Biology Ch 36

a group of individuals of a single species that occupy the same general area

the number of individuals of a species per unit area or volume (ecologists use sampling techniques to estimate)

the way the individuals are spaced within their area

when individuals are grouped in patched ex. a school of fish (most COMMON in nature, results from unequal distribution of resources in the environment)

when individuals are dispersed in an even manner ex. king penguins (results from interactions between the individuals of a population)

when individuals are spaced in an unpredictable way ex. dandelions (varying habitat conditions and social interactions make this dispersion patter RARE)

plots survivorship as the proportion of individuals from an initial population that are alive at each stage

track the chance of an individual in a given population surviving to various ages

What are the 3 types of dispersion patters?

What is the relationship between a population and a species?

What dispersion pattern would you predict in a forest population of termites, which live in damp rotting wood.

How dies the chance of survival change with age in organisms with a Type III survivorship curve?

average contribution of each individual to population growth

an idealized picture of unregulated population growth; the rate of population increase under ideal conditions, no restrictions on the organism to live, grow, and reproduce

environmental factors that restrict population growth

a description of idealized population growth that is slowed by limiting factors as the population size increases

the maximum population size that a particular environment can sustain

In logistic growth at what population size is the population increasing most rapidly? Explain why.

declining birth rates and rising death rates in response to increasing population density (increased density causes population grown rate to recline by reducing birth rate and/or increasing death rate

List some of the factors that may reduce birth rate or increase death rate as population density decreases.

Produce few offspring but take good care of each one increasing the likelihood that they will survive to maturity (eg humans - high survivorship)

Produce a medium amount of offspring and cares little for each one with survivorship constant over the life span - no more vulnerable at one stage of life than another (straight line eg squirrels, lizards, rodents)

Produce many offspring and takes care of none with low survivorship for the very young followed by high survivorship for those few individuals that live to a certain age (eg oysters, nile perch produce 16 million eggs but most die young)

How would a population grow rapidly?

What is the shape of exponential growth on a graph?

What is the equation for the exponential growth model?

What is the equation for the logistic growth model?

What are the 3 types of population cycles?

harvesting a resource as a level which can be sustained without population decline

have same effect on population growth regardless of density

the traits that affect an organism's schedule of reproduction and death make up its _______________

In one experiment, increasing food supply to hares increased their population density, but the population continued to show cyclic collapses. What might you conclude from these results?

harvesting a resource without damaging it

Explain why managers often try to maintain populations of fish and game species at about half their carrying capacity.

a shift from zero population growth in which birth rates and death rates are high but roughly equal to zero population growth characterized by low birth and death rates

used to predict a populations future growth; it is the number of individuals in different age groups

in a population in which r = 0, the continuation of population growth as girls in the reproductive age group reach their reproductive years [an age structure with a broad base has a high proportion of children and a high birth rate because on average, each woman is substantially exceeding the replacement rate of two children per couple. When this occurs, the proportion of women of childbearing years increases and now a situation called __________________ exists. }

One life history pattern is typified by small-bodied, short lived animals that develop and reach sexual maturity rapidly, have a large number of offspring, and offer little or no parental care AND/OR plants like dandelions that produce thousands of seeds. Ecologists hypothesize that selection for this set of life history traits occurs in environments where resources are abundant permitting exponential growth. What is this called and why?

One life history pattern is typified by large-bodied, long lived animals that develop slowly and produce few but well cared for offspring AND/OR plants like coconut palms that produce few seeds that are well stocked with nutrient rich material (the plant's version of parental care). Ecologists hypothesize that selection for this set of life history traits occurs in environments where population size is near carry capacity. What is this called and why?

During the demographic transition from high birth and death rates to low birth rates and death rates, countries usually undergo rapid population growth. Explain why.

an estimate of the amount of land required to provide the raw materials an individual or a nation consumes including food, fuel, water, housing, and waste disposal; it is one approach to understanding resource availability and usage

the study of how and why population changes

the average contribution of each individual to population growth

the curve is known as the logistic growth model curve, idealized population growth that is slowed by limiting factors as the population size increase

dramatic fluctuations in density; rapid exponential growth that is typically followed by population falls to a minimal level (eg lemmings)

The rate at which a population increases in size if there are no density-dependent forces regulating the population

Refer to Module 36.3. Which type of survivorship curve would you expect to find in a population experiencing r-selection? K-selection?

harvesting should be done at a level that produces a constant yield without forcing a population into decline.

Point out an example of population momentum in figure 36.10