Ecology

Objectives

Quiz 1:

1. Identify the different levels of organization (above the level of individual).

2. Define habitat and niche.

3. Explain how energy flows through an ecosystem, and be able to use an energy pyramid to illustrate this.

4. Use a food web to identify and distinguish producers, consumers and decomposers.

5. Explain the transfer of energy through the trophic levels of a food web.

6. Use a food web to determine the effects on other populations of a disruption to one member of the web, whether due to natural causes, changes in climate, human activity, or introduction of a non-native species.

Quiz 2:

7. Explain how birth, death, immigration, and emigration influence a population size.

8. Draw and explain exponential and logistic growth of populations.

9. Explain carrying capacity and identify limiting (density-dependent and density-independent) factors that determine its value.

10. Describe and give examples of predation, competition, and the three types of symbiotic relationships.

11. Explain how community succession describes changes from pioneer species to climax community, and distinguish between primary and secondary succession.

12. Explain the impacts of invasive species, climate change, habitat fragmentation, pollution, and overharvesting on biodiversity and ecosystems.

13. Explain how carbon cycles between biotic and abiotic in an ecosystem.

Vocabulary

Quiz 1:

10% Rule

Abiotic factor

Biomass

Biome

Biotic factor

Carnivore

Community

Consumer

Decomposer

Detritivore

Ecology

Ecosystem

Energy

Food chain

Food web

Generalist

Habitat

Herbivore

Niche (Fundamental and Realized)

Omnivore

Population

Primary consumer

Producer or primary producer

Quaternary consumer

Secondary consumer

Tertiary consumer

Trophic level

Quiz 2:

Atmosphere

Biogeochemical cycle

Biodiversity

Biosphere

Carbon cycle

Biomass
Combustion
Decomposition
Fossil fuel
Hydrocarbon

Carrying capacity (K)

Climate change

Climax community

Commensalism

Competition

Density-dependent limiting factor

Density-independent limiting factor

Exponential growth

Geosphere

Global warming

Greenhouse gas

Growth rate (r)

Birth rate, death rate, immigration rate, emigration rate

Habitat fragmentation

Invasive species

Keystone species

Limiting factor

Logistic growth

Mutualism

Ocean acidification

Overharvesting

Parasitism

Pioneer species

Pollution

Predation

Succession

Primary succession
Secondary succession

Symbiosis

Textbook Reference

Quiz 1:

12.1: Ecology affects your life and our broader society

12.2: Ecology is the scientific study of organisms in their environments

12.3: Ecosystems include a variety of abiotic factors

12.8: Food webs describe multiple trophic structures

12.14: Energy is lost as it moves through trophic levels

Quiz 2:

12.4: Populations vary in age structure, survivorship, density, and dispersion

12.5: Growth models can predict changes in population size

12.6: Human population growth has been exponential

12.7: Interactions between species play important roles in communities

12.9: Several factors affect species diversity

12.10: Invasive species can disrupt ecosystems

12.11: Biodiversity is measured on many levels

12.15: Elements cycle through the biosphere

12.17: People cause many ecological problems

12.18: People can solve ecological problems

12.19: Human activity is causing a rise in greenhouse gases

Relevant Files

Ecology Honors

Sample MCAS Questions

Quiz 1:

1. A simple food web is shown below.

Which of the following changes is most likely to occur if the sparrow population decreases?

A. the fox population decreases

B. the hawk population increases

C. the grasshopper population competes less with the preying mantis population

D. hawks and foxes prey more heavily on grasshoppers

2. Part of a food web for a marine kelp forest is shown.

Which of the following statements correctly describes the transfer of energy that initially enters this system?

A. The sea urchin gets energy from the sea otter.

B. The shark receives most of the energy that enters the ecosystem.

C. The crab transfers less energy to the next trophic level than does the rockfish.

D. The seaweed converts energy into a form that can be used by other organisms.

3. The diagram below represents a food web.

Which of the following are consumers in this ecosystem?

A. apples

B. clover

C. mice

D. nuts

4. The diagram below shows a food web for an ecosystem.

a. Identify the producers and the consumers in this food web.

b. In this ecosystem, is more energy available to the field mouse population from eating spiders or from eating oats? Explain your answer.

5. A partial food web for a coastal ecosystem is shown below.

Which of the following organisms in this food web obtains energy from both producers and consumers?

