ASHWORTH SC260 FULL COURSE

assignment 01

SC260 Ecology

Directions: Be sure to make an electronic copy of your answer before submitting it to Ashworth University for grading. Unless otherwise stated, answer in complete sentences, and be sure to use correct English spelling and grammar. Sources must be cited in APA format. Your response should be one (1) single-spaced page in length; refer to the "Assignment Format" page for specific format requirements.

1. Describe global patterns of atmospheric heating and circulation. What mechanisms produce high precipitation in the tropics? What mechanisms produce high precipitation at temperate latitudes? What mechanisms produce low precipitation in the tropics? (60 points)

2. Use what you know about atmospheric circulation and seasonal changes in the sun’s orientation to earth to explain the highly seasonal rainfall in the tropical dry forest and tropical savanna biomes. (Hint: Why does the rainy season in these biomes come during the warmer months?) (40 points)

______________________________________________________

This is the end of Assignment 01.

Assignment 08

SC260 Introduction to Ecology

General Directions: Be sure to make an electronic copy of your answer before submitting it to Ashworth University for grading. Unless otherwise stated, answer in complete sentences, and be sure to use correct English spelling and grammar. Sources must be cited in APA format. Your response should be one (1) single-spaced page in length; refer to the "Assignment Format" page for specific format requirements.

Instructions: Write an essay using the guidelines below. You will need to find at least three (3) outside sources for this essay, but you may need more to demonstrate a thorough examination of the topic. Do NOT copy and paste from the sources; summarize, paraphrase, quote, and document your sources correctly. Use APA style to document your sources.

Background: Throughout the world, there are numerous environmental problems resulting from human population pressure on local natural resources. A large proportion of ecological research is dedicated to finding solutions to these issues.

Objectives: Upon completing this assignment, you should be able to describe in-depth an ecological issue, including at least two different perspectives, and how this issue is representative of other similar issues.

Procedure: Pick an ecological crisis anywhere in the world that has attracted significant attention. Explain the history of the event including how the situation reached a crisis point. Document as many sides of the situation as possible and include the resolution, if any was reached, of the crisis. If there was no resolution, speculate on how the crisis may be resolved in the future.

Example topics include the following:

4 Northern spotted owl habitat vs. logging interests in Pacific Northwest

4 Battle over water rights for farmers or wild fish in Southern Oregon

4 Fresh water use for development or conservation of the Everglades in South Florida

Your essay will be evaluated on the following criteria:

1. Thesis Statement and Introductory Paragraph – Give an indication of the importance of this topic. (10 points)

2. Body Paragraphs – Discuss the topic in your own words using at least three (3) published sources of information, cited correctly in the paragraphs as needed. Discuss the history of the event including how the situation reached a crisis point. Document as many sides of the situation as possible. Be sure to organize the information in a logical manner and discuss the topic completely. (70 points)

3. Concluding Paragraph – Include the resolution, if any was reached, of the crisis. If there was no resolution, speculate on how the crisis may be resolved in the future. (10 points)

4. Grammar, Mechanics, and Bibliography – Be sure to edit and proofread carefully. Also include an APA-formatted bibliography listing your sources. (10 points)

This is the end of Assignment 08.

Question 1 of 20 5.0 Points

Most insects use external sources of heat to achieve their operative temperature range. Heinrich's research on the sphinx moth (Manduca sexta) indicates that some insects can thermoregulate by using their flight muscles and:

A. using their blood as a coolant.

B. decreasing their metabolic rate.

C. possessing an internal respiratory system.

D. using a countercurrent heat exchange mechanism.

Question 2 of 20 5.0 Points

The thermal stability of aquatic environments is a result of the:

A. high specific heat of water.

B. low latent heat of vaporization of water.

C. low latent heat of fusion of water.

D. All of the choices are correct.

Question 3 of 20 5.0 Points

Animals that rely mainly on external sources of energy for regulating body temperature are called:

A. epitherms.

B. endotherms.

C. ectotherms.

D. peritherms.

Question 4 of 20 5.0 Points

In general, reptiles are considered to be a/an:

A. poikilotherm.

B. homeotherm.

C. endotherm.

D. heterotherm.

Question 5 of 20 5.0 Points

Mammalian and avian aquatic endotherms use all of the following mechanisms to thermoregulate EXCEPT:

