CHAPTER
2
Self-Quiz
SUGGESTED ANSWERS
1.
(b); Choice (b) is correct because living things inhabit parts of the atmosphere, hydrosphere, and
lithosphere. Choice (a) is incorrect because the atmosphere is composed only of gases. Choice (c)
is incorrect because the hydrosphere is composed only of water. Choice (d) is incorrect because the
lithosphere is composed only of Earth’s outer solid shell, which includes Earth’s crust and the upper part of
the mantle.
2.
(a); Choice (a) is correct because the tundra has low temperatures most of the year. Choice (b) is incorrect
because grasslands have relatively long, warm summers. Choice (c) is incorrect because boreal forests have
longer growing seasons than the tundra. Choice (d) is incorrect because temperate forests have relatively
long, warm summers.
3.
(b); Choice (b) is correct because primary consumers eat plants, so they are known as herbivores. Choice (a)
is incorrect because producers generate their own food; they do not consume plants. Choice (c) is incorrect
because secondary consumers are carnivores. Choice (d) is incorrect because tertiary consumers are carnivores.
4.
(c); Choice (c) is correct because salinity determines the species that can survive in a particular aquatic
environment. It generally does not determine which species can survive in a terrestrial ecosystem.
Choice (a) is incorrect because aquatic and terrestrial ecosystems both depend on light for photosynthesis
by producers. Choice (b) is incorrect because aquatic and terrestrial ecosystems both depend on nutrients.
Choice (d) is incorrect because temperature determines the species that can survive in both aquatic and
terrestrial ecosystems.
5.
(c); Choice (c) is correct. The term is based on mutual benefit. Choice (a) is incorrect because only one
organism benefits in commensalism. Choice (b) is incorrect because the organism that loses during
competition is harmed. Choice (d) is incorrect because only the predator benefits from the relationship.
6.
(a); Choice (a) is correct because bacteria are living organisms and play a vital role in the food web.
Choice (b) is incorrect because sediment, like soil, is an abiotic (non-living) factor. Choice (c) is incorrect
because temperature is not a living component of an ecosystem. Choice (d) is incorrect because water is an
abiotic factor.
7.
False. Artificial ecosystems, or ecosystems established by human intervention, are usually not sustainable.
A true version of the statement would be: Artificial ecosystems require constant management to sustain the
balance of biotic and abiotic factors for which they were designed.
8.
False. Matter is recycled, but energy is not. A true version of the statement would be: Matter is recycled
and conserved in an ecosystem, but energy can enter and leave the ecosystem.
9.
True. Any gases leaving the Moon’s surface drift into space because the Moon’s gravity is too weak to hold
them.
10.
photosynthesis; Plants convert sunlight into chemical energy through the process of photosynthesis. This
chemical energy is then passed on to other organisms in the ecosystem.
11.
oxygen; Oxygen is needed for cellular respiration, a process that releases carbon dioxide, water, and stored
energy.
12.
species; All the organisms of given species living within the boundaries of an ecosystem form the
population of that organism in the ecosystem.
98
Unit B: Sustainable Ecosystems
55219_02_ch02_p043-100_pp4.indd 98
NEL
12/3/09 1:23:44 PM
13. (a)(ii)
Carnivores, such as sharks and hawks, eat only other animals; (b)(iii) Omnivores, such as bears
and people, eat both plants and animals; (c)(iv) Scavengers, such as vultures, eat the remains of dead and
discarded animals; (d)(i) Herbivores, such as deer and grasshoppers, eat only plants.
14.
Plants added oxygen to the atmosphere. Oxygen is an abiotic factor that makes animal life possible.
15. (a)
(b)
16.
Sample answer: Two biotic factors I may encounter are snakes and thorn bushes. Two abiotic factors I
may encounter are direct sunlight and large, arid stretches of land.
Sample answer: I will need high boots for protection from snake bites. I will need a long-sleeved shirt
and long pants for protection from thorns. I will also need sunscreen, sunglasses, and a wide-brimmed
hat to shield my eyes and skin from the Sun. I will bring several gallons of water to survive in the arid
land.