A. anchovy

B. mysid shrimp

C. weakfish

D. sand shrimp

Questions 6-8

A partial food web for organisms in Yellowstone National Park is shown below.

6. Which of the following organisms is a secondary consumer in this food web?

A. yellow-bellied marmot

B. strawberry plant

C. least chipmunk

D. king bolete

7. Which of the following releases oxygen into this food web ecosystem?

A. elk respiration

B. Idaho fescue photosynthesis

C. sweet cicely root decomposition

D. migratory grasshopper reproduction

8. Assume the elk population in Yellowstone National Park increases. Discuss how this increase in elk will most likely affect each of the following populations:

Idaho fescue
Migratory grasshopper
Grizzly bear

Be sure to include specific reasons to support each of your responses.

9. Which of the following lists identifies organisms that are producers in food webs?

A. Algae, ferns, sunflowers

B. Mushrooms, bacteria, earthworms

C. Termites, red foxes, shrews

D. Woodpeckers, cardinals, grasshoppers

10. Which of the following lemurs would be classified as a secondary consumer?

A. A mouse lemur eating insects

B. A Verreaux's sifaka eating leaves

C. A ring-tailed lemur eating fruits

D. A red-bellied lemur eating flowers

11. The graph below shows the levels of acidity that different kinds of freshwater fish can tolerate. Low pH values mean the water is more acidic.

Based on the data, which of the following fish would most likely experience the largest population declines due to acid rain pollution?

A. Brown trout

B. Smallmouth bass

C. Fathead minnow

D. Yellow perch

12. A marine food web is shown below.

Which of the following diagrams correctly represents an energy pyramid from this web? Options are given in the order A, B, C, D.

13. A small part of a food web for a forest ecosystem is shown below.

a. Classify each of the five organisms in the food web as a producer, a primary consumer, a secondary consumer, or a tertiary consumer.

b. Identify the type of ecological relationship between salamanders and birds in this food web.

c. Suppose there is a significant decrease in the bird population. Based on the relationships in the food web, explain why it would be difficult for ecologists to predict what would happen to the size of the salamander population.

14. A part of a desert food web is diagrammed below.

Which of the following will most likely result if all of the primary consumers are removed from this ecosystem?

A. Prairie rattlesnakes will become herbivores.

B. Golden eagle and kit fox populations will decrease.

C. Sagebrush grasshoppers will consume soil bacteria.

D. Silk grass and sand sagebrush populations will decrease.

15. A caterpillar eats an oak leaf. Which of the following best describes the energy transfer in this situation?

A. Both the caterpillar and the leaf gain energy.

B. Energy is transferred from the leaf to the caterpillar.

C. Decomposers in the leaf obtain energy from the caterpillar.

D. The oak tree gains energy when the caterpillar eats the leaf.

16. Which of the following would most likely happen if grasses and shrubs were removed from a rural Massachusetts ecosystem?

A. There would be an increase in consumers in the ecosystem.

B. There would be an increase of photosynthesis in the ecosystem.

C. There would be a decrease in food energy produced by the ecosystem.

D. There would be a decrease of carbon dioxide available to the ecosystem.

17. A food web is shown below.

In this food web, the trophic level with the least energy includes which of the following organisms?

A. Giant white clam

B. Tube worm

C. Sulfur bacteria

D. Vent crab

Quiz 2:

18. Which of the following is ALWAYS a result of immigration into a population?

A. New individuals are added to the population.

B. Some individuals are forced to leave the population.

C. The survival rate of the individuals in the population increases.

D. The genetic diversity among the individuals in the population decreases.

19. Black terns are a species of bird living in marshes, ponds, and marshy lakes. They feed on insects, fish, and crustaceans. They usually make their nests on loose, floating vegetation.

Which of the following environmental changes would most likely decrease the size of the black tern population?

A. A competing bird population decreases in size.

B. Fish species have a more successful breeding season than usual.

C. A new plant species invades the environment and creates a dense cover of vegetation.

D. Insect larvae experience lower than average rates of predation and survive to adulthood.

20. Carbon moves through the environment via the carbon cycle. Some carbon exists as carbon dioxide in the atmosphere. Scientists believe that increased amounts of atmospheric carbon dioxide significantly contribute to the greenhouse effect and global warming.

a. Identify two carbon cycle processes that add carbon dioxide to the atmosphere.

b. Identify one carbon cycle process that removes carbon dioxide from the atmosphere.

c. Describe one action that humans could take to reduce levels of carbon dioxide in the atmosphere. Explain how the action would reduce carbon dioxide levels.

