Ecology Homework Questions
What type of plant grows on other plants and is often rooted on the damp upper branches? A: Neophyte B: Saprophyte C: Epiphyte D: Mycorrhizae
C
Where would NPP be lowest? A: A freshwater lake B: An estuary C: A subtropical ocean gyre D: A stream
C
One reason to randomly sample is because: A: It helps to create consistent data B: It ensures significant p-values C: It helps to prevent bias D: It generates the most data
C
The formation of a savanna biome is largely due to the _______ cell. A: Hadley B: Ferrel C: Polar
A
The explanation(s) for the trend in greater species richness near the tropics than near the poles is: Select all that apply. A : Variation in energy input. B : Greater evolutionary age of the tropics. C : Decrease in habitat fragmentation. D : Increase in trade winds.
A,B
About _______% of flowering plants possess morphological features that serve to disperse seeds. A: 10 B: 20 C: 30 D: 70
A
Based on the survivorship curves, which depicts circumstances where risk of mortality is greatest at older ages? A: Type I B: Type II C: Type III D: Type I and II
A
If consumption efficiency of an organism was .25, assimilation efficiency .25 and production efficiency .45 what would the trophic transfer efficiency of this organism be? A: 2.8% B: 0.028% C: 280% D: 28%
A
It would be most difficult for a species to invade a community where the resource utilization of current resident species ________________. A : Does not overlap. B : Overlaps.
B
In the Lotka-Volterra Model, there are numerous factors that determine the populations of the two competing species. If we were to graph the zero isoclines of two competing species, such as the baboon and cheetah, then we can learn how each population's size will be affected under certain ecological circumstances. Using the notation for the model from the text, what would happen to the population of baboons (species 1) and cheetahs (species 2) if K2 > K1 α21 and K2 α12 > K1? A: Baboons would go extinct and cheetahs would reach their carrying capacity. B: Cheetahs would go extinct and baboons would reach their carrying capacity. C: Cheetahs and baboons would reach stable equilibrium populations and competitively coexist. D: Both answers a and b are possible, but it is not possible to determine which without more data.
A
Present day distribution patterns of plants and animals are primarily due to: A: Changes in climate, particularly during the ice ages of the Pleistocene. B: Reciprocal transplantation C: Co-evolving relationships D: Island speciation events
A
Species competing but coexisting by utilizing slightly different resources is thought of as ______ A: differential resource utilization. B: a realized niche. C: a fundamental niche. D: niche complementarity.
A
The term aPN in the Lotka-Volterra predator prey models denotes _______ A: The consumption rate of prey B: The overall impact of prey on predators C: The change in predator numbers D: The zero isocline for prey
A
You are flying over a mountain range and notice that the east facing slope of the range looks dry relative to the west facing slope. How could this be explained? A: The east facing slope is not hit by prevailing winds. As a result descending air on the east facing slope is very dry. B: The west facing slope is hit by prevailing winds. As a result the east facing slope gets a lot of rain. C: There is no explanation. D: The east facing slope is hit by prevailing winds. As a result all moisture is lost on the west facing slope.
A
You determine that two species of birds coexist in the same tree, but that they have different feeding behaviors that prevents them from competing with one another for resources. One bird species feeds on insects found in the bark of this tree, while the other bird species feeds on insects at the branch tips. One explanation of your observation could be that: A: coexistence is due to niche differentiation. B: coexistence is due to shared resource utilization. C: coexistence is not due to resource specialization. D: None of the choices are correct.
A
You observe ten species of trees in a rainforest. You learn that species with similar light requirements tend to differ in terms of preferred soil textures and vice versa. You should recognize this pattern as A: niche complementarity. B: intraspecific competition. C: interspecific competition. D: niche differentiation.
A
Ecological speciation is comprised of which components: Select all that apply. A : Differing environments or ecological interactions that select for local adaptation B : A means of reproductive isolation C : Hybridization D : All of the above
A,B
When the order of colonization impacts competitive outcomes: Select all that apply. A : It is called a priority effect. B : Species that may otherwise be superior competitors may lose competitive outcomes. C : It is called dominance-controlled. D : None of these choices are correct.
