Population Size
In a particular environment there is plenty of food, water, cover, and space to support a large population of pheasants, but a larger quantity of predators are introduced. The predators become the _______ for pheasants in that environment.
c. limiting factor
Which of the following factors would have the smallest impact on a population's size?
c. the variety of organisms
Identify the abiotic limiting factor from the choices below.
c. water
Which of the following factors would have the least effect on the carrying capacity of an ecosystem?
d. competitive exclusion
Migration is _______.
d. the seasonal movement of organisms between locations
A population distribution shows _______.
d. where and in what arrangement organisms are located
Which of the following species is an R-selected species?
b. Mosquitoes
Which of the following statements about population distribution is not true?
b. Population distribution applies only to animals.
How does population density differ from population size?
b. Population size is the total number of organisms, while population density is the total number of organisms within a given area.
When two species compete for the same ecological niche, they cannot coexist because they are competing for the exact same resources. One species is always slightly better adapted for the niche than the other, so over time the disadvantaged species will either go extinct or shift to a different ecological niche. This situation highlights the concept of _______.
b. competitive exclusion
Identify the biotic limiting factor from the choices below.
b. vegetation
Which of the following statements is true?
c. The available space in an ecosystem is an abiotic limiting factor.
Lions live in groups called prides. Lion populations would most likely fall in which category of population distribution?
c. clumped
A population's distribution can be even, clumped, or random.
true
R-selected species have a short life span and an early reproduction cycle.
true
Why is it important to look at the combination of birth and death rates when considering population size?
It is important to look at the combination of birth and death rates, because a high birth rate alone will not lead to a large population size. If a population has a high birth rate, but has an even higher death rate the population size will decrease. Conversely, if a population has a low birth rate, but has an even lower death rate the population size will increase.
How does population density differ from population size?
Population size looks at the total number of organisms in a population. Population density, however, looks at the total number of organisms in a given area. A population with a small number of organisms can have a higher population density than a larger population if they live in a very small area. For example, the overall population of the United States is greater than the population of Japan, but Japan's population density is greater.
What are the biotic and abiotic factors that limit population size?
The biotic and abiotic factors that limit population size are space, food, shelter, water, climate, competitive exclusion, and temperature.
How do the biotic and abiotic limiting factors of an ecosystem determine its carrying capacity?
The carrying capacity of an ecosystem is the total number of organisms it can support. Biotic and abiotic limiting factors such as the amount of available space, food, water, and shelter determine how many organisms can live within an ecosystem. An ecosystem with a high availability of these limiting factors will be able to support more organisms and will have a greater carrying capacity.
What are the possible impacts on the limiting factors that determine population size of an extended period of lower than normal rainfall?
The population's resource supply will be directly affected. The amount of water available will be less than usual, which will in turn affect the food supply of different animals. This will likely cause the birth rate to decrease and the death rate to increase, which will reduce the population size. In order to overcome the effects of the drought, animals may migrate temporarily or perhaps emigrate to new locations where water is more readily available.
Which of the following statements about tolerance range is true?
a. Tolerance range is different for different organisms.
Which of the following conditions would lead to a small population size?
a. a low birth to death ratio
Which of the following is an example of an even population distribution?
a. corn planted in a field
Orange trees planted in an orchard would most likely fall in which category of population distribution?
a. even
When population growth increases in an area, what is happening to the birth rate and age structure of that population?
a. increasing birth rate with a greater number of young organisms
A high birth to death ratio leads to smaller populations.
false
