MIDTERM EXAM STUDY GUIDE
This study guide includes questions and problems related to Chapters 1 – 6 of your Environmental Science textbook. Respond to each item in detail in preparation for your Midterm Exam.
Chapter 1: Science and the Environment
1. Identify and define five major fields of environmental science. Provide an example of one subfield within each major filed along with a description. (see p. 7)

2. Describe the major human activities in each of the following periods and determine how those actions had a significant effect on the environment. (see pp. 9 – 11)
a. hunter-gatherer: Hunter-gatherers obtained food by collecting plants, hunting wild animals, and scavenging the remains of dead animals. They burned prairies because it prevented tree growth and made it easier for them to hunt. Such methods caused overhunting, which eventually led to the disappearance of some large mammals.
b. agricultural revolution: The agricultural revolution was a period in which humans began growing, breeding, and caring for plants and animals that were used for food, clothing, housing, transportation, and other purposes. As human populations grew, grasslands, forests, and wetlands were destroyed and replaced with farmland.
c. industrial revolution: During the industrial revolution, humans greatly increased their usage of machines and fossil fuels, which caused populations to grow in urban areas. Lifestyle changes caused by the industrial revolution introduced a new set of related environmental problems – many of which are still being addressed today.
3. Name and describe the three main categories of environmental problems. Provide one example of how human actions contribute to each problem. (see pp. 14 – 15)
a. Resource depletion occurs when a large fraction of a particular resource has been used up. For example, humans cause deforestation by cutting down and harvesting trees faster than they can grow.
b. Pollution is an undesired change in air, water, or soil that adversely affects the health, survival, or activities of humans or other organisms. Humans pollute the air by driving their automobiles. The car exhaust releases carbon dioxide into the atmosphere.
c. Loss of biodiversity refers to the extinction of the many species on Earth. Humans contribute to this problem in many ways such as polluting the environments of these species and destroying their habitats.
4. Explain three major differences between developed countries and developing countries. Give one example of each type of country. (see p. 18) Developed countries have higher average incomes, slower population growth, and diverse industrial economics with stronger social support systems. Developing countries, on the other hand, have lower average incomes, rapid population growth, and simple, agricultural-based economies. The U.S. is a developed country while India may be considered a developing country.
5. Compare the distribution of resources of developed countries to that of developing countries in terms of percentages. With respect to population sizes, do you believe these current consumption trends are fair? Support your response. (see p. 19) Developed countries use about 75% of the world’s resources, but make up only about 20% of the population.
Chapter 2: Tools of Environmental Science
6. Thoroughly describe the two essential characteristics of a good scientific experiment. Be sure to compare the types of groups used in such an experiment. (see p. 35) Good experiments test for a single variable and use a control, allowing us to pinpoint cause-and-effect relationships. The variable is the factor of interest. To test the variable, scientists usually use two groups. A group that receives experimental treatment is called the experimental group. A group that does not receive the experimental treatment is called the control group.
Month Cost of Bill (in dollars)
December $46
January $58
February $70
March $82
April $94
May $106
7. Using the data in the table above:
a. Provide a general hypothesis based on your observation of the student’s cell phone bill. (see p. 34) If the current trend continues, the student’s cell phone bill will increase for the month of April and be even higher in the month of May.
b. Predict the student’s actual bill for the months of April and May by filling in the blank spaces in the table. (notice the bill increase by $12 from one month to the next)
c. What type of scientific model did you use to make this prediction? (see p. 46) mathematical model
8. A student rolls a six-sided die 30 times and obtains the following results. Use this piece of information and the data table below to answer the following questions.
Numbers on the Die How Many Times the Die Landed on this Number
1 2
2 6
3 3
4 6
5 10
6 3
a. What is the sample size used in this experiment? (see p. 42) The sample size is 30 rolls of the die.
b. Under normal conditions, what is the probability of rolling any given number on the die? (see p. 42) 0.17 (or 1/6 or 17%)
c. According to the experimental data, what is the probability of rolling a “2”? (see p. 42) 0.2 (or 6/30 or 20%)
d. How could the student increase the accuracy of the experimental results in this experiment? (see p. 42) The sample size is too small, so the student should roll the die more times to increase the accuracy of the experiment.
9. Describe the four steps involved in a good decision-making model. (see p. 47) A good decision-making model involves gathering information, considering values, and exploring consequences before making a decision.
Chapter 3: The Dynamic Earth
10. Name and briefly describe the major systems of the Earth. (see p. 63) The geosphere is the solid part of the Earth, which extends from the core to the outer surface. The hydrosphere is the layer of water below, on, and near the Earth’s surface. The atmosphere is the layer of air we breather just above the Earth’s surface. The biosphere is the part layer on Earth where life exists and includes parts of the geosphere, hydrosphere, and atmosphere.
11. In general, describe the three ways in which tectonic plates interact with each other. What kind of natural disaster usually results from this type of interaction? Is it likely that New Jersey would experience such a disaster? (see p. 66 or your Earthquake Webquest Assignments) Tectonic plates can move away from one another (divergent boundary), move towards each other (convergent boundary), or slip past one another (lateral slipping boundary). Earthquakes usually result from this type of movement. Volcanic eruptions are sometimes triggered as well. It is not likely that NJ would experience such a disaster because it is not near a tectonic plate boundary; however, it is possible on rare occasions.
12. Describe both the local and global effects of a massive volcanic eruption. (see p. 69) Locally, volcanic eruptions can be devastating to local economies and can cause great human loss. Clouds of hot ash, dust, and gases can flow down the slope of a volcano at speeds of up to 200 km/h and sear everything in their path. During an eruption, volcanic ash can mix with water and produce a mudflow. In addition, ash that falls to the ground can cause buildings to collapse under its weight, bury crops, and damage the engines of vehicles. Volcanic ash may also cause breathing difficulties. Globally, major volcanic eruptions can change Earth’s climate for several years. In large eruptions, clouds of volcanic ash and sulfur-rich gases may reach the upper atmosphere. As the ash and gases spread across the planet, they can reduce the amount of sunlight that reaches the Earth’s surface. This reduction in sunlight can cause a drop in the average global surface temperature.
13. In terms of gases and percentages, briefly describe the composition of Earth’s atmosphere. (see p. 71) Earth’s atmosphere is made up of about 78% percent nitrogen and 21% oxygen. The remaining 1% consists of argon, carbon dioxide, methane, and water vapor.
14. Describe the four layers of the atmosphere in terms of temperature, pressure, and altitude. (see pp. 72 – 73)