A,B
If genetic differentiation has occurred it could be due to: Select all that apply. A : Genetic drift B : Adaptive variation C : Gene flow D : Microsatellites
A,B,C
Most primary production does not pass through the live consumer system. Which of the following is correct relative to this statement? Select all that apply. A : Much primary production dies without being grazed and supports the decomposer system. B : Not all primary productivity is assimilated to biomass because a proportion is lost to respiratory heat. C : Plant biomass that is eaten by herbivores and herbivore biomass eaten by carnivores is not entirely incorporated into consumer biomass. What is not used is lost in feces and is used by the decomposer system. D : All primary productivity is grazed.
A,B,C
Conditions are physiochemical features of the environment, such as: Select all that apply. A : Temperature B : Humidity C : Prey density D : Salinity
A,B,D
Which of the following are examples of dispersal? Select all that apply. A : The passive transport of seeds on a duck to another site B : A honey badger leaving its mothers care C : A bird flying from California to Alaska for the winter D : A young male mountain lion seeking out its own territory
A,B,D
In some tropical mountains, ecologists have noticed bird species diversity declining in recent years despite seeing normally low elevation species beginning to appear in higher elevations. They blame climate change and increasing temperatures. What might be going on? Select all that apply. A : As temperatures increase, upper elevation conditions become increasingly favorable to lower elevation species. B : Increasing temperatures at high elevations are driving high elevation species lower to seek cooler temperatures. C : Lower elevation species are moving up the mountain and out competing the species traditionally found there. D : As temperatures decrease, upper elevation conditions become increasingly favorable to lower elevation species.
A,C
Which of the following are examples where primary succession could occur? Select all that apply. A : A volcano erupted and created new bedrock B : A tornado clears farm land C : A glacier retreats and exposes substrate D : Waves that sweep the shore
A,C
How has human activity since the 19th century affected atmospheric concentrations of methane? Select all that apply. A : Since 1800, the atmospheric concentration of methane has more than doubled B : Since 1800, the atmospheric concentration of methane has increased by less than 200% C : Has increased at a rate even faster than carbon dioxide D : The increase has been associated with biomass burning and the creation of landfills
A,C,D
Variation in your data affects the standard error. Your standard error will be smaller if: Select all that apply. A : The effect is more consistent or stronger B : The sample size is smaller C : The effect is weak D : The sample size is larger
A,D
When one studies metapopulations the following can occur: Select all that apply. A : Subpopulations can go extinct B : Subpopulations are usually more stable than the metapopulation C : Like islands the smallest patches are often the most frequently colonized D : Subpopulations can be very similar in size to one another
A,D
As climate has changed over evolutionary time scales, different organisms have responded by: A : Advancing their range B : Becoming fragmented into isolated patches C : Retreating their range D : Eventually rejoining after being fragmented
All of the above
Competition between individuals of the same species can have effects on their ________. Select all that apply. A : Survival B : Growth C : Reproduction D : Access to mates
All of the above
Ecologists may use which of these approaches to answer research questions? Select all that apply. A : Mathematical models B : Controlled laboratory experiments C : Manipulative field experiments D : Observational data
All of the above
Because of how sunlight hits the surface of Earth: Select all that apply. A : Heating by sunlight is greater at the North and South Poles B : Heating by sunlight is greater at the Equator C : Temperatures are cooler at the Equator D : Water redistributes heat to temperate and polar regions
B,D
In highly agricultural areas, fencerows provide habitat and refugia for wildlife. You might assume: Select all that apply. A : Metapopulation analysis is more appropriate now than before land modification to agriculture. B : Some species may go extinct in some fencerows but not others. C : Smallest fencerows may see the most frequent species extinctions D : For it to be a metapopulation organisms must be able to go from one fencerow to other fencerows.