21. Which of the following processes releases primarily oxygen into the atmosphere?

A. combustion

B. osmosis

C. photosynthesis

D. respiration

22. Approximately 250 million years ago, over 90% of species living in the oceans became extinct. Which of the following conditions most likely contributed to this mass extinction?

A. changes in global climate

B. evolution of a new parasite species

C. mutation of species' DNA sequences

D. increases in the rates of photosynthesis

23. The growth of most plants is limited by the amount of nitrogen available. Which of the following effects does low nitrogen availability most likely have on the carbon cycle?

A. More carbon dioxide is taken up by plants.

B. Carbon dioxide is trapped in the soil around plants.

C. Less carbon dioxide is removed from the atmosphere.

D. Carbon dioxide is converted to carbonates by bacteria.

24. Populations of Caribbean coral have decreased significantly over the past 30 years due to disease. Which of the following is most likely a major factor leading to the increased amount of disease in the coral?

A. Symbiotic algae are living in the coral cells

B. Several different species of fish live on the coral reefs

C. Levels of spawning have decreased and lowered reproductive rates.

D. Water temperatures have increased and favored the growth of microorganisms.

25. There is a limit to how large any given population can grow. Which of the following statements best explains why a population must eventually stop growing?

A. A low female-to-male ratio develops in the population as it grows.

B. Old individuals outnumber juveniles in the population as it grows.

C. The resources available are fully used by the population as it grows.

D. Natural selection changes the gene pool of the population as it grows.

26. On remote islands, immigration and emigration usually do not have a large effect on population sizes. A bird population on a remote island remains at a relatively constant size year after year.

Which of the following most likely describes the birth rate and death rate for this population?

A. Birthrate and death rate are both zero.

B. Birth rate and death rate are close to equal.

C. Birth rate is significantly less than death rate.

D. Birth rate is significantly greater than death rate.

27. Kilauea is a Hawaiian volcano that erupted in 1959, destroying vegetation and animal life over an area of 5 million square meters. Before the eruption, many organisms lived on the volcano in a rainforest community. The rainforest was dominated by ohia trees and two species of tree ferns. Small trees, tall shrubs, and herbaceous plants (plants lacking woody tissues) were also present.

After the eruption, scientists closely monitored the area to track the recolonization of the devastated habitat. Scientists did not find any organisms living in this area for the first six months following the eruption. The table below shows the changes in one localized area that was covered by a massive amount of lava rock with many cracks and crevices. Despite the colonization of the area by several different types of organisms by year 9, the overall cover the habitat was so low that the surface still looked barren.

Type of Organism

% of Community 6 Months After Eruption

% of Community 1 Year After Eruption

% of Community 3 Years After Eruption

% of Community 7 Years After Eruption

% of Community 9 Years After Eruption

Algae

Mosses

Ferns

Lichens

Seed plants

Based on the data, most of the pioneer species in this area were which of the following organisms?

A. Algae

B. Mosses

C. Ferns

D. Plants

28. A hurricane sweeps across a small Caribbean island, killing 50% of the herbivore species on the island. Which of the following is the most immediate result?

A. a reduction in biodiversity

B. an acceleration of the carbon cycle

C. an increase in predator populations

D. a decline in decomposer populations

29. A graph of atmospheric carbon dioxide concentration over time is shown below.

Scientists are investigating the cause of the large increase in atmospheric carbon dioxide concentration since about 1800. Which of the following provides the best explanation for the increase?

A. eruptions of large volcanoes

B. use of fossil fuels by humans

C. natural fluctuations of climate

D. photosynthesis by phytoplankton

30. Part of a tundra food web is shown below.

Which of the following describes the relationship between the sedge and the arctic hare?

A. competition

B. host-parasite

C. mutualism

D. producer-consumer

31. A builder is proposing a new housing development in an area of western Massachusetts. Construction of the housing development will destroy wetland habitat in the area. Which of the following would be the most likely consequence of the wetland's destruction?

