11.E: Ecosystem Ecology (Exercises)
- Page ID
- 123411
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11.1: The Scope of Ecology
Ecology is the study of the interactions of living organisms with their environment. One core goal of ecology is to understand the distribution and abundance of living things in the physical environment. Attainment of this goal requires the integration of scientific disciplines inside and outside of biology, such as biochemistry, physiology, evolution, biodiversity, molecular biology, geology, and climatology.
Review Questions
Which of the following is a biotic factor?
- wind
- disease-causing microbe
- temperature
- soil particle size
- Answer
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B
The study of nutrient cycling though the environment is an example of which of the following?
- organismal ecology
- population ecology
- community ecology
- ecosystem ecology
- Answer
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D
Free Response
Ecologists often collaborate with other researchers interested in ecological questions. Describe the levels of ecology that would be easier for collaboration because of the similarities of questions asked. What levels of ecology might be more difficult for collaboration?
- Answer
-
Ecologists working in organismal or population ecology might ask similar questions about how the biotic and abiotic conditions affect particular organisms and, thus, might find collaboration to be mutually beneficial. Levels of ecology such as community ecology or ecosystem ecology might pose greater challenges for collaboration because these areas are very broad and may include many different environmental components.
The population is an important unit in ecology as well as other biological sciences. How is a population defined, and what are the strengths and weaknesses of this definition? Are there some species that at certain times or places are not in populations?
- Answer
-
It is beneficial to consider a population to be all of the individuals living in the same area at the same time because it allows the ecologist to identify and study all of the abiotic and biotic factors that may affect the members of the population. However, this definition of a population could be considered a drawback if it prohibits the ecologist from studying a population’s individuals that may be transitory, but still influential. Some species with members that have a wide geographic range might not be considered to be a population, but could still have many of the qualities of a population.
11.2: Energy Flow through Ecosystems
Multiple Choice
Decomposers are associated with which class of food web?
A. grazing
B. detrital
C. inverted
D. aquatic
- Answer
-
B
The producer in an ocean grazing food web is usually a ________.
A. plant
B. animal
C. fungi
D. plankton
- Answer
-
D
Which term describes the process whereby toxic substances increase along trophic levels of an ecosystem?
A. biomassification
B. biomagnification
C. bioentropy
D. heterotrophy
- Answer
-
B
Free Response
Compare grazing and detrital food webs. Why would they both be present in the same ecosystem?
- Answer
-
Grazing food webs have a producer at their base, which is either a plant for terrestrial ecosystems or a phytoplankton for aquatic ecosystems. The producers pass their energy to the various trophic levels of consumers. At the base of detrital food webs are the decomposers, which pass their energy to a variety of other consumers. Detrital food webs are important for the health of many grazing food webs because they eliminate dead and decaying organic material, thus clearing space for new organisms and removing potential causes of disease.
11.3: Biogeochemical Cycles
Multiple Choice
The majority of the water found on Earth is:
A. ice
B. water vapor
C. fresh water
D. salt water
- Answer
-
D
The process whereby oxygen is depleted by the growth of microorganisms due to excess nutrients in aquatic systems is called ________.
A. dead zoning
B. eutrophication
C. retrophication
D. depletion
- Answer
-
B
Free Response
Why are drinking water supplies still a major concern for many countries?
- Answer
-
Most of the water on Earth is salt water, which humans cannot drink unless the salt is removed. Some fresh water is locked in glaciers and polar ice caps, or is present in the atmosphere. The earth’s water supplies are threatened by pollution and exhaustion. The effort to supply fresh drinking water to the planet’s ever-expanding human population is seen as a major challenge in this century.