CHAPTER
3
Review
SUGGESTED ANSWERS
WHAT DO YOU REMEMBER?
1. (a)
services; (b) secondary; (c) rainforests; (d) risk; (e) habitat fragmentation; (f) habitat; (g) invasive
2. (a)
iii; (b) iv; (c) ii; (d) v; (e) i
3. (a)
(b)
4. (a)
5.
Tropical rainforest
Near the equator in countries such as Brazil, Malaysia, and Congo
Sample answer: As rivers and lakes become more acidic, plankton, which are at the bottom of the food
web, decline in numbers. The animals that depend on them also directly decline.
(b)
Sample answer: Acid precipitation depletes soil nutrients, leading to slower and weaker growth by
plants.
(c)
Sample answer: Sea birds and mammals that come in contact with oil spills will die of starvation,
poisoning or hypothermia.
(d)
Sample answer: Plastic trash floats and lasts a long time, forming huge floating “garbage patches”
in the ocean that kill marine animals.
Floating oil can be skimmed or vacuumed up. In bioremediation, microbes feed on the oil, breaking
it down. Floating oil can be burned (creating air pollution). Detergents can be used to disperse the oil,
breaking it into small drops.
WHAT DO YOU UNDERSTAND?
6. (a) cultural service, (b)
(g) product
7. (a)
8. (a)
(b)
product, (c) other service, (d) product, (e) cultural service, (f) other service,
v; (b) iv; (c) i; (d) ii; (e) iii
Sample answer: food storage container, juice bottle, shampoo bottle, medicine bottle, sandwich bag,
shopping bag, calculator, swim goggles, dog toy, music CD container, inkjet printer
Sample answer:
Often reused: food storage container, shopping bag, calculator, swim goggles, dog toy, music CD
container, inkjet printer
Usually recycled: juice bottle, shampoo bottle
Placed in the garbage: medicine bottle, sandwich bag
Discarded as litter: none
9.
Sample answer: Aboriginal peoples made things from natural ingredients (such as wood, bone, and plant
fibre), which decomposed or broke down when they were discarded. Also, Aboriginal communities had
relatively small populations, so there was less waste to dispose of.
10.
The loggerhead shrike is threatened by habitat loss. Over the past 50 years, it has lost its nesting habitat.
The population reached a low of 17 breeding pairs in Ontario in 1997.
11.
Sample answer: There is still habitat loss occurring in parts of Ontario. We contribute to habitat loss in
other parts of the world when we purchase products that contributed to the clearing or damage to habitat.
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12.
Biological control uses intentionally introduced organisms to control the invasive species. Mechanical
control includes using physical barriers or removal by cutting down, burning, or even by hand. Chemical
control is the most common method. Pesticides can be used to kill invasive species but they kill other
species as well
SOLVE A PROBLEM
13. (a)
Sample answer: The early food web is more complex, with more animals and more connections. It has
a top level of predators. The later food web is simpler, with only two levels: plants and herbivores.
(b)
Sample answer: I think removing the top predators probably led to an increase in the populations of
the three herbivores (white-tailed deer, moose, and beaver), which probably led to reductions in the
plant populations they fed on.
(c)
Sample answer: No, I do not think an overpopulation of white-tailed deer and beaver is surprising,
because their natural predators have been extirpated. The only limit to their populations is availability
of food sources and human hunters.
(d)
Sample answer: Lyme disease is likely to spread faster because deer populations are now larger—so it
is easier for the wood ticks to be successful and their numbers will increase. Also I would predict that
the deer would need to compete more for food sources and therefore would have to travel more. This
would spread the ticks over a greater range.
CREATE AND EVALUATE
14.
Sample answer: I think hunting and fishing should be allowed because humans now have to fulfill the role
of the top predators that we extirpated from many ecosystems. For example, if humans do not control
the white-tailed deer population, they will overpopulate and damage plant communities. I think hunting
and fishing for food is more justified than doing so just for entertainment. Perhaps people that depend on
hunting and fishing as a food source should be allowed higher limits.
15.
Sample answer: People living in modern society cannot entirely avoid contributing to air pollution, even
when enjoying nature. They should, however, just try to reduce the amount of air pollution they create (for
example, by driving fuel-efficient cars). They should participate more in recreational activities that are less
damaging such as cross country skiing instead of snowmobiling, or canoeing instead of power-boating.
16.
Sample answer: Letting fires burn in parks is a good idea because fires are crucial to the long-term
sustainability of forest ecosystems. Fires lead to secondary succession, which is necessary for the survival
of many species. However, it might be necessary to prevent a fire if it is damaging very rare habitat or
threatening a population of an endangered species.
REFLECT ON YOUR LEARNING
17. (a)
(b)
18.
Answers will vary. Students may have suspected there are perhaps a few dozen or fewer.
Sample answer: I would look up information on websites such as those of COSEWIC and RENEW.
Sample answer: I am more aware of how valuable ecosystems are to my own life. I think I will spend more
time hiking. I will also pay closer attention to ecological issues in the news. I may volunteer to help with
monitoring species diversity.
WEB CONNECTIONS
19. (a)
Sample answer: Because the islands formed several million years ago, they have remained isolated from
mainland South America, so plant and animal species have evolved to form many new species that can
only be found on these islands.
(b)
Sample answer: Tourism has greatly increased since the 1960s, which has led to population growth and
the building of much infrastructure. So in the inhabited areas, the impact of tourism has not really
been controlled. But in the visitor areas and protected areas, tourists are required to stay on trails, use
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guides, and follow set itineraries. In some locations the number of visitors is limited. Visitors are also
required to pay entrance fees, which go towards conservation projects.
(c)
20.
Sample answer: goats, rats, cats, pigs, dogs, fire ants, and two species of wasps
(a) In Prince Edward Island Canada Summerside Three Oaks High School Environmental Club
(b)
The club participated in the Canon Envirothon. The Canon Envirothon has high school students
from throughout North America compete in their knowledge of environmental issues. In 2009, the
topic was Biodiversity in a Changing World, in which students analyzed short and long-term impacts
of human activities on genes, species, and ecosystems relative to how each may influence or directly
impact their future.
(c)
Students did very well in the competition and used the opportunity to make connections for science
projects and education in college and beyond
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