All of the above
Niche differentiation can be the result of: (Select all that apply.) A : species evolving separately with distinct niches. They were never competitors, nor are they now. B : the species are competitors now. C : the species were competitors in the past, but do not compete now. D : competition in the past eliminated other species and now only those species with different niches exist.
All of the above
What is an example of a reason why an ecologist would employ a molecular marker? Select all that apply. A : To differentiate one individual of a species from another B : To measure the amount of gene flow between populations of a species C : To trace lineages of a species from generation to generation D : To detect adaptive variation between populations of a species
All of the above
Which of the following would be considered an island where species diversity would be limited by area? Select all that apply. A : A lake B : An island in the Pacific ocean C : A gap of forest cleared D : Soil that has much less phosphorous and nitrogen than the soil surrounding it
All of the above
A niche for a species of salamander is determined by the density of individuals in the area, soil temperature, amounts of precipitation, and food availability. Thus, the niche would be modeled as a: A: Fundamental niche dimension B: A four-dimensional niche volume C: A two-dimensional niche volume D: You could not model this niche
B
According to the Rockstrom paper, which of Earth's critical "life-support" systems has been perturbed most beyond Rockstrom's "safe" level? A: Climate change B: Biodiversity C: Phosphorous cycle D: Ocean acidification
B
Assume that resources for a community of species are available on a continuum. A common species of bird utilizes a particular portion of this continuum. What term defines the length of the portion of resources that this bird uses? A: Module B: Niche breadth C: H D: Pi
B
If R0 were calculated as 0.88 for a population of desert mice, what would this imply? A: That 12% of the population died. B: Each generation the population declined by 12%. C: Each generation is procuring an extra 88% of the population. D: That 88% of the population has been lost.
B
If a plant were grazed upon by individuals of a snail population, and the plant produced compounds to deter further feeding, then what might occur? A: The plant will do nothing different since it is now chemically defended. B: The plant may experiences a trade-off of some sort, because there is likely a cost to producing the compounds that deter grazers. C: The plant will not experience any trade-offs since it has evolved with this grazing snail. D: The snail will likely continue to graze because it is immune to the chemicals this plant produces.
B
If a species is a weak competitor relative to another species that is a superior competitor, the weak competitor may be able to persist if: A: it is a good colonizer and the environment homogenous. B: it is a good colonizer and the environment is heterogeneous. C: only the environment needs to be heterogeneous. D: the species needs only to be a good colonizer.
B
If birth and death rates are density dependent, then the density of a population will settle near ______________ A: No set point B: Carrying capacity C: When mortality is at its lowest D: When birth rates are at the highest
B
Is the combination of conditions and resources that allow that species to exist, grow, and reproduce in the presence of specified other species that might be harmful to its existence. A: A fundamental niche. B: A realized niche. C: Niche differentiation. D: Niche complementarity.
B
One reason why the melting of oceanic ice will potentially be problematic for the atmosphere and global warming is _____________. A: Because less greenhouse gases will be absorbed by ice B: Because the ice holds huge quantities of gaseous methane C: Because the ice holds huge deposits of carbon dioxide D: Because it provides habitat for all polar animals
B
Predation and competition Select all that apply. A : Are mutually exclusive ecological processes and do not simultaneously help us understand most population fluctuations B : Are often overlapping processes that are both needed to explain population changes C : Overlap more in plant interactions than in animal interactions D : None of the above
B
Several finches from the mainland of South America fly to a Pacific Island archipelago and colonize the first island they get to. Over time, individuals on this island fly to a nearby island and colonize it. This process occurs repeatedly and over evolutionary time each colonizing bird becomes its own species due to distinct ecological and environmental processes taking place on each island. What type of speciation best describes this example? A: Lamarckian speciation B: Allopatric speciation C: Sympatric speciation D: Ecological
B
Species are often excluded from habitats in which they could exist perfectly well in the absence of interspecific competition. As an example, Dolly Varden char can live in the white-spotted char zone, but only when A: that zone is highly populated with white-spotted char. B: there are no white-spotted char present. C: the two species are found together, the water temperature is higher than usual, and Dolly Varden char become more aggressive to individuals of its own species. D: None of the choices are correct.
