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most commonly individuals show a ___ distribution within their habitat
clumped
the rate at which population size grows or declines depends on the rate of
births, deaths, immigration, emmigration, and available resources
Suppose 200 fish are marked and released in a pond. The following week, 200 fish are caught and 100 of them have marks. There are about ___ fish in this pond
400
For a given species, the maximum rate of increase per individual under ideal conditions is its
biotic potential
___ is a density-independent factor that influences population growth.
harsh weather
Species that live in unpredictable habitats are more likely to show traits that are favored by
r-selection
When human or animal predators target the largest members of a prey population, prey individuals who ___ are at a selective advantage
mature sexually while small
Compared to the less developed countries, the highly developed ones have a higher
resource consumption rate
All members of a cohort are the same
age
The ecological footprint of a person in the United States is about that of a person in India.
nine times
The demographic transition model predicts a decline in population during the ___ stage
postindustrial
A population in which the total fertility rate exceeds the replacement fertility rate is
increasing in size
The type of physical environment in which a species typically lives is its
habitat
___ can lead to resource partitioning
interspecific competition
By a currently favored hypothesis, species richness of a community is greatest when physical disturbances are of ___ intensity and frequency.
intermediate
With ___ one species evolves to look like another.
mimicry
Growth of a forest in an abandoned corn field is an example of
secondary succession
Species richness is greatest in communities ___
near the equator
If you remove a species from a community, the population size of its main ___ is likely to increase
competitor
___ steal parental care
brood parasites
The oldest established land communities are
in the tropics
Biological control of pest species
uses natural enemies
In most ecosystems, the primary producers use energy from __ to build organic compounds
sunlight
Organisms at the lowest trophic level in a tallgrass prairie are all
autotrophs
All organisms at the top trophic level
would be at the top of an energy pyramid
Primary productivity is affected by
nutrient availability, amount of sunlight, and temperature
Efficiency of energy transfers in aquatic ecosystems is typically higher than in land ecosystems because
algae do not make lignin
Most of Earth’s freshwater is
frozen as ice
Earth’s largest carbon reservoir is
sediments and rocks
Carbon is released into the atmosphere by
burning fossil fuels
Greenhouse gases
slow the escape of heat energy from Earth into space, are produced by natural and human activities, and are at higher levels than they were 100 years ago
The ___ cycle is a sedimentary cycle
phosphorous
Earth’s largest phosphorus reservoir is
sedimentary rock
Plant growth requires uptake of ___ from the soil
nitrogen and phosphorous
Nitrogen fixation converts _ __to ___ .
nitrogen gas; ammonia
Burning fossil fuel releases ___ into the air.
carbon dioxide; nitrous oxide
the Northern Hemisphere is most tilted toward the sun on the
june solstice
Warm air _ __and it holds ___ water than cold air
rises; more
a rain shadow is a reduction in rainfall
on the inland side of a coastal mountain range
___ have a deep layer of nutrient-rich topsoil.
grasslands
Biome distribution depends on
climate, elevation, and soils
grasslands most often are found
in interior of continents
permafrost underlies
arctic tundra
Chemoautotrophic bacteria and archaea are the main primary producers for food webs
at hydrothermal vents
What biome borders boreal forest to the north?
tundra
Unrelated species in geographically separated parts of a biome may resemble one another as a result of
morphological convergence
Passenger pigeons were driven to extinction
by overharvesting
An ___ species has population levels so low it is at great risk of extinction in the near future
endangered
Sulfur dioxide released by coal-burning power plants contributes to
acid rain
As a result of ___ an old animal usually has more pollutants in its body than a young one.
bioaccumulation
With biological magnification, a ___ will have the highest pollutant load.
top-level consumer
An increase in the size of the ozone hole would be expected to
increase skin cancers
Global climate change is causing
glacial melting
A highly threatened region that is home to many unique species is a(n)
biodiversity hot spot
Biodiversity refers to
genetic, species, and ecosystem diversity
Restoring a marsh that has been damaged by human activities is an example of
ecological restoration
Note 
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