chapter 14 ecology and evolution ( population dynamics through space and time)

what are some reasons/factors that populations will experience fluctuations

availability of resources, predation, competition, disease, parasites, and climate

what is overshoot

when a population grows beyond its carrying capacity; often occurs when the carrying capacity of a habitat decreases from one year to next

what is die off and when do they occur

a substantial decline in density that typically goes well below the carrying capacity

• die-offs often occur when a population overshoots its carrying capacity

Answer: Which of the following statements
regarding population fluctuations is correct?
a. Some populations never fluctuate in size.
b. Population overshoots can be caused by seasonal
variations in food abundance.
c. Populations that have higher growth rates tend to
fluctuate less.
d. Small-bodied organisms have particularly stable
populations.

b. Population overshoots can be caused by seasonal
variations in food abundance.

what are population cycles

regular oscillation of a population over a longer period of time

when can cyclic populations occur

among related species and across large geographic areas

what are damped oscillations

a pattern of population growth in which the population initially oscillates but the magnitude of the oscillations declines over time

what is a stable limit cycle

a pattern of population growth in which the population continues to exhibit large oscillations over time

when may delayed density dependence occur

because the organism can store energy and nutrient reserves, also it can occur when there is a time delay in development from one life stage to another

what is the deterministic model

a model that is designed to predict a result without accounting for random variation in population growth rate

what is the stochastic model

a model that incorporates random variation in population growth rate; assumes that variation in birth and death rates is due to random chance

what is demographic stochasticity

variation in birth rates and death rates due to random differences among individuals

environmental stochasticity

variation in birth rates and death rates due to random changes in the environmental conditions

Question: Which is an example of demographic
stochasticity?
a. Extreme weather variation causes bird populations to
suffer more in some years than others.
b. Predators kill disproportionately more juveniles than
adults in a prey population.
c. In a given year, some individuals may produce many
offspring while some produce none at all.
d. Human coastal development wipes out some shorebird
colonies, but leaves others intact.

c. In a given year, some individuals may produce many
offspring while some produce none at all.

what is the definition of the metapopulation

a set of local populations linked by dispersal

in a metapopulation, each subpopulation has its own independent ___ and ___

birth rate, death rate

what is the source sink model

recognizes differences in quality of suitable habitat patches

• source= high quality

• sink= low quality

what is the landscape model

it considers effects of differences in the habitat matrix

• the quality of a habitat patch can be affected by the nature of the surrounding matrix

• some matrix habitats are more easily transversed than others

what is the rescue effect

when dispersers supplement a declining subpopulation and thereby prevent it from going extinct

• less isolated patches are more likely to be rescued and are also more likely to be colonized