B
The Lotka-Volterra predator-prey models demonstrate ______________? A: Why prey will typically go extinct in most situations B: Why predator numbers often lag behind prey numbers C: Why prey numbers often lag behind predator numbers D: That predator and prey populations are unrelated
B
The connection between food web complexity and stability is more complex than once thought. Currently we think that populations are actually _________ stable when the web is complex and the aggregate whole community might be _________ stable when the web is complex. A: More, less B: Less, more C: More, more D: Less, less
B
The use of fertilizer has produced mixed environmental outcomes. Why? A: Because it has promoted more crop growth but also an increase in plant diseases B: Because it has promoted more food and less starvation but has also led to aquatic dead zones and amphibian deformities C: Because it has led to less hunger and more biodiverse oceans D: Because it has produced less hunger and fewer human related cancers
B
Under variable conditions, competition may only rarely "run its course," and the outcome cannot be predicted simply by _________. A: application of environmental heterogeneity B: saying it's due to the Competitive Exclusion Principle C: interspecific competition
B
What does net primary productivity represent? A: The actual amount of new biomass available for heterotrophs to consume. B: The actual rate at which new biomass is produced for heterotrophs to consume. C: The actual number of new living organisms in a unit area for heterotrophs to consume. D: The actual productivity of an ecosystem and how much respiration occurs over time.
B
What term would be used to describe the process whereby nitrogen is converted into molecules that plants can use? A: Nitrogenation B: Nitrogen fixation C: Nitrogen recovery D: Nitrogen flux
B
When predators consume prey there is not always a negative effect on prey populations because? A: Prey hide more when predators are nearby B: Predation can reduce intraspecific competition C: Predators tend to select the healthiest prey D: Predators tend to select breeding individuals as their prey
B
Which of the following choices is a term that refers to diversity between communities? A: Alpha diversity B: Beta diversity C: Kappa diversity D: Gamma diversity
B
Which term describes the number of species found in a particular area? A: Niche B: Species richness C: Habitat density D: Organismal density
B
Who challenged the ideas of Hairston et al. and what did they contend? A: The hypothesis by Hairston et al. was never challenged because it has been empirically demonstrated that the world is green due to top-down control. B: Murdoch challenged the ideas of Hairston et al. and argued that the world is green because herbivores are limited by the defenses plants have evolved. C: Pimm in 1966 argued that the world is green because herbivores are overwhelmed by their predators. D: Hanski and Levins aregued that the world may still be green even if it is controlled from the bottom up.
B
Diversity indices take into account Select all that apply. A : Species competitive abilities. B : Species richness. C : Available energy. D : Evenness of species.
B,D
You have been studying a plant species for the last three years. On an island trip you notice that the same species there does not have a similar leaf morphology compared to that on the mainland. Specifically, the island plants do not have sharp points around the perimeter of each leaf and are instead very smooth. You also learn that this island is devoid of deer, which specialize on this plant. What might you hypothesize regarding the morphological differences between these plants? A: Leaves have evolved differently on the island because of climate. B: Leaves have no need on the island for morphological defenses because their primary predator is not found there. C: There is no way the two plants are the same species. D: Specialized predators on the island ate the spikes off of these leaves.
B
You have researched outbreaks of West Nile virus. You see a pattern whereby the numbers of incidences of outbreaks increases ten days after a period of precipitation in which daily temperature is below 20 degrees Celsius, soil moisture is between 50% to 65%, and relative humidity is above 60% over a continuous period of 5 days. What can you conclude from these data? A: You can conclude that these environmental factors are why West Nile virus outbreaks increase. B: You can conclude that these environmental factors are correlated with an increase in the number of West Nile virus outbreaks. C: You can conclude that these environmental variables are correlated with an increase in the number of west nile virus outbreaks and prove the causal relationship. D: You can conclude that west nile virus is not affected by abiotic variables.