15. Name and describe the three ways in which energy from the sun is transferred in Earth’s atmosphere. (see p. 74) Radiation is the transfer of energy across space in the atmosphere. Conduction is the flow of heat from a warmer object to a cooler object when the objects are in physical contact. Convection is the transfer of heat by air currents.
16. Explain how a car provides an example of the greenhouse effect on a hot, sunny day. (see p. 76) As sunlight passes through a car window radiant energy is absorbed and turns into heat. The heat is circulated inside the car, but the glass windows prevent most of the heat from escaping as the temperature gradually increases. The Earth’s atmosphere behaves similar to the car’s windows in this example.
17. Name and describe the three main phases of the water cycle. (see p. 77) Evaporation is the process by which water is heated by the sun and rises into the atmosphere as water vapor. During condensation, water vapor forms water droplets and clouds. Precipitation occurs when water droplets become heavy enough to fall as rain from clouds. Precipitation can also be in the form of snow, hail, or sleet.
18. Define the term salinity and name the two main elements that make ocean water salty. (see p. 80) Salinity is the term used to describe the concentration of all salts dissolved in a body of water. In the ocean, the two main elements that make the water salty are chlorine and sodium.
Chapter 4: The Organization of Life
19. Name and describe the two types of factors that make up an ecosystem. Provide one example of each factor. (see p. 100) Ecosystems are made up of living things (biotic factors) and nonliving things (abiotic factors). Examples of biotic factors include plant and animal species. Examples of abiotic factors include air, water, rocks, and soil.
20. Compare and contrast organisms, populations, and communities. Provide one example of each. (see pp. 101 – 102) An organism is an individual living thing, such as a frog. A population includes all the members of the same species that live in one place at the same time, such as the frogs that live in and around a lake. A community is a group of different species living in the same place and interacting with each other, such as all the plants and animals that live in and around the lake.
21. Describe the process in which useful adaptations are passed down from one generation to the next. What is this process called? Name an organism of your choosing and give an example an inherited adaptation. (see pp. 103 – 105) Useful adaptations are genetically inherited through reproduction by natural selection. As more members of the species continue inherit the traits from one generation to the next, the process becomes known as evolution. For example, some species of deer have evolved thick fur enabling them to survive in colder climates.
22. Complete the table below with the six kingdoms of life. Provide at least two characteristics and two examples for each kingdom. (see p. 108)