A. fat.

B. internal respiratory systems.

C. fur or feathers.

D. concurrent heat exchange.

Question 6 of 20 5.0 Points

The water availability for organisms is determined by:

A. internal dissolved ion concentrations.

B. external dissolved ion concentrations.

C. movement of water down its concentration gradient.

D. movement of water up its concentration gradient.

Question 7 of 20 5.0 Points

Aquatic organisms whose ionic concentration of their body fluids exceed that of their surroundings are:

A. hyperosmotic.

B. hypoosmotic.

C. isoosmotic.

D. osmotic.

Question 8 of 20 5.0 Points

In order to survive in the desert, a camel will employ which of the following mechanisms?

A. Face away from sun

B. Store water in its hump

C. Shed its fur

D. Allow its body temperature to rise

Question 9 of 20 5.0 Points

Saturation water vapor pressure:

A. increases with temperature.

B. decreases with temperature.

C. parallels vapor pressure density.

D. both increases with temperature and parallels vapor pressure density.

Question 10 of 20 5.0 Points

A cicada will use which of the following mechanisms in order to survive hot, dry conditions of the desert?

A. Nocturnal behavior

B. Burrowing

C. Torpor

D. Sweating

Question 11 of 20 5.0 Points

Herbivores, carnivores, and detritivores are all:

A. omnivores.

B. autotrophs.

C. heterotrophs.

D. animals.

Question 12 of 20 5.0 Points

Which kingdom has the higher carbon to nitrogen ratios?

A. Plantae

B. Animalia

C. Monera

D. Fungi

Question 13 of 20 5.0 Points

The main force in the development and refinement of prey defenses is/are:

A. nutrition.

B. predators.

C. the prey themselves.

D. mate choices.

Question 14 of 20 5.0 Points

Several studies indicate that environmental conditions dictate plant biomass allocation; plants grown in infertile soils will allocate more energy into __________ biomass.

A. leaf

B. stem

C. root

D. flower

Question 15 of 20 5.0 Points

Organisms which synthesize organic compounds using CO2 as a carbon source and inorganic chemicals as an energy source are:

A. chemosynthetic heterotrophs.

B. chemosynthetic autotrophs.

C. photosynthetic autotrophs.

D. photosynthetic heterotrophs.

Question 16 of 20 5.0 Points

Fitness is defined as the:

A. health of an individual organism.

B. ability of an organism to adapt to new environmental situations.

C. quality of offspring produced.

D. number of genes contributed by an individual to the next generation.

Question 17 of 20 5.0 Points

Secondary sexual characteristics are often considered a handicap because of increased:

A. predation.

B. competition.

C. parasitism.

D. infertility.

Question 18 of 20 5.0 Points

An instance of __________ selection occurs when the plumage of male birds becomes increasingly brighter over time.

A. contrasexual

B. intrasexual

C. intersexual

D. multisexual

Question 19 of 20 5.0 Points

Sociality is generally NOT accompanied by:

A. cooperative feeding.

B. defense of the social group.

C. unlimited reproductive opportunities.

D. restricted reproductive opportunities.

Question 20 of 20 5.0 Points

When investigating haplodiploidy, all of the following statements were found to be true EXCEPT:

A. siblings are more genetically related than an individual's own offspring.

B. males have one set of chromosomes.

C. kin selection is not implicated.

D. males develop from unfertilized eggs.

Question 1 of 20 5.0 Points

Locally adapted and genetically distinctive populations within a species are referred to as:

A. heterotypes.

B. metatypes.

C. genotypes.

D. ecotypes.

Question 2 of 20 5.0 Points

Within a population, if the average is selected for and the two opposing extremes are selected against, this is an example of __________ selection.

A. directional

B. disruptive

C. stabilizing

D. natural

Question 3 of 20 5.0 Points

Over time, average phenotypes become less common and the population becomes phenotypically more diverse as a result of __________ selection.

A. bimodal

B. directional

C. disruptive

D. stabilizing

Question 4 of 20 5.0 Points

Molecular biology has helped scientists examine the genetics and evolution of different species. Which of the following sequences is correctly ordered?

