Population ecology Study Guide

parasite

an organism that lives in or on another living organism

an age structure diagram shows that the younger age groups contain many more individuals than oldest age groups. what does this indicate about the future of this population?

as they reach reproductive age, the population will increase

what might cause the carrying capacity for a given population to change?

fewer available resources due to disturbances (drought, floods)

what are density independent factors?

floods, drought, climate, fire

In the years prior to around 1500 A.D. the human population grew very slowly. what limiting factors kept the growth rate low?

food was scarce, transportation limited, and diseases were rampant

emigration

movement of individuals out of a population

true

the benefit of "owning" a territory is that the owner has exclusive use of the resources in the area

describe a population before and after the demographic transition.

the birth rate increases and exceeds the death rate

One spring, much rain and warmer than normal conditions caused the abundant growth of lush grasses where the caribou normally graze. how might this affect the wolf population?

the caribou population increases which is more food for the wolf population, the wolf population will increase

what will happen to the caribou herd when the wolf population decreases?

the caribou will increase because there are less wolf predators

True

the carrying capacity of the environment fluctuates

how is the exponential model different from the logistic model of population growth?

the exponential model grows at a rapid rate (J-curve) and in logistical the growth eventually stops or slows (S-curve)

F-cannot

the human population can continue to grow exponentially

predation

the interaction between two different organisms in which one captures and feeds upon the other

competition

the interaction that occurs between members of a population when they are trying to get the same limited resource

birth rate

the number of births in a population in a certain amount of time

density

the number of individuals per unit area

carrying capacity

the number of individuals the environment can support over a long period of time

dispersion

the spatial distribution of individuals within the population

big bang reproduction

the type of reproduction in which the organism produces all of its offspring in a single event

repeated reproduction

the type of reproduction in which the organism produces only a few offspring each year for several years.

population pyramids/age structure

this diagram shows the population of a country broken down by gender and age groups

T/F all populations are dynamic, meaning that they change in size and composition over time

true

T/F demography is the scientific study of human population

true

T/F if all conditions for growth are ideal, a population might grow exponentially

true

T/F in the U.S, families are now smaller than they were in previous decades

true

T/F organisms with low survival rates tend to have big-bang reproduction

true

what are some reasons that can explain the current exponential growth of the human population?

unlimited food supply, vaccinations, improved sanitation, increase life expectancy

what must be true in order for a population to grow exponentially?

unlimited food, water, no predation, no disease, shelter. conditions must be ideal

what conditions exist in the environment for population growth to occur as seen in Graph A (exponential).

unlimited resources

list the five characteristics that define and describe a population

1. geographic distribution, 2. density, 3. dispersion, 4. growth rate, 5. age structure

F- clumped

A population of wildflowers lives in a close group because they prefer a certain soil type and the light conditions that are present in the area. this dispersion pattern is called uniform.

the growth rate will be highest in a population that has: A. a higher percentage of young members B. a higher percentage of older members C. about the same percentage of members in each age group D. a high DR among young individuals

A. a higher percentage of young members

all of the following are density-independent factors for a rabbit population except: A. a bitter winter season B. the number of mountain lions in the area C. a summer drought D. a flooding river in the springtime

B the number of mountain lions in an area

in which one of the following would random dispersion most likely be observed? A. in an area where the food was located in one small area B. in a field of wildflowers whose seeds are blown by the wind C. in a population of animals that exhibit territorial behavior D. in a migratory herd of animals

B. in a field of flowers whose seeds are blown by the wind

what might be the result of a population growing larger than the carrying capacity? A. the BR will increase B. the DR will increase C. population growth will stabilize D. there will be an increase in immigration

B. the DR will increase

all of the following are important characteristics of a population except: A. geographic distribution B. density C. the number of parasites found in the same area D. dispersion E. growth rate F. age structure

C. the number of parasites found in the same area

which of the following occurs in a population with a negative growth rate? A. the population contains mostly younger individuals B. the BR is higher than the DR C. immigration is high, and emigration is low D. the DR is high compared to the BR

D. the DR is high compared to the BR

T/F the number of organisms of one species that the environment can sustain over a period of time is called exponential growth

F- carrying capacity

T/F high death rate and immigration are two factors that will decrease the size of a population

F- emigration

T/F worldwide, human populations have decreased exponentially over the past several centuries

F- increased

T/F if the number of organisms in a population is under the carrying capacity, death rates will increase

F- over

T/F a bullfrog population in a freshwater pond exhibits a Type II survivorship curve

F-Type III

exponential growth

Growth pattern in which the individuals in a population reproduce at a rapid rate. J-curve

immigration

Movement of individuals into a population

logistical growth

Population growth pattern that begins with rapid growth, and slows down as the environmental carrying capacity is reached; characterized by an S-shaped curve when graphed.

True

T/F a consequence of a population exceeding the carrying capacity of the environment may be higher than normal DR

F-developed

The "demographic transition" occurs in the developing countries of the world

death rate

The number of deaths in a population in a certain amount of time

geographic distribution

The range of the population.

survivorship curve

a graph that shows the likelihood of survival at different times in the life of an organism

population

a group of individuals of the same species living in the same general area

True

a popualtion is a group of individuals that belong to the same species thay live in the same area at the same time

density independent

affects all the population in the same manner regardless of size (severe weather, natural disasters)

growth rate

change in population size over time. calculate:(BR-DR= GR)

lists the types of dispersion

clumped, even, and random

what is the difference between density and dispersion?

density is the # of individuals living in a space dispersion is how grouped in that space

can two different populations have the same size but different densities? Explain

depends on the number of individuals in a given space.

how does the population growth in a "developing" country differ from the population growth in a "developed" country? Explain

developing is usually higher and has rapid population growth while developed countries have less births and slower population growth

What are density dependent factors?

disease, food, water, living spaces, competition

over time, how might the curve of Graph A (exponential) change.

eventually the available resources are depleted

what is the definition of clumped and why does it occur?

individuals are clumped closely together this happens due to availability of resources and protection from predators

what is the definition of even and why does it occur?

individuals are evenly separated from each other it occurs due to social interactions; trying to stay apart

what is the definition of random and why does it occur?

individuals are independent form each other seeds blowing in the wind

why might graph B (logistical) represent an eagle population along a river?

it has limited resources so the eagle population would reach carrying capacity.

explain how a decrease in the caribou herd will affect the wolf population?

less food, the wolf population will decrease

what effect will competition have on the caribou herd during a particularly bitter winter?

limited resources would make the caribou population decrease

density dependent

limiting factor dependent on population size (predation, limited resources, disease)

what is the relationship between the caribou and the wolf called?

predator-prey

give an example of how the population size of one species can affect the population size of different species?

predator-prey relationship