Practice Exam 3 - Environmental Science - page 311

88. A The increasing spread of disease and death among the young could cause birth rates to increase and
return to a rate similar to that seen in the pre-industrial stage of demographic transition. Historically, if
death rates for the young start increasing, parents will start having more children to compensate for the
loss.
89. D President Theodore Roosevelt was responsible for the creation of the National Wildlife Refuge Sys-
tem in 1903, which aims to preserve wildlife, populations, habitat, and land.
90. D Wetlands are valuable ecosystems because they provide many ecosystem services such as filtering
pollutants, recharging aquifers, and flood reduction.
91. E One benefit of organic agriculture is its use of natural as opposed to synthetic inputs. Natural inputs
have less impact on the environment, allowing native ecosystems to continue thriving in the absence of
man-made chemicals.
92. A The United Nations Environmental Program aims to protect biodiversity and conserve natural re-
sources on a global level, including an initiative to encourage the planting of indigenous trees. The or-
ganization helps nations find ways to address and solve environmental issues.
93. C Oil and biomass are the most widely-used forms of energy in developing nations. Biomass is widely
used because it is relatively easy and inexpensive to attain. Often, people use biomass in the form of
crop residue and animal manure from their own property. Oil is becoming more commonly used in de-
veloping countries as they become industrialized and not only need but can acquire oil.
94. B PBDEs are commonly used as fire retardants in many products. Unfortunately, they can act as endo-
crine disruptors in humans and other organisms.
95. C POPs are a group of chemicals that bioaccumulate, persist, and travel long distances.
96. A Lead is a heavy metal, and heavy metals can have negative effects on the nervous system.
97. A Genetic pollution is the unintended spread of altered genes from genetically modified organisms to
natural organisms. Genetic pollution is becoming more common as the use of GMOs is becoming more
common.
98. C The main reason for the reduction in water volume of the Aral Sea is excessive water withdrawal for
use in irrigation. The region is also hot, dry, and prone to drought, making the replenishment of with-
drawn water difficult.
99. E The process of remediation would be used to clean up soil and groundwater contaminated by a leak-
ing underground tank. Possible remediation techniques include excavation, extraction, bioremediation,
aeration, phyotoremediation, and thermal remediation.
100. B Kudzu is an invasive species because it is fast growing, hard to kill, and smothers other types of ve-
getation. It is not originally native to North America as it is indigenous to Asia.
Section II: Free-Response Questions
1. This question is worth a maximum of 10 points, as follows:
A. Discuss how habitat fragmentation can impact the genetic diversity of a species. (2 points maximum)
• 1 point: It limits gene interchange through a population.
• 1 point: It can lead to inbreeding depression.
• 1 point: There is increased susceptibility to disease.