the sum of all the Earth's ecosystems is called the
the primary source of energy for hydrothermal vent communities is
oxidation of hydrogen sulfide in the vent water
while on a walk through a forest, you notice birds in the trees, earthworms in the soil, and fungi on plant litter on the forest floor. Based on your observations, you conclude that each of these organisms occupies a different
Rachel Carson's book , Silent Spring, deals with the
environmental effects of pesticides
the level of ecologic organization that incorporates abiotic factors is the
the immediate results of the widespread use of pesticides and fertilizers included ______, but long-term results included ______.
dramatic increases in crop yields, the evolution of pest resistance
in many dense forests, plants living near the ground level engage in intense competition for
which of the following environmental factors usually has the greatest direct effect on an organism's rate of water loss by evaporation?
the reason that the pronghorn antelope is not found outside North America is most likely that
it has never dispersed beyond this region
the adaptations of pronghorns
to abiotic and biotic factors by natural selection are highly successful in open country
changes in the seasons are caused by
the tilt of Earth's axis toward or away from the sun
in terms of global air circulation, the tropical regions are the regions where air
rises and cools, dropping rain
the greatest annual input and least seasonal variation in solar radiation occurs in the
most of the world's deserts are located at latitudes where
cold, dry air moving toward the poles descends
a whale in the middle of the Atlantic Ocean is in which oceanic zone?
except near hydrothermal vents, the communities of the oceanic aphotic zone get their energy mainly from
organic matter sinking from the photic zone
phytoplanktons ar the major photosynthesizers in
the ocean photic zone
an economist monitoring the number of wolves in a wild refuge over a 5-year period is studying ecology at which level?
freshwater and seawater mix in a(n)
why is the runoff from fertilized agricultural fields,even if free of pesticides, often harmful to the ecosystems of temperate lakes?
the runoff causes a surface algal bloom, which reduces the lake's oxygen by cutting off the sunlight and fouling the water with dead organic matter
species in widely separated biomes often appear display similar characteristics because of
which of the following statements about biomes, the major terrestrial ecosystems covering the Earth, is true?
the major factors affecting the distribution of biomes are temperature and rainfall
which of the following statements about tropical forests is true?
in tropical regions with distinct wet and dry seasons, tropical deciduous trees and shrubs are common
the kind of vegetation in a tropical rain forest is generally determined by the amount of
the major reason for tropical deforestation is
people clearing forests to open up land for agriculture
the dominant herbivores in savannas are
which of the following options correctly pairs a biome and its characteristics?
tundra=very cold winters; only the upper layer of soil thaws during the summer
chaparral vegetation occurs around much of the central valley of central and southern California. this biome is very similar to that found
in the Mediterranean region
most of the best agricultural soils in the United States are found in areas that were formerly
in which of the following biomes would you expect to find the highest abundance of large, grazing animals?
which of the following biomes is dominated by coniferous trees adapted to surviving long, harsh winters and short, wet summers?
coniferous forests are dominated by
spruce, pine, fir
the most complex and diverse biome is
tropical rain forest
which of the following tundra features would be found at the top of the Andes mountains in Ecuador?
fierce winds and frigid nights
which of the following factors is fundamentally responsible for the character of arctic tundra soils?
which of the following has the greatest impact on the global water cycle?
human destruction of forests
a community is composed of
potentially interacting populations of different kinds of organisms
one reason it is important to understand community ecology is
to aid in conservation of endangered species
when a crocodile eats a fish, the interspecific interaction between the two could be expressed as ______ for the crocodile and ______ for the fish.
an owl and a hawk both eat mice. which of these terms describes the relationship between a hawk and an owl?
when two different populations in a community benefit from their relationship with each other, the result is called
which of the following is an example of predation?
a hawk swooping down quickly to capture, kill, and eat a prairie king snake
in an ecosystem, you would expect to find interspecific competition between
populations of two species that occupy the same niche
dinoflagellates are important to coral and coral-dwelling animals because they
produce energy that is used by coral animals through photosynthesis
one mechanism that prey populations evolve to avoid predation is
the bacteria that cause tooth decay have a ______ relationship with humans.
in addition to environmental factors, community composition of plants can be severely compromised by
parasites and pathogens
on Earth, most organic molecules are produced by
which of the following statements regarding food webs is true?
several species of primary consumers may feed on the same species of producer.
