random 500
The relationship depicted in the figure between fire frequency and grass connectivity is:
a) Negative
b) Positive
c) Antagonistic
d) Adverse
b) Positive
Mesquite percent pod removal differed between the 20 and 60 days for?
a) the insects and rodents treatments
b) the cattle treatment
c) the birds treatment but not the rabbits treatment
d) the deer and hogs treatments
d) the deer and hogs treatments
In drier climates, which of the following soils would have the highest probability of supporting plant species characteristic of wetter climates?
a. Sandy soils
b. Silty clay soils
c. Clay soils
d. Clay loam soils
a. Sandy soils
A non-heritable shift in the physiological state of an organism in response to exposure to an environmental condition is:
a. Natural selection
b. Acclimation
c. Mutation
d. Genetic drift
b. Acclimation
Symbiosis is a process:
a. That is neutral for both organisms in the relationship
b. In which both organisms benefit from the relationship
c. In which both organisms are negatively impacted by the relationship
d. In which one organism is benefited and the other negatively impacted by the relationship
b. In which both organisms benefit from the relationship
Which of the vegetation states in the figure is the most stable:
a) Grassland
b) Grass-shrub transition
c) Shrubland
d) Not enough information provided to determine
d) Not enough information provided to determine
Mesquite percent pod removal:
a) was consistently greater for the cattle treatment that the other treatments for both sampling date
b) did not differ among the rabbits, deer and hogs treatments for either sampling date
c) differed between the rodents and rabbits treatments at the 20 days date but not at the 60 days date
d) differed between the insects treatment and the none (control) treatment for both sampling dates
b) did not differ among the rabbits, deer and hogs treatments for either sampling date
Which of the following is FALSE?
a. C4 plants are considered to be of tropical origin
b. C3 plants are light saturated at lower levels of light than are C4 plants
c. C3 plants use water more efficiently than do C4 plants
d. C4 plants use nitrogen more efficiently than do C3 plants
c. C3 plants use water more efficiently than do C4 plants
In contrasting C3 and C4 plants, which of the following statements is most correct?
a. C3 plants reduce carbon via the Calvin-Benson cycle, but C4 plants do not.
b. Photorespiration is generally only detectable in C3 plants
c. C3 plants tend to have higher temperature optima for photosynthesis than C4 plants.
d. C3 plants tend to have higher water use efficiencies compared to C4 plants
b. Photorespiration is generally only detectable in C3 plants
The main distinction between nutrient and energy dynamics in rangeland ecosystems is:
a. Nutrients flow through ecosystem components while energy is cycled
b. Nutrients cycle through ecosystem components while energy flows
c. Nutrients are confined to living portions of the ecosystem while energy is not
d. The main source of all nutrients is the soil while the sun supplies energy
b. Nutrients cycle through ecosystem components while energy flows
Which of the statements is most correct about fire from the figure?
a) Grassland can be maintained with low fire frequency
b) Shrubland can be maintained with high fire frequency
c) Fire is needed with sufficient grass connectivity to prevent the degredation of this site from grassland to shrubland
d) not enough information provided to determine
c) Fire is needed with sufficient grass connectivity to prevent the degredation of this site from grassland to shrubland
Plant communities in mesic and arid systems are primarily constrained by _____ and _____ resources, respectively:
a) aboveground, belowground
b) belowground, aboveground
c) soil water, light
d) light, soil water
a) aboveground, belowground
Increasing niche overlap leads to increasing:
a. Commensalism
b. Competition
c. Predation
d. Mutualism
b. Competition
Phototropism is:
a. A response to gravity
b. A response to moisture
c. A response to temperature
d. A response to light
d. A response to light
The Principle of Limiting Factors states:
a. That all soil nutrients are equally important
b. That nitrogen is always the first limiting nutrient
c. That the limiting nutrient affects only the dominant plant species
d. That plant processes are controlled by the resources present in the least amount in relation to that required by the plants
d. That plant processes are controlled by the resources present in the least amount in relation to that required by the plants
Which of the statements is most correct about heterogeneity from the figure?
a)Resource heterogeneity and potential degradation are not coupled
b) reducing resource heterogeneity is often associated with shifting the plant community to one dominated by woody plants
c) resource heterogeneity increases as grass connectivity decreases resulting in 'nutrient islands' or 'islands of fertility' associated with woody plants
d) Not enough information provided to determine
c) resource heterogeneity increases as grass connectivity decreases resulting in 'nutrient islands' or 'islands of fertility' associated with woody plants
Current year biomass:
a) is reduced by a similar magnitude by both fall and summer burns in a wet and dry spring relative to the control plots
b) is influenced by burning when a dry spring occurs, but not for a wet spring
c) is influenced more by summer burning than by fall burning in a wet spring
d) is influenced more by fall burning than by summer burning in a dry spring
c) is influenced more by summer burning than by fall burning in a wet spring
The higher water use efficiency of C4 plants is most closely correlated with which of the following physiological factors:
a. Optimum temperatures
b. CO2 compensation point
c. Photorespiration
d. Respiration rate
b. CO2 compensation point
Plant competition is characterized by:
a. Equal quantities of resources required by plants
b. Scarcity of necessary resources
c. Equal growth of competing species
d. Uniform distribution of all species in the community
b. Scarcity of necessary resources
Hardin’s “Tragedy of the Commons” theory held that:
a. All uses are completely competitive on wildlands
b. All individuals using a resource in common will tend to maximize their own benefits even if the resource is degraded
c. Common use is not possible under a democracy
d. Community held lands will always be higher in productivity than private lands
b. All individuals using a resource in common will tend to maximize their own benefits even if the resource is degraded
Dyksterhuis used plant response groups in his rangeland condition classification to generate condition estimates for catergories that included:
a) early-seral, mid-seral. and late-seral
b) Poor, fair, good and excellent
c) degraded, transitioning, restored, and healthy
d) native, introduced, invaded and exotic
b) Poor, fair, good and excellent
Purple threeawn current year biomass:
a) is reduced by a similar magnitude by both fall and summer burns in a wet and dry spring relative to the control plots
b) is influenced by burning when a dry spring occurs, but not for a wet spring
c) is influenced more by fall burning than by summer burning in a wet spring
d) is influenced more by summer burning than by fall burning in a dry spring
c) is influenced more by fall burning than by summer burning in a wet spring
The ecological law which states that all organisms survive between an ecological maximum and minimum in relation to environmental factors is referred to as the:
a. Law of the Minimum
b. Law of Limiting Factors
c. Law of Tolerance
d. Law of the Maximum
c. Law of Tolerance
The timing of life cycle or annual cycle events in relation to environmental cues is:
a. Physiology
b. Autecology
c. Phenology
d. Physiognomy
c. Phenology
Water moves through the soil-plant-atmosphere continuum in response to:
a. Temperature
b. Relative amounts of soil water
c. Carbohydrate reserves
d. Gradients of free energy
d. Gradients of free energy