B
You have studied a population of garter snakes to understand how recruitment changes over time. When the density of snakes was at an average of 5 per 50 square meters recruitment was low. When that density increased to 20 per 50 square meters recruitment was also low. However, when densities were near 12 garter snakes per 50 square meters recruitment was at its highest. This is an example of a ___________ curve. A: Calibration B: Dome-shaped net-recruitment C: Type I D: Sigmoidal
B
You learn that an organism is using abiotic environmental resources to assemble carbohydrates and proteins, and then forming them into tissues and organs. This organism is likely a: A: Heterotroph B: Autotroph C: Mammal D: All of the above
B
You might expect the evolution of specialized animal pollinators and specialized flowers because ______________. A: This ensures that both can survive. B: A specialist pollinator will likely be able to discriminate between plants and therefore not move pollen between heterospecifics. C: There is no precedent that suggests that this should be expected. D: A specialist pollinator will likely only visit one plant and pollinate only that one plant which will therefore increase the plants fitness.
B
You review successional data, which show a subset of plants colonizing a gap in the following order: Common chickweed (annual)-> salvias (herbaceous perennial shrub)-> toyon (woody perennial shrub). Using these data, does it appear that plants are following a typical sequence of dominant vegetation? If so, which species might follow? A: It does not appear that the typical sequence is being followed. B: Yes, these data show that the typical sequence is being followed. The next species will likely be a late succession plant. C: Yes, these data show that the typical sequence is being followed. The next species will likely be an early succession plant. D: Yes, these data show that the typical sequence is being followed. The next species will likely be an herbaceous perennial.
B
__________ are mutualisms formed between plant root tissue and fungi. A: Cruciferae B: Mycorrhiza C: Arbuscular ectobiota D: None of the above
B
Island endemics evolve because they: Select all that apply. A : Can exchange genetic material with mainland species B : Are isolated from individuals of the mainland species C : Do not have gene flow with mainland species D : They do not hybridize with other species
B,C
A niche can be thought of as being: Select all that apply. A : The same thing as a habitat B : A summary of what an organism can tolerate C : A summary of what an organism requires D : A modern concept, proposed by Hutchison in 1957 E : An n-dimensional hypervolume
B,C,D,E
A bird feeds on the fruit of a plant. The bird will later regurgitate the seed. However, in the process of digesting the fruit and regurgitating the seed, the embryo is made non-viable. This is ___________. A: An example of a mutualism because the bird disperses the plants seeds. B: An example of a coevolutionary relationship because both are specialized. C: Not an example of a mutualism because the bird destroys the seed and so it is never actually benefiting the plant. D: None of the above
C
A zebra was bred in captivity with a horse. The resulting offspring were all sterile. This can be thought of as a ________ A: Sympatric species B: Allopatric species C: Post-zygotic barrier D: None of the above
C
If dN/dt = rN, then any increase in the population will be _______ A: Linear B: Logistic C: Exponential D: S-shaped
C
If you were given a measure of the total fixation of energy via photosynthesis, you would have which? A: Primary productivity B: Rauto C: Gross primary productivity D: Secondary productivity
C
If you were standing in the tropics, which direction would the prevailing winds blow? A: From the north B: From the south C: From the east D: From the west
C
In deep lakes and ponds, no light reaches the lower layer of the water column. Which of the following would you predict might take place at this bottom layer? A: There will be an abundance of predators and prey B: There will be many aerobic bacteria C: Dissolved oxygen levels will be low D: Primary productivity will be high
C
Oak tree species are quite abundant in the southern California landscape. These species are long-lived, even though they experience drought. What would you predict their root structure to be like? A: They likely have shallow roots that spread out across wide areas B: They likely have one single, shallow root C: They likely have a very deep root structure that reaches through many layers of soil D: They likely have a root structure that branches out but can move deeper into layers of soil when drought conditions occur.