Sample answer:
kinetic energy
for life functions
gives off
electromagnetic
radiation as sunlight
kinetic energy
(gas and waste)
kinetic energy
(body growth and repair)
producer:
converts radiation to
chemical energy
17. (a)
(b)
18.
consumer:
converts chemical
energy to thermal
energy and
kinetic energy
The grasshopper population will increase because there will be fewer mice to compete for the grass and
less predation by the mice.
The meadow lark population will increase because they will have more grasshoppers to eat.
Sample answer: I will need to study the environment that includes my property and determine the food
sources available, such as plants and insects. I will need to research fish species to find a species that will
feed on these food sources. I will also need to find a fish species at a higher trophic level that will prey
on the fish species at the lower trophic level. I will need to stock the pond with fish in an appropriate
predator-to-prey ratio.
19. Table 1
20.
Sources of carbon
Destinations of carbon
Where carbon goes next
• food
• most beverages, except water
• inhaled carbon dioxide
•
•
•
•
• cell debris and excreted waste
eventually decompose and carboncontaining materials enter the soil
• carbon dioxide enters the atmosphere
cellular and intracellular materials
solid waste
liquid waste
exhaled carbon dioxide
Most nutrients that fish depend on are near shorelines, rather than in the middle of the ocean. Also,
sunlight needed for photosynthesis by plants at the bottom of aquatic food chains does not penetrate into
very deep water.
NEL
55219_02_ch02_p043-100_pp4.indd 99
Chapter 2 Understanding Ecosystems
99
12/3/09 1:23:44 PM
21.
Plants can and do obtain carbon, oxygen, and hydrogen directly from the environment in the form of
carbon dioxide and water, which they use for photosynthesis. However, plants can not obtain nitrogen
directly from the atmosphere. Instead, plants rely largely on nitrogen-fixing bacteria in the soil to take in
nitrogen gas and change it into forms that are then available for uptake by plants.
22.
Legumes have a symbiotic relationship with nitrogen-fixing bacteria that live in their root nodules. The
bacteria remove nitrogen from the air and change it into forms that can be used by plants. Some of the
nitrogen will remain in the soil and will be available for the corn crop.
23.
Sample answer: Plot all the data on the same graph versus time in years. Look for correlations between
precipitation and the levels of each water source. Look for correlations between water usage and supply.
Try to determine if temperature changes affect water supplies by changing the evaporation rate.
24. (a)
Sample answer: Humans can survive over a wider range of temperature than most animal species. Few
animals live at both the equator and inside the Arctic Circle.
(b)
Sample answer: Three abiotic factors required by humans are temperature, precipitation, and nutrients
in the environment. Optimum ranges of these factors for humans are approximately 60–80 °F,
35–50 inches of precipitation, and nutrient-rich soil.
(c)
Sample answer: People whose farmland is turning to desert are at the edge of the survival range in
terms of their need for fertile soil. Homeless people in Ontario live near the edge of the survival range
in terms of temperature.
25. (a)
(b)
Sample answer: Vegetation is a biotic factor that differs in the two biomes because the trees are
different. Also, different species of animals live in each biome.
Sample answer: Temperature is an abiotic factor that is different in the two biomes because they are
located in different ranges of latitudes. Also, the amount of rainfall in each biome is different because
the boreal forest gets much less rainfall than the deciduous forest.
26. (a)
Sample answer: The relationship between bees and flowering plants is one example of mutualism. Bees
receive nutrition when feeding on nectar from the plant’s flowers and the plant receives assistance with
reproduction when the bees spread its pollen.
(b)
Sample answer: The nesting of birds in trees may be described as an example of commensalism. Birds
build nests in trees to protect their eggs and young, but the trees may receive neither harm nor benefit.
100
Unit B: Sustainable Ecosystems
55219_02_ch02_p043-100_pp4.indd 100
NEL
12/3/09 1:23:45 PM