A. The wetland plant species would disperse to adjacent meadow habitats.

B. The populations of wetland animals would be unable to survive in that area.

C. The wetland animal species would survive by interbreeding with non-wetland animal species.

D. The populations of wetland plants would evolve to disperse seeds by wind rather than by water.

32. Which of the following relationships is an example of mutualism?

A. A lion eats a gazelle.

B. A viruses uses both a bird and a horse as hosts.

C. A bacterium breaks down dead plant materials.

D. A bird eats food particles from a crocodile's teeth.

33. The graph below shows changes in the birth rate and death rate for a large population of deer over a 20-year study period.

a. Describe and explain two factors that can affect the birth rate in the deer population.

b. Describe and explain two factors that can affect the death rate in the deer population.

c. Identify one time period on the graph during which the deer population was increasing. Explain your answer.

34. Which of the following human activities reduces biodiversity?

A. Prohibiting hunting in wildlife preserves

B. Taking tissue samples from members of endangered species

C. Planting only native grass species to prevent erosion beside highways

D. Planting only red pine trees to replace native hardwood forests cut for lumber

35. Leaves fall from deciduous trees in autumn. The carbon in these leaves is returned to the atmosphere through which of the following processes?

A. condensation

B. decomposition

C. photosynthesis

D. transpiration

36. A population of flat-tailed horned lizards was found in a geographically isolated area. In 2002, the size of the population was about 25,500. In 2004, the size of the population was about 32,800. Which of the following statements explains the change in the size of the lizard population from 2002 to 2004?

A. The birth rate was greater than the death rate.

B. The emigration rate was greater than the birth rate.

C. The death rate was greater than the immigration rate.

D. The emigration rate was greater than the immigration rate.

37. Air samples taken in Canada since 1986 show that atmospheric carbon dioxide concentration is higher on average in winter than in summer. Which of the following statements best explains the difference in carbon dioxide concentrations?

A. The rate of decomposition is slower in winter than in summer.

B. The greenhouse effect is more pronounced in winter than in summer.

C. The number of animals that are active is less in winter than in summer.

D. The amount of photosynthesis by plants is lower in winter than in summer.

38. The table below shows data on reproduction for mouse populations at various population densities.

Average number of Mice per Cubic Meter

Average Percent of Pregnant Females

Average Number of Mice Per Litter

58.3

6.2

118

49.4

5.7

350

51.0

5.6

1600

43.3

5.1

Based on the data, which of the following statements best describes an effect of population density on mouse populations?

A. High population density increases the birthrate.

B. High population density decreases the birthrate.

C. High population density increases the male to female ratio.

D. High population density increases the number of successful matings.

39. When spring and summer conditions are warm and rainy, mosquito populations often become quite large. Which of the following statements best helps to explain this relationship?

A. Mosquito larvae eat organic debris.

B. Adult male mosquitoes feed on plant nectar.

C. Mosquitoes are attracted to warm-blooded animals.

D. Female mosquitoes lay their eggs in pools of water.

40. Some species of penguins, such as chinstrap penguins, depend on open water for their survival. Other species of penguins, such as Adelie penguins, depend on ice. Over the last 20 years, the population size of chinstrap penguins has increased and the population size of Adelie penguins has decreased. Which of the following most likely caused these changes in population size?

A. an increase in landmass and shorelines

B. an increase in global air and water temperatures

C. a decrease in the number of leopard seal predators

D. a decrease in the length of time before chicks take to sea

Use the information below to answer questions 41-44.

Forest and wetland ecosystems in Canada and parts of the northern United States are home to moose, Alces alces. The illustration below shows a moose and some of the plants and other animals found in its typical habitat.

One serious problem for moose is a disease called moose brainworm. Effects of the disease include aimless walking in circles, poor coordination and balance, weakness, and paralysis of the legs. Many cases of the disease result in death. The disease is caused by a parasitic roundworm, Parelaphostrongylus tenius. The life cycle of this roundworm involves snails, white-tailed deer, and moose, as shown in the diagrams below. Of these organisms, only the moose gets sick from infection by the roundworm.

41. The moose belongs to which trophic level in an ecosystem?

A. producer

B. consumer

C. scavenger

D. decomposer

42. A correlation exists between the number of cases of moose brainworm disease and the density of the deer population. Which of the following statements gives the best explanation for this relationship?