A. Restriction fragments, restriction enzymes, PCR, electrophoresis

B. PCR, restriction enzymes, restriction fragments, electrophoresis

C. Restriction enzymes, PCR, electrophoresis, restriction fragments

D. PCR, electrophoresis, restriction enzymes, restriction fragments

Question 5 of 20 5.0 Points

All of the following conditions are included in the Hardy-Weinberg equilibrium principle EXCEPT:

A. no mutation.

B. non-random mating.

C. large population size.

D. no immigration.

Question 6 of 20 5.0 Points

__________ is/are defined as a group of potentially breeding organisms within a species in a given space and time.

A. Density

B. Abundance

C. Distribution

D. Populations

Question 7 of 20 5.0 Points

Whittaker's research on North American tree distribution examined __________ gradients and concluded that the tree distribution was __________.

A. temperature; random

B. temperature; clumped

C. moisture; clumped

D. moisture; random

Question 8 of 20 5.0 Points

In order to determine whether a species is common or rare, ecologists use all of the following criteria EXCEPT:

A. habitat tolerance.

B. evolutionary existence.

C. geographical range.

D. local population size.

Question 9 of 20 5.0 Points

The rarest animal is the __________ and the rarest plant is the __________.

A. Northern spotted owl; Pacific Yew

B. Siberian tiger; Asplenium septrionale

C. Tasmanian devil; Welwitschia

D. Mountain gorilla; Prichardia Monroe

Question 10 of 20 5.0 Points

Rarity I can be described by the following indicators:

A. restricted range, narrow habitat tolerances, and small local populations.

B. restricted range, broad habitat tolerances, and large local populations.

C. extensive range, narrow habitat tolerances, and large local populations.

D. extensive range, broad habitat tolerances, and small local populations.

Question 11 of 20 5.0 Points

Which of the following word pairs are mismatched?

A. Random distribution: aggressive interaction

B. Clumped distribution: attraction to a common source

C. Regular distribution: antagonistic behaviors

D. Large scale distribution: substantial environmental changes

Question 12 of 20 5.0 Points

Which of the following is mismatched?

A. Eastern grey kangaroo: temperate and tropical forest

B. Western grey kangaroo: little seasonal variation in precipitation

C. Red kangaroo: savanna and desert

D. Western kangaroo: temperate woodland and shrubland

Question 13 of 20 5.0 Points

The Type I survivorship curve indicates:

A. low juvenile mortality and high mortality in older adults.

B. high juvenile mortality and low mortality in older adults.

C. low juvenile mortality and low mortality in older adults.

D. high juvenile mortality and high mortality in older adults.

Question 14 of 20 5.0 Points

Humans would best be represented by which of the following survivorships curves?

A. I

B. II

C. III

D. IV

Question 15 of 20 5.0 Points

The age distribution of a population can reveal:

A. growth potential.

B. survivorship.

C. reproduction.

D. growth potential, survivorship, and reproduction.

Question 16 of 20 5.0 Points

A group of subpopulations living in spatially isolated patches connected by exchange of individuals among patches is called a(n):

A. micropopulation.

B. megapopulation.

C. isopopulation.

D. metapopulation.

Question 17 of 20 5.0 Points

Which of the following indicates a population in decline?

A. R0=6.01

B. R0=0.601

C. R0=0

D. R0= - 0.601

Question 18 of 20 5.0 Points

Out of 1 million eggs laid by a mackerel, more than 999,990 die during the first 70 days of life either as eggs, larvae, or juveniles. The mackerel has a __________ survivorship curve.

A. Type I

B. Type II

C. Type III

D. Type IV

Question 19 of 20 5.0 Points

Which of the following equations bests represents the per capita rate of increase?

A. r = T/(ln R0)

B. r = (ln R0)/T

C. l = Nt/( Nt+1)

D. l = (Nt+1)/Nt

Question 20 of 20 5.0 Points

Type II survivorship curve indicates:

A. low juvenile mortality and high mortality in older adults.

B. high juvenile mortality and low mortality in older adults.

C. low juvenile mortality and low mortality in older adults.

D. equal chance of dying at any age.

Question 1 of 20 5.0 Points

Nt = N0 lt represents:

A. annual growth rate.

B. geometric population growth.

C. exponential growth rate.

D. logistic growth.

Question 2 of 20 5.0 Points

An annual plant when initially colonizing an area will probably demonstrate:

A. annual growth rate.

B. geometric population growth.

C. exponential growth rate.

D. logistic growth.

Question 3 of 20 5.0 Points

The exponential population growth equation can be used for:

A. populations with overlapping generations.

B. populations experiencing continuous growth.

C. populations with nonpulsed reproduction.

D. all of the populations listed above.

Question 4 of 20 5.0 Points

Density dependent factors include all of the following EXCEPT:

A. competition.

B. disease.

C. predation.

D. temperature.

Question 5 of 20 5.0 Points

Human populations are clumped on a large scale with the greatest concentration in:

A. Africa.

B. Asia.

C. Europe.

D. North America.

Question 6 of 20 5.0 Points

If the age distribution diagram is bottom heavy or pyramidal in shape, this indicates that the population is:

A. stable.

B. declining.

C. growing slowly.

D. growing rapidly.

Question 7 of 20 5.0 Points

If the age distribution diagram is bell shaped or the number of individual in each age class is evenly distributed, this indicates that the population is:

A. stable.

B. declining.

C. growing slowly.

D. growing rapidly.

Question 8 of 20 5.0 Points

If the age distribution diagram has the smallest concentration of individuals in the bottom portion or is considered to be an urn shape, this indicates that:

A. the population is stable.

B. the population is declining.

C. the population is growing slowly.

D. the population is growing rapidly.

Question 9 of 20 5.0 Points

A polymorphic locus is one that:

A. codes for more than one protein.

B. codes for both protein and lipid.

C. occurs in a population as more than one allele.

D. occurs on more than one chromosome.

Question 10 of 20 5.0 Points

The number of eggs laid by a female is called her:

A. fertility.

B. gonadosomatic index.

C. growth form.

D. fecundity.

Question 11 of 20 5.0 Points

A "forb" is a(n):

A. fish species living in the open ocean.

B. bird species having offspring independent at a young age.

C. plant species with woody tissue.

D. herbaceous, but non-graminoid, plant species.

Question 12 of 20 5.0 Points

The "K" in "K-selection" comes from the:

A. ecologist who coined it, Astrid Kodric-Brown.

B. shape of the age-vs.-mortality-rate plot for K-selected species.

C. "K" in the logistic growth equation.

D. Greek letter "kappa," symbolizing fecundity.

Question 13 of 20 5.0 Points

Which of the following is NOT a characteristic favored by K-selection?

A. Low intrinsic rate of increase

B. Late reproduction

C. Many, small offspring

D. Repeated bouts of reproduction

Question 14 of 20 5.0 Points

Which of the following environments for germinating seed is most likely to favor a plant species that makes many small seeds, compared to one that makes fewer larger seeds?

A. Nutrient limitation

B. Competition from established plants

C. Shade

D. Disturbance

Question 15 of 20 5.0 Points

"Riparian" refers to plant communities occurring:

A. in the tropics.

B. at high altitudes.

C. along the edges of deserts.

D. in transitions between riverbanks and upland areas.

Question 16 of 20 5.0 Points

The study of the relationship between climate and the timing of ecological events is called:

A. ecology.

B. phenology.

C. oenology.

D. climatology.

Question 17 of 20 5.0 Points

__________ show more variation in life history traits than any other group.

A. Insects

B. Mammals

C. Birds

D. Fish

Question 18 of 20 5.0 Points

Turner and Trexler found a __________ relationship between egg size and __________ in the darter populations that live in rivers and streams of central North America.

A. positive; gene flow

B. positive; egg number

C. positive; female size

D. negative; gene flow

Question 19 of 20 5.0 Points

Westoby, Leishman, and Lord found that on average, __________ produce the largest seeds.

A. forbs

B. woody plants

C. climbing plants and vines

D. graminoids

Question 20 of 20 5.0 Points

Which of the following are characteristics favored by K selection?

A. Rapid development

B. Small body size

C. Iteroparity

D. High rmax

Question 1 of 20 5.0 Points

Gause's "competitive exclusion principle" states that:

A. when two species occur together, competition is always prevented by some behavioral adjustment.

B. no two species can coexist indefinitely.

C. no two competing species can coexist indefinitely.

D. no two species with identical niches can coexist indefinitely.

Question 2 of 20 5.0 Points

In the Lotka-Volterra competition equations, if a21 > 1, then:

A. the population growth rate of species 2 is reduced more by each individual of species 1 than by each individual of species 2.

