ISCI 173 || QUESTIONS WITH COMPLETE
SOLUTIONS.
Ecosystem correct answers a community of different species interacting with one another and
with their nonliving environment of matter and energy
3 components of an ecosystem correct answers autotrophs(producers),
consumers( herbivores, carnivores, and decomposers), abiotic matter(nonliving)
The relationship between individuals, populations, species, communities and ecosystems
correct answers many individuals make a population (one species), many populations make a
community (more than one species) , and many communities and abiotic factors make an
ecosystem.
Keystone species correct answers plays a critical role in the maintenance of specific
ecosystems
Habitat correct answers the space in which an organism lives; it is defined by the biological
requirements of each particular organism.
Niche correct answers the functional role an organism has in its surroundings; This term
includes all of the ways an organism affects other organisms and its physical surroundings
Natural Selection correct answers process of favorable species living and non-favorable
species dying out
Evolution correct answers a process of species changing over time
Natural Selection correct answers a theory of evolution
Communities correct answers an assemblage of plant and animal populations that live in a
particular area or habitat
Clumped correct answers Organisms are clustered in groups. Most common form of
distribution. Could reflect a patchy distribution of resources in an environment.
Random correct answers Individuals have an unpredictable distribution. Typical of species in
which individuals do not interact strongly.
Uniform correct answers organisms are evenly spaced over the area they occupy. This is
typical for species in which individuals compete for a scare environmental resource.
Limiting Factors correct answers Factors, both biotic and abiotic, that restrict where
organisms can survive.
Predation correct answers a kind of interaction in which one animal kills/eats another
organism.
, Competition correct answers a kind of interaction in which two organisms strive to obtain the
same limited resources.
Parasitism correct answers parasite benefits, host is hurt.
Commensalism correct answers one species benefits, the other is neither hurt nor helped.
Energy flow correct answers Sun, plants, primary consumer, secondary consumer
-sun, plants, decomposers,
H2O cycle correct answers evaporation, condensation, precipitation, runoff
Carbon cycle correct answers atmospheric CO2, photosynthesis, decay, back to atmosphere
Nitrogen cycle correct answers nitrogen in atmosphere, nitrogen-fixing bacteria, protein
plants, decomposers
Phosphorus cycle correct answers dissolved inorganic phosphate, uptake by plants, in plants,
then animals, then decomposed back to inorganic phosphate
Watershed correct answers the area of land where all of the water that is under it or drains off
of it goes into the same place.
General rule for energy transfer in a trophic chain/ pyramid correct answers 90% of energy is
lost between trophic levels
Human impacts on matter cycles correct answers burning fossil fuels releases large amounts
of carbon dioxide into the atmosphere, cutting down trees increases the amount of carbon
dioxide in the atmosphere
A dead zone and what causes it correct answers a place in the water where life does not exist,
caused by an increase in the number of plants and animals that are toxic due to an increase in
nitrogen and phosphorous resulting in lower oxygen concentrations
Ecological succession correct answers a series of regular, predictable changes in a
community structure over time (primary and secondary)
Climax communities correct answers the end result of succession
Tropical dry forest correct answers extensive dry periods, plants adapted to endure drought
Temperate Grassland correct answers hot summers, fires play key role, 60% plants
Savanna correct answers mostly grasses spotted with trees, trees fix nitrogen
Temperate Rainforest correct answers temperature and precipitation vary together, high tree
diversity
Tropical Rainforest correct answers equatorial, warm temperatures, soils are nutrient poor,
greatest diversity