C
The greatest contribution to the total human input of nitrogen per year in is __________. A: Fossil fuels burning B: Nitrogen fixation associate with agricultural crops C: Manufacturing of synthetic fertilizer D: Deforestation
C
The rate of phosphorous flow through the global environment is three times faster now than before the industrial and agricultural revolutions. The main problem with this accelerated cycle is that? A: It results in acidification of the oceans B: It causes drastic alteration of ocean currents C: It causes eutrophication of freshwater lakes D: It initially slows the growth of freshwater vegetation
C
What do you call a series of similar communities that are in different stages of succession all in order? A: Successional timing. B: Sequential succession. C: Chronosequence. D: None of the above
C
Which community would you suspect receives high levels of radiation but does not convert much of that radiation to biomass? A: Tropical rain forest in Costa Rica B: Tropical rain forest in Ecuador C: Death Valley desert in California, United States of America D: A conifer forest in Alberta, Canada
C
Why do ocean waters become acidic as carbon dioxide is assimilated? A: Carbon dioxide produces more hydrogen ions in salt water B: Carbon dioxide is converted to calcium carbonate and that raises pH C: Carbon dioxide dissolved in water converts to carbonic acid D: Carbon dioxide does not play a role in ocean acidification
C
You take a research trip to Australia and observe that the wombat appears to be a similar looking species to a ground hog you have studied in North America. These two species have evolved in separate, but climatically similar environments, and they have developed closely corresponding adaptive features. This is a clear example of: A: Convergent evolution B: Environmental speciation C: Parallel evolution D: Allopatric speciation
C
_______ is when individuals of one species suffer a reduction in fecundity, survivorship, or growth as a result of exploitation or resources or interference by individuals of another species. A: Intraspecific competition B: Interference competition C: Interspecific competition D: Guild competition
C
Which abiotic processes are responsible for the Ferrel cells? Select all that apply. A : The Coriolis Effect B : Westerlies C : Hadley Cells D : Polar Cells
C,D
Experiments performed in the rocky intertidal zone by Robert Paine showed that the experimental removal of a predator had dramatic consequences to the structure of the community. What was the ultimate conclusion of this study? A: That predators can prey so heavily that they eventually reduce species richness to nearly zero. As a result species richness is reduced. B: That prey need spatial and temporal fluctuations to coexist, otherwise the community structure will collapse. When fluctuations do not occur, then species richness is significantly reduced. C: That predators have no impact on the structure of lower trophic levels. D: That predators can mediate coexistence by reducing the number of individuals of a species in the community that tend to dominate and as a result increase species richness more than if they were not present.
D
Regions of DNA that do not vary between individuals are referred to as what? A: Microsatellites B: Allele C: Locus D: Conserved
D
Species richness refers to: Select all that apply. A : How evenly distributed species are within a habitat. B : How productive species are within a community. C : The number of primary producers within a community. D : The total number of species within a community
D
Which of the following choices refers to the rate of production of biomass by heterotrophs? A: Biomass B: Net primary productivity C: Net ecosystem productivity D: Secondary productivity
D
Why would generalists survive better than specialists? A: There are not enough data to determine this. B: Generalists can more efficiently handle toxins with high specificity. C: Generalists did not survive more than specialists. D: Specialists have likely evolved adaptations to deal with a specific compound, whereas generalists must have adaptations for an array of compounds.
D
You are working on a research project to study insects in a tropical rainforest. You have collected some larvae from a species of interest and brought them back to lab. Within a few days of rearing them, you notice that many have been consumed from the inside out and are dead. Upon closer inspection you find that there is another species of insect larvae present. Speculate how this could have happened. A: The larvae cannibalized one another B: The larvae were attacked by a predatory insect C: It appears that you misidentified some of the larvae D: The larvae were apparently host of a parasitoid fly or wasp
D