B. the population growth rate of species 2 is reduced more by each individual of species 2 than by each individual of species 1.

C. the population growth rate of species 2 is reduced equally by individuals of either species 1 or species 2.

D. we would also have to know the value of K2 to decide which of the above is true.

Question 3 of 20 5.0 Points

Analysis of the Lotka-Volterra competition model implies that two competitors can coexist only when:

A. interspecific competition is stronger than intraspecific competition.

B. intraspecific competition is stronger than interspecific competition.

C. intraspecific and interspecific competition are equally strong.

D. predation or parasitism is stronger than interspecific competition.

Question 4 of 20 5.0 Points

Two species occurring together in the same place are said to be:

A. competitors.

B. precocial.

C. mutualists.

D. sympatric.

Question 5 of 20 5.0 Points

The __________ niche defines the physical conditions under which a species might live, in the absence of interaction with other species.

A. functional

B. realized

C. principle

D. fundamental

Question 6 of 20 5.0 Points

The process of evolution toward niche divergence in the face of competition is called:

A. niche displacement.

B. niche evolution.

C. character displacement.

D. character evolution.

Question 7 of 20 5.0 Points

A species feeding on the tissue of its host, while not killing it directly, is a:

A. predator.

B. parasite.

C. parasitoid.

D. cannibal.

Question 8 of 20 5.0 Points

A "negatively phototaxic" amphipod will swim:

A. away from parasitic worms.

B. towards parasitic worms.

C. away from competing amphipods.

D. away from light.

Question 9 of 20 5.0 Points

The presence of parasitic protozoa in a culture of competing Tribolium castaneum and T. confusum:

A. increases the likelihood of coexistence.

B. decreases the likelihood of coexistence.

C. has no effect on the outcome of competition.

D. can reverse the outcome of competition.

Question 10 of 20 5.0 Points

The infestation of prickly pear cactus (Opuntia) in Australia was controlled by the release of a moth, Cactoblastis, which impacts cactus populations because it:

A. consumes cactus seeds.

B. consumes cactus pads.

C. introduces, as it attacks, fungi and bacteria that attack cactus pads.

D. both consumes cactus pads and introduces, as it attacks, fungi and bacteria that attack cactus pads.

Question 11 of 20 5.0 Points

The standard error of the mean is equal to:

A. the sample variance divided by the sample size.

B. the sample variance divided by the square root of the sample size.

C. the sample standard deviation divided by the square root of the sample size.

D. twice the square root of the sample size.

Question 12 of 20 5.0 Points

Gause's experiments with Paramecium and Didinium showed:

A. extinction of the predator, followed by extinction of the prey, in all habitats.

B. coexistence of predator and prey with oscillating population sizes, but only in the presence of refuges and predator reservoirs.

C. coexistence of predator and prey, but with oscillating population sizes, in all habitats.

D. coexistence of predator and prey at fairly constant population sizes, but only in the presence of refuges and predator reservoirs.

Question 13 of 20 5.0 Points

Periodical cicadas spend 13 or 17 years:

A. feeding in tree twigs before emerging as adults.

B. feeding on tree roots before emerging as adults.

C. as adults before laying eggs.

D. in a resistant, resting egg before hatching as larvae.

Question 14 of 20 5.0 Points

Schistosoma flukes attack their human hosts when those humans:

A. consume infected freshwater snails.

B. consume infected fish.

C. consume plant tissue bearing spores.

D. bathe in water containing infective cercariae.

Question 15 of 20 5.0 Points

Use of Procambarus crayfish to combat schistosomiasis in Africa:

A. is likely to be effective, and poses no important ecological risks.

B. is likely to be effective, but poses ecological risks because Procambarus is not native to Africa.

C. is unlikely to be effective, because the crayfish seem to eat infected snails only in the laboratory.

D. is unlikely to be effective, because the crayfish are just as suitable as hosts for the parasite as were the snails.

Question 16 of 20 5.0 Points

An interaction between individuals of different species that benefit both partners is called:

A. commensalism.

B. predation.

C. exploitation.

D. mutualism.

Question 17 of 20 5.0 Points

__________ mutualism describes a relationship where species are so dependent on their mutualistic relationship they cannot live in its absence.