we expect that a keystone species that is a predator will
maintain the species diversity in a community
the number of species in a community is called the
within an ecosystem a tree is a
the sum total of a population's use of the biotic and abiotic resources of its habitat constitutes its
a series of reciprocal adaptations in two species defines
in a hypothetical food chain consisting of grass, grasshoppers, sparrows, and hawks, the grasshoppers are
non-native species that are introduced in new environments, spread far beyond the original point of introduction, and cause damage are called
biological control is defined as
the intentional release of a natural enemy of a pest population
the flow of _____into ecosystems occurs in one direction only, while ______ are recycled within the ecosystem itself.
in a food chain consisting of phytoplankton --> zooplankton --> fish-->fishermen, the fisherman are
the primary decomposers of a community are called
when a New England farm is abandoned, its formerly plowed fields first become weedy meadows, then shrubby areas, and finally forest. this sequence of plant communities is an example of
in an ecosystem, about how much of the energy in producers will be available to secondary consumers in this ecosystem?
given that CO2 is produced by respirations, why does the amount of CO2 in the atmosphere remain relatively constant?
CO2 is converted in photosynthesis to carbohydrates
which of the following substances is cycled between organic matter and abiotic reservoirs?
carbon mainly cycles between the biotic and abiotic worlds through the processes of
respiration and photosynthesis
which of the following statements about the phosphorus cycle is true?
phosphorus is cycled almost entirely within the soil, rather than transferred over long distance via the atmosphere
which of the following statements about the nitrogen cycle is true?
the nitrogen cycle requires different types of bacteria
which of the following represents a step in the nitrogen cycle?
nitrogen-fixing bacteria convert atmospheric nitrogen to ammonia
denitrifying bacteria convert ______ to _____.
nitrates, nitrogen gas
in experimental studies conducted at the Hubbard Brook Experimental Forest, it was found that
water runoff increased in the deforested areas
eutrophication of a lake could occur if
phosphate-rich detergents were dumped into the lake.
the primary goal of conservation biology is to
counter the loss of biodiversity
approximately _______ living species have been named and described.
the current rate of extinction may be as much as ______ times higher than at any other time in the past 100,000 years.
the genetic diversity within and between populations of a species
in the 2,000 years that humans have lived on Madagascar, the island has lost approximately ______ of its native species
currently, the single greatest threat to biodiversity is
habitat destruction due to humans
the three greatest current threats to biodiversity, in order starting with the greatest, are
habitat destruction, the introduction of invasive species, and overexploitation
deplete the ozone layer
which of the following is likely consequence of the thinning of the ozone layer?
increases in skin cancer
large costal dead zones depleted of oxygen are primarily caused by
the increase in the concentration of a substance in the tissues of organisms as it is passed up a food chain is called
the top predators are most severely affected by pesticides such as DDT or manufacturing toxic substances such as PCBs, because they
consume prey in which pesticides or toxic substances are concentrated
approximately _____ of the prescriptions dispensed by US pharmacies contain substances drived from plants
global warming is the result of
rising concentration of greenhouse gases
average global temperature has risen _____ over the past 100 years.
0.8 degrees Celsius
the increase in global temperature resulting from the greenhouse effect is primarily due to
CO2 slowing the escape of heat from Earth
CO2 flooding into the atmosphere is absorbed by _____ and converted into biomass.
an organism's responses to climate change that result in phenotypic variation is called
are likely to exhibit low levels of genetic diversity
some populations may avoid extinction as the climate changes, especially those with high genetic variability and short life spans, through
movement corridors are
strips or clumps of habitat that connect isolated fragments of habitat
which of the following statements about movement corridors is true?
movement corridors can connect otherwise isolated habitat patches
often results from human activities
species found in only one place on Earth are called ____ species.
about one-third of all animal and plant species are concentrated on ______ of Earth's land.
the greatest challenge of facing the zoned reserve systems of Costa Rica is
the growing human population
which of the following statements about zoned reserves is incorrect?
the areas surrounding a zoned reserve are not to be used to support human populations
which of the following statements about protected areas is incorrect?
we now protect 25% of the land areas of the planet
the Yukon to Yellowstone Initiative is a plan to
connect parks in the United States and Canada with protected corridors where wildlife can travel safely
with limited sources, conservation biologists need to prioritize their efforts. of the following choices, which should receive the greatest attention for the goal of conserving biodiversity?
a declining keystone species in a community
the aspect of conservation ecology concerned with returning degraded ecosystems (as nearly as possible) to their predegraded state is
using living organisms to clean up polluted ecosystems is know as
the Kissimmee River Project is an
attempt to restore the natural wetlands associated with the Kissimmee River
the Kissimmee River Project is intended to
increase biodiversity of the region
depends on continued research and application to increase and apply knowledge to the biosphere