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