A. Obligate

B. Critical

C. Facultative

D. Dispensable

Question 18 of 20 5.0 Points

Mycorrhizal fungi (directly) help their plant partners acquire:

A. sugars.

B. sunlight.

C. seed dispersal.

D. soil nutrients.

Question 19 of 20 5.0 Points

Ant-acacia trees provide several services to their mutualistic ant partners. These include:

A. enlarged thorns to host ant colonies.

B. nectar from foliar nectaries.

C. nectar from floral nectaries.

D. both enlarged thorns to host ant colonies and nectar from foliar nectaries.

Question 20 of 20 5.0 Points

The major benefit obtained by aspen sunflower, Helianthella quinquenervis, from its ant mutualists is:

A. improved attraction of pollinators.

B. reduced loss of leaf tissue to herbivorous insects.

C. more efficient extraction of soil nutrients.

D. reduced losses of seeds to seed predators.

Question 1 of 20 5.0 Points

Joseph Connell's "intermediate disturbance hypothesis" proposes that:

A. species diversity is highest at intermediate frequencies of disturbance.

B. species diversity is lowest at intermediate frequencies of disturbance.

C. population growth rates are highest at intermediate frequencies of disturbance.

D. competitive exclusion is fastest at intermediate levels of disturbance.

Question 2 of 20 5.0 Points

A "community" is defined as:

A. a group of organisms that all make their living in a similar way.

B. a group of individuals of a single species inhabiting a defined area.

C. the portion of a defined area that supports life.

D. an association of interacting species inhabiting a defined area.

Question 3 of 20 5.0 Points

In most ecological communities:

A. most species are extremely rare.

B. few species are very abundant.

C. most species are moderately abundant.

D. both few species are very abundant, and most species are moderately abundant.

Question 4 of 20 5.0 Points

Robert MacArthur's study of forest warblers suggested that:

A. fewer warbler species can survive in more complex habitats.

B. warbler species diversity increases with habitat complexity.

C. warbler species diversity decreases with habitat complexity.

D. most warblers have rather similar foraging niches.

Question 5 of 20 5.0 Points

Niches of single-celled algae, such as diatoms, seem most often to be distinguished by their requirements for:

A. different combinations of inorganic nutrients.

B. different light environments.

C. different water-flow environments.

D. different water temperatures.

Question 6 of 20 5.0 Points

In the Amazon forest, slight changes in soil properties tend to be correlated with:

A. similar, slight differences in plant communities.

B. no detectable differences in plant communities.

C. dramatic differences in plant communities.

D. dramatic differences in plant communities only if the soil property in question is moisture.

Question 7 of 20 5.0 Points

In Robert Paine's studies of the Washington intertidal community, which organism proved to be a keystone species?

A. The whelk Thais

B. Acorn barnacles

C. Chitons

D. The starfish Pisaster

Question 8 of 20 5.0 Points

In the Washington intertidal community studied by Robert Paine, the most important limiting resource is:

A. space.

B. light.

C. plankton.

D. nitrogen.

Question 9 of 20 5.0 Points

We can infer a statistically significant difference between two population means when:

A. our estimates of the two means are different.

B. the variances of the two means do not overlap.

C. the standard deviations of the two means do not overlap.

D. the 95% confidence intervals for the two means do not overlap.

Question 10 of 20 5.0 Points

Weaver ants provide effective protection of citrus trees because they:

A. remove harmful soft-scale insects (mealybugs).

B. remove all plant-feeding insects.

C. cultivate soft-scale insects, but do not allow them to feed on the trees.

D. cultivate soft-scale insects, but still allow them to be attacked by parasitoids and predators.

Question 11 of 20 5.0 Points

The Nile perch population explosion has been accompanied by:

A. a decrease in the dissolved oxygen in the shallowest portions of Lake Victoria.

B. a decrease in the dissolved oxygen in the deepest portions of Lake Victoria.

C. an increase in the dissolved oxygen in the deepest portions of Lake Victoria.

D. an increase in the dissolved oxygen in the shallowest portions of Lake Victoria.

Question 12 of 20 5.0 Points

Based on studies by Jane Lubchenko, what influence does the population density of the herbivorous intertidal snail, Littorina littorea, have on the number of algal species?