A. High deer population density causes individual deer to reproduce more.

B. High deer population density speeds up the life cycle of the roundworm.

C. High deer population density attracts more moose to an area where they will become infected.

D. High deer population density results in more larvae-infected waste for snails to encounter in an area.

43. Which of the following has the least influence on the population size of the deer?

A. annual birthrate

B. amount of predation

C. roundworm parasites

D. emigration over winter

44. The introductory information describes one relationship between organisms in the illustration: parasitism. All the organisms pictured in this habitat interact in other ways as well.

a. Describe one example of competition between the organisms in the illustration. Name the organisms involved, describe their interaction, and explain why their interaction is considered competition.

b. Describe one example of commensalism between organisms in the illustration. Name the organisms involved, describe their interaction, and explain why their interaction is considered commensalism.

45. Every year, monarch butterflies from Canada and the United States spend the winter in central Mexico. The dry and mild climate in Mexico allows the monarch butterflies to survive the winter. One winter, a week of storms caused freezing temperatures and 43 cm of snow in Mexico. What was the most likely impact of these storms on the monarch butterflies?

A. Monarch butterflies died in large numbers.

B. Monarch butterflies immediately migrated back to the United States.

C. Monarch butterflies did not migrate from Canada and the United States the next year.

D. Monarch butterflies evolved several new adaptations to survive the winter in Mexico.

46. The size of a bird population increased by two percent in one year. Which of the following could have contributed to the population increase?

A. A decrease in the death rate of baby birds

B. An increase in the number of the birds' predators

C. An increase in the average number of parasites per bird

D. A decrease in the immigration of birds of the same species

47. When locust populations grow too large for an area, the individual locusts are crowded and food becomes scarce. In response to these conditions, some of the locusts leave the area and find a new habitat. Which of the following terms best applies to the response of the locusts that leave for the new habitat?

A. Commensalism

B. Emigration

C. Hibernation

D. Mutualism

48. In traditional landscaping, leaves are raked off the ground and bagged. In which of the following ways does this practice most significantly disrupt natural nutrient cycling?

A. It carries away microorganisms that can perform nitrogen fixation.

B. It reduces the rate of oxygen and carbon cycling via photosynthesis.

C. It prevents carbon, oxygen, and nitrogen from being returned to the soil.

D. It increases the amount of carbon dioxide that is released to the atmosphere.

49. In the past 100 years, levels of atmospheric carbon dioxide have increased as the result of the burning of fossil fuels. Other processes in the carbon cycle have absorbed some of the carbon released by this combustion. Which of the following most likely have absorbed excess carbon released by combustion?

A. animals

B. glaciers

C. plants

D. rocks

50. The graph below shows changes in the sizes of four animal populations over a 16-year period.

In which population was birthrate most likely greater than death rate from year 8 to year 12?

A. population 1

B. population 2

C. population 3

D. population 4

51. The northern spotted owl is listed under the Endangered Species Act as a threatened species in its primary range of Washington, Oregon, and California. Which of the following most likely contributed to the northern spotted owl’s population decline?

A. increases in rodent populations

B. loss of trees from forest habitat

C. prevention of wildfires in forests

D. decreases in mountain lion populations

52. Which of the following explains why elements, such as carbon and oxygen, that are used in organic molecules are not permanently removed from the environment?

A. They are replenished by sunlight.

B. They are cycled through the ecosystem.

C. They are replaced by volcanic eruptions.

D. They are produced constantly from nutrients.

53. In one of the steps of the carbon cycle, a person exhales a molecule of carbon dioxide (CO2) into the atmosphere. Which of the following is most likely to happen next to the atom of carbon in this molecule?

A. It may be used as part of a sugar in a plant.

B. It may become part of a protein in an animal.

C. It may be consumed as a fossil fuel is burned.

D. It may be decomposed into carbon and oxygen by a bacterium.

Answers

1. A

2. D

3. C

4. Sample student responses can be found here.

5. D

6. C

7. B

8. Sample student responses can be found here.

9. A

10. A

11. C

12. C

13. Sample student responses can be found here.

14. B

15. B

16. C

17. D

Quiz 2:

18. A

19. C

20.

21. C

22. A

23. C

24. C

25. C

26. B

27. B

28. A

29. B

30. D

31. B

32. D

33. Sample student responses can be found here.

34. D

35. B

36. A

37. D

38. B

39. D

40. B

41. B

42. D

43. C

44.

45. A

46. A

47. B

48. C

49. C

50. C

51. B

52. B

53. A

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