages and disadvantages of chemical fertilizers in
their response. Specifically, fertilizers have the benefit of increasing crop yields, increasing profits, decreasing production
costs, and increasing nutrient availability for agricultural crops. Costs of fertilizers include high energy consumption (to
produce the fertilizers), the release of nitrous oxide into the atmosphere, no organic material being added to the soil, and the
nutrients leaching into the soil and ground water and contaminating the ecosystem.
4. There is no real starting or ending point in nutrient cycling. Instead, nutrients cycle between biotic and abiotic components
of the ecosystem. This means nutrients are released from non-living sources such as soil, water, and air and then become
available for organisms. The organisms then die and decompose, returning nutrients back into the abiotic components of the
environment. In this way, nutrients continue cycling throughout the ecosystem without ever being “lost.”
5. The forestry industry, one of B.C.’s most important industries, has had a major impact on the environment. One percent of
B.C.’s forests are logged each year, which is a rate that is unsustainable. Although the forestry industry provides many
advantages for humans, including the production of paper products and lumber for houses and furniture, it is not without its
cost. Some consequences of logging include loss of habitat for organisms and the disruption of the balance of carbon in the
environment. This is because forests act as carbon reservoirs and when they are removed, they no longer can absorb carbon
dioxide from the atmosphere. The result is higher levels of
(a greenhouse gas) in the air, which contributes to global
warming. In addition forests are important for recreation and tourism and the loss of forests has been negative for these
industries.
6. Biological pest control is the use of natural methods through the introduction of a natural predator to control a pest
population. Although biological pest control will not eradicate a pest population, it will significantly reduce it. In biological
pest control, unlike chemical pesticide programs, a pest cannot grow resistance. Other advantages of biological pest control
is that they usually do not have the same negative effects on the environment by contaminating soil and groundwater, and if
successful, the natural balance of the ecosystem may remain fairly undisturbed. A disadvantage of biological pest control,
however, is that it may not be as economical as a chemical pesticide. Also, chemical pesticides are usually fast-acting,
readily available, and easy to use, unlike natural pest-control measures. Both methods have their advantages and
disadvantages, however, it would appear that biological pest control is much friendlier to the environment.