A. As snail density increases from low to medium, the number of algal species increases.

B. As snail density increases from medium to high, the number of algal species increases.

C. As snail density increases from medium to high, the number of algal species decreases.

D. Both as snail density increases from low to medium the number of algal species increases and as snail density increases from medium to high, the number of algal species decreases.

Question 13 of 20 5.0 Points

Teja Tscharntke simplified the food web associated with the wetland reed Phragmites australis by dividing the species into the following major trophic levels?

A. Plant, herbivore, piscivore, and granivore

B. Herbivore, carnivore, detritivore, and consumer

C. Herbivore, parasite, carnivore, and detritivore

D. Plant, herbivore, parasite, and carnivore

Question 14 of 20 5.0 Points

Net primary productivity is the primary productivity of an ecosystem, after subtracting energy lost in:

A. dead plant tissues.

B. inedible plant tissues.

C. respiration by primary producers.

D. respiration by primary consumers.

Question 15 of 20 5.0 Points

"Actual evapotranspiration" for an ecosystem refers to the amount of water that:

A. is taken up from soils by plant roots.

B. evaporates from soils.

C. is transpired by plants.

D. evaporates from soils plus the amount transpired by plants.

Question 16 of 20 5.0 Points

Leibig's "Law of the Minimum" stated that:

A. the lowest primary productivity occurs in the coldest ecosystems.

B. primary productivity is typically controlled entirely by climate.

C. primary productivity is typically controlled by both climate and soil nutrients.

D. a single soil nutrient typically limits primary productivity.

Question 17 of 20 5.0 Points

Experimental fertilizations in the Baltic Sea suggest that primary productivity there is normally limited by:

A. phosphorus.

B. nitrogen.

C. iron.

D. potassium.

Question 18 of 20 5.0 Points

The "trophic cascade hypothesis" emphasizes the role of:

A. nutrients in controlling primary productivity.

B. nutrients in controlling primary consumption.

C. grazing by herbivores in controlling primary productivity.

D. grazing by herbivores in controlling ecosystem nutrient levels.

Question 19 of 20 5.0 Points

In Hubbard Brook Experimental Forest, the largest "standing stock" of energy is represented by biomass of:

A. living plant tissues.

B. dead plant tissues.

C. invertebrate herbivores.

D. vertebrate herbivores.

Question 20 of 20 5.0 Points

An increase about 1,000 years ago in 13C content of human collagen from archeological sites in eastern North America probably records:

A. replacement of vegetables and grains in the diet by meat.

B. replacement of corn by beans and squash in the diet.

C. increasing consumption of corn.

D. increasing levels of 13C in soils.

Question 1 of 20 5.0 Points

The largest reservoir of phosphorus in most ecosystems is phosphorus:

A. in the atmosphere.

B. dissolved in water.

C. in rocks and sediments.

D. bound in animal tissues.

Question 2 of 20 5.0 Points

"Nitrogen fixation" refers to the conversion of:

A. carbon compounds to nitrogen compounds.

B. nitrogen gas (N2) to ammonia (NH2).

C. ammonia (NH3) to nitrogen gas (N2).

D. ammonium (NH4+) to nitrate (NO3-).

Question 3 of 20 5.0 Points

"Nitrification" is the conversion of:

A. carbon compounds to nitrogen compounds.

B. nitrogen gas (N2) to ammonia (NH2).

C. ammonia (NH3) to nitrogen gas (N2).

D. ammonium (NH4+) to nitrate (NO3-).

Question 4 of 20 5.0 Points

A major perturbation of the carbon cycle by human activity is associated with:

A. release of carbon from carbonate rocks.

B. release of carbon from fossil fuel deposits.

C. removal of carbon from the atmosphere in the industrial production of fertilizers.

D. accelerated removal of carbon from the atmosphere by forests.

Question 5 of 20 5.0 Points

In aquatic ecosystems, leaves with high lignin content decompose:

A. rapidly because lignin is a nutrient-rich compound.

B. rapidly because lignin enhances colonization by decomposing fungi.

C. slowly because lignin reduces colonization by decomposing fungi.

D. slowly because lignin is a carbon-poor compound.

Question 6 of 20 5.0 Points

In aquatic ecosystems, the major agents of decomposition are:

