APE Chapter 6&7
Terms in this set (44)
which type of population distribution can enhance protection from predators?
when individuals are found to be distributed evenly throughout an ecosystem it is often because
they are territorial
animals are sometimes randomly distributed across an ecosystem within a population because of
the fact that resources are not limiting
which of the following is true?
some populations grow without restrains as long as resources are not limiting, the size of some populations tends to remain relatively constant over time, in some populations size fluctuates in a cyclical pattern, and population size may vary sporadically in response to environmental changes (E. all of the above)
if a population of 100 birds increases to 120 birds the following year, growth rate, r=___
a population of river otters has a growth rate of (r) of 0.2 per year. If the population starts out with 50 individuals and there is no migration, how many would you expect after one year; after two years?
at the start of a study, there were 200 spotted salamanders in an old-growth forest patch in western oregon. Over the next year a biologist tracking the salamanders saw that 25 new salamanders hatched and 5 died. Thus r for this year was
an ecosystem's carrying capacity for a population is determined by all the following factors except
climatic events, such as tornadoes
some predators feed preferentially on the most abundant prey. this type of predation is
an exotic species is one which ___ an ecosystem
is rare in
rapid growth may be temporarily be observed in a population in response to all of these EXCEPT
introduction of a new parasite
A laboratory experiment followed the growth of a flour
beetle population over time. At first the population
increased dramatically, but later the growth slowed and
the population size leveled off. Although food (wheat
flour) was still abundant, the flour beetles resorted to
eating their own eggs when population densities got high.
What can we conclude about cannibalism in this species?
It is a density-dependent means of population control.
During the winter of 1999, minimum temperatures did not get much below freezing in an Oregon pond, and the following summer large mosquito populations were observed. In the winter of 2000, frost came early, and most ponds froze for 3 months. In the following summer, very low mosquito populations were observed. This is an example of
A study conducted in the laboratory used wasps as predators and bean weevils as prey. The wasps lay their eggs on weevil larvae, which provide food for the newly hatched wasps. What would be the most likely hypothesis for the outcome of this experiment?
The predator population increased and decreased slightly later than the prey population
If you were studying the niche of a species of bird, you might study
the food it eats, its predators, the temperature it needs to survive, and the places where it builds its nests
if similar species each occupy a smaller niche when they live together than they would if they live alone, that are said to be
the concept that two species cannot occupy the same ecological niche is called
scientists visiting a remote island find two species of birds that appear nearly identical except for bill size. the species with the larger bill eats larger seeds, and the species with the smaller bill eats small seeds. according to genetic evidence, the two species are extremely closely related to each other. which of the following the most likely explanation of the different bill sizes in these species?
competition between the two species resulted in resource partitioning
Two species of buttercup can be found in the same field in South Dakota; but they emerge at different times: on species emerges and flowers in early spring, and the other species does not emerge till late summer, after the first species has set seed. This is likely to be an example of
In his 1961 paper, "The Paradox of the Plankton," ecologist G. E. Hutchinson noted that several species of algae coexist, sharing the same few mineral nutrient resources in homogeneous open-water systems. Because there is little chance of resource partitioning and niche differentiation in such a situation, the paradox of their coexistence is an apparent violation of:
the competitive exclusion principe
over the past century, sagebrush has dramatically expanded its range over the colorado plateau's grasslands. this had been attributed to the overgrazing of the area's grasses by cattle and sheep. this example indicated that
the range of sagebrush is normally limited by competition with grasses
if an insect eats the lettuce seedlings in our yard, it is acting most like a
which of the following best describes the reason why bright coloration is an effective defense against predators
the predator can see the color and, either through neutral selection or learning, avoid the prey
which of these might a predator use to better enable it to catch its prey
the term "symbiosis" includes which of the following relationships between organisms of two different species?
mutualism, commensalism, and parasitism
what characterist best distinguishes predators from parasites?
parasites live on or within their prey
a species that plays a major role in determining the structure of its ecological community is
a keystone species
which of the following is NOT true of the general pattern of succession from a recently disturbed terrestrial site to stable, self-sustaining forest community?
total biomass tends to decrease
if the growth rate r of a population is positive and remind constant, the number of people added to the population
increases each year
the most critical factor in controlling human population growth is
decreasing the average number of births per woman
the total fertility rate is an estimate of
the number of children each woman in a population will have
which factors would NOT influence the size a population reaches over time?
distance traveled by migrant
to determine the number of individuals who will be added to a population in a specific time we multiply the growth rate r by the
original population size
under which of the following conditions would a population grow?
the birth rate exceeds the death rate and there is no immigration or emigration
the human population is currently following roughly a J-shaped curve. this means that the population is growing
developing countries tend to have a(n) ___ age structure diagram
if a population's age structure diagram looks like a pyramid, the population
populations with relative rectangular shaped age structure diagram have ___
a smiliar number of individuals in each age group
populations whose age structure diagrams are narrower at the bottom than at the top have
a declining population
if women delay child bearing,
the growth rate will decrease
if a country with a high population growth rate quickly reduces its growth rate to 0%, its population would
continue to grow for many years, then level off
There are about 6.8 billion people in the world and about 11.4 billion usable hectares. Currently, the population of the United States has an ecological footprint of about 9.0 hectares per person. If all people in the world were to live at the level of consumption found in the United States, the population of the world would have to ____ in order to support them
reduce to less than one-fifth of the current levels
using the rule of 70, a population growing at 10% would double in
population size can be estimated using the formula