Chapter 5: How Ecosystems Work
23. Describe the process of photosynthesis and explain how it is involved in the carbon cycle. (see pp. 125 and 132) Photosynthesis is the process in which plants use sunlight to make sugar molecules called carbohydrates. Plants also absorb carbon dioxide from the atmosphere, which is related to the carbon cycle.
24. Describe the four main types of consumers in an ecosystem and provide one example of each. (see p. 127)

25. Describe the process of cellular respiration and explain how it is related to the carbon cycle. (see pp. 128 and 132) Cellular respiration is the process in which organisms break down food to produce energy. In addition, the release of carbon dioxide, as well as water, relate this process to the carbon cycle.
26. What is the difference between a food chain and a food web? (see p. 130) A food chain is a sequence in which energy is transferred from one organism to the next as each organism eats another organism. A food web shows many feeding relationships that are possible in an ecosystem.
27. Explain why an energy pyramid is a good representation of the relative amount of energy and the number of species available at each trophic level. (see p. 131) An energy pyramid gets smaller as you view it from the bottom to the top. Similarly, the amount of energy and the number of species is greatest at the bottom of the pyramid. Both the amount of energy and the number of organisms decrease as you move up through each trophic level.
28. Define the term pioneer species and provide one example. (see pp. 138 and 141) Pioneer species are the first organisms to colonize any newly available area and begin the process of ecological succession. Lichen, mosses, and weeds are examples of pioneer species.
29. Define the term ecological succession and name the point at which the most dominant species is present. (see pp. 137 and 138) Ecological succession is a gradual process of change and replacement of some or all of the species in a community. The most dominant species becomes present at the final stage known as a climax community, which remains the same if left undisturbed.
Chapter 6: Biomes
30. Briefly describe each of the biomes listed below:
a. Tropical rain forest: consistently humid and warm all year round; located in a belt near the equator (30° north or south latitude); contains the largest variety of species of all the biomes
b. Temperate rain forest: high precipitation and humidity with moderate temperatures; located in parts of North America, Australia, and New Zealand; vegetation ranges from large trees, to lush ferns, to evergreens
c. Temperate deciduous forest: experiences seasonal fluctuations in weather patterns; located between 30° and 50° north latitude; vegetation varies with the season; we live in this biome
d. Taiga: stretches across a broad band in the northern hemisphere just below the Arctic Circle; winter are long; vegetation is characterized by tall, woody trees
e. Savanna: a tropical biome dominated by grasses, shrubs, and small trees which support a wide variety of herbivores; rainfall occurs for only a few months out of the year and while temperatures remain relatively high and constant
f. Temperate grassland: receives moderate rainfall, but not enough for large trees to grow; temperatures are seasonal; vegetation consists mostly of grasses, wildflowers, and shrubs
g. Chaparral: coastal biome with a relatively stable temperature year-round; there is little to no rain during the summer months; most chaparral plants are low-lying, evergreen shrubs and small tress that grow in dense patches
h. Desert: the driest biome; experiences highly scattered vegetation and very little precipitation; in extreme cases there may be no rainfall or vegetation at all; plants and animals have special adaptations for obtaining and conserving water
i. Tundra: located in the northern Arctic region; winters are cold and dry prohibiting the growth of large trees; deep layers of soil are permanently frozen (permafrost); mosses and lichen cover much of the landscape; other plants have wide shallow roots to anchor themselves in the thin layer of topsoil that thaws during the summer season
Chapter 7: Aquatic Ecosystems

31. Refer to the graph above. Respond to each item below.
a. How does oxygen concentration vary with depth of water in a noneutrophic lake? How does it vary in the eutrophic lake? A noneutrophic lake shows a slight decrease in oxygen concentration as water deepens. In contrast, the oxygen content of a eutrophic lake declines sharply with depth, especially within the first six meters.
b. Based on oxygen content, which lake would probably have a greater number of species? Explain. (p. 136 and 187) The higher oxygen content of the noneutrophic lake supports greater species diversity.
c. Make a bar graph that displays the approximate oxygen concentration of both lakes at a depth of 10 meters.

d. State the approximate oxygen concentration of both lakes at a depth of 10 meters. How many times greater is the oxygen level in the noneutrophic lake compared to the eutrophic lake? Noneutrophic lake: 8 mg/L; eutrophic lake: approximately 0.25 mg/L. At a depth of 10 meters, oxygen levels are about 30 times greater in the noneutrophic lake.
e. Suggest at least two actions that can be taken to reverse eutrophication in lakes. Provide reasons to support your suggestions. Actions can be taken to control or reduce the amount of runoff that enters lakes from farms and factories. This can be accomplished in a number of ways, including using less fertilizer on crops, building better sewage systems, or enforcing existing environmental laws that regulate factory waste discharge.