A. aquatic fungi.

B. bacteria.

C. algae.

D. detritivorous fish.

Question 7 of 20 5.0 Points

Clearcutting at Hubbard Brook Experimental Forest sharply:

A. increased export of nitrate (NO3-) in stream water.

B. decreased export of nitrate (NO3-) in stream water.

C. increased rates of denitrification in soils.

D. decreased deposition of ammonia (NH3) from the atmosphere.

Question 8 of 20 5.0 Points

In Judy Meyer and Gene Likens' study of phosphorus in Bear Brook:

A. most phosphorus inputs occurred during spring snowmelt.

B. phosphorus inputs were nearly constant over the year.

C. most phosphorus losses occurred during autumn leaf fall.

D. most phosphorus losses occurred during storms and snowmelt.

Question 9 of 20 5.0 Points

Fungi and bacteria release nitrogen stored in dead tissue through a decomposition process called:

A. nitrogen fixation.

B. ammonification.

C. denitrification.

D. nitrification.

Question 10 of 20 5.0 Points

Nitrate is converted to molecular nitrogen, N2, in a process called:

A. nitrogen fixation.

B. ammonification.

C. denitrification.

D. nitrification.

Question 11 of 20 5.0 Points

In stream ecosystems, nutrient retentiveness is:

A. not related to spiraling length.

B. positively related to spiraling length.

C. inversely related to spiraling length.

D. a logarithmic function of spiraling length.

Question 12 of 20 5.0 Points

"Primary" succession is succession that:

A. involves establishment of primary producers where there were none.

B. leads to establishment of a climax community dominated by primary producers.

C. occurs on newly exposed geologic substrates, not organic soil.

D. occurs where organic soils have been exposed but not destroyed by disturbance.

Question 13 of 20 5.0 Points

The pioneer species at Glacier Bay, Alaska include:

A. mosses.

B. Dryas.

C. alders.

D. horsetails.

Question 14 of 20 5.0 Points

During primary succession at Glacier Bay, overall plant species diversity:

A. first increases rapidly, then levels off.

B. increases steadily throughout succession.

C. increases slowly at first, then more rapidly after a few hundred years.

D. peaks at intermediate successional stages.

Question 15 of 20 5.0 Points

How does canopy shading influence succession of pines and deciduous trees in the Piedmont of North Carolina?

A. Canopy shading by deciduous trees is required for growth of pines.

B. Canopy shading by deciduous trees prevents establishment of pines until late in succession.

C. Canopy shading by deciduous trees prevents persistence of pines in late successional stages.

D. Canopy shading by pines prevents establishment of deciduous trees.

Question 16 of 20 5.0 Points

During succession in Arizona streams, nitrogen retention:

A. increases at first, but then declines late in succession.

B. increases steadily through succession.

C. increases slowly at first, but then rapidly late in succession.

D. increases rapidly at first, then plateaus late in succession.

Question 17 of 20 5.0 Points

According to the "facilitation" hypothesis, pioneer species modify the environment in ways that:

A. make it more suitable for their own survival, and less suitable for other species.

B. make it less suitable for their own survival, but more suitable for survival of other pioneer species.

C. make it less suitable for their own survival, but more suitable for survival of late-successional species.

D. make it less suitable for survival of all species.

Question 18 of 20 5.0 Points

According to the "inhibition" hypothesis, pioneer species modify the environment in ways that:

A. make it less suitable for other species.

B. make it less suitable for their own survival, but more suitable for survival of other pioneer species.

C. make it less suitable for their own survival, but more suitable for survival of late-successional species.

D. make it more suitable for survival of all species.

Question 19 of 20 5.0 Points

The change in plant, animal, and microbial communities in an area following disturbance or the creation of new substrate is called:

A. progression.

B. succession.

C. replacement.

D. colonization

Question 20 of 20 5.0 Points

According to the tolerance model of succession:

A. early successional species modify the environment making it less suitable for the establishment by all species.

B. early successional species modify the environment making it less suitable for early successional species, but neither less nor more favorable for late successional species.

C. early successional species modify the environment making it less suitable for early successional species, but more suitable for late successional species.

D. only early successional species can establish as succession begins.