Lack of water common in summer; seasonal temperature variations; maintains by periodic fires.
The LEAST effective means of controlling pest species such as rats or roaches over a long period of time is generally to
distribute pesticides throughout the habitat
Which of the following is characteristic of a fast-moving stream ecosystem?
high levels of dissolved oxygen
All of the following are true about Earth's ozone layer EXCEPT:
its thickness has remained consistent over time
Grass ® Cricket ® Prairie chicken ® Coyote ® Vulture
In which organism in the food chain above would the biological magnification of DDT concentration be most obvious?
A species of malaria-carrying mosquito lives in a forest in which two species of monkeys, A and B, coexist. Species A is immune to malaria but species B is not. The malaria-carrying mosquito is the chief food for a particular kind of bird in the forest. If all of these birds are eliminated suddenly by hunters, which of the following would be the immediate observable consequence?
Increased mortality in monkey species B
If, in country I, infant mortality declined and the birth rate remained the same, then initially the population would be expected to
be even more concentrated in the young age classes
All of the following statements about the pyramid of biomass are correct EXCEPT:
The base of the pyramid generally represents primary consumers.
The organic and inorganic materials in all the organisms in the diagram will eventually return to the environment by the action of
All of the following statements about the diagram are correct EXCEPT
only two trophic levels are depicted
Competitive exclusion is most likely to occur between two
closely related species occupying the same niche
a study of the metabolic rate in a terrestrial community shows that the energy released by respiration exceeds the energy captured in photosynthesis. Which of the following situations is occurring?
Community biomass is decreasing
Over 10 inches of precipitation per year; long, cold winters and short summers; dominant vegetation is evergreen trees.
Which of the following organisms is most likely to be located at the apex of the pyramid of biomass?
Gradual transition over time from one type of biological community to another.
If the larvae of a particular species of mosquito are to survive to the adult stage, the eggs must be laid in the trapped pool of water of the northern pitcher plant. The mosquito larvae provide no apparent benefit or harm to the pitcher plant. This type of interaction is an example of
During the carbon cycle, which of the following carbon compounds would be utilized as an energy source by heterotrophs?
In Country I, approximately what percentage of the individuals were younger than fifteen years of age?
Over the next 10-15 years, the stabilization of country I's population at its current size would require that
each couple produce fewer children than the number requred to replace themselves
In traveling from a forest ecosystem to a grassland, one notes that the trees gradually give way to prairie grasses. The critical factor governing this shift is usually the
availability of water
Which of the following is an important characteristic of the tropical rain forest biome?
Rapid recycling of nutrients
Species that utilize the same source of nutrition within a food web can best be described as
occupying the same trophic level
Less than 10 inches of precipitation per year; extremes of hot and cold throughout the year; large daily temperature variations