Bio ch.42

Which of the following accurately compares density dependent (DD) factors and density independent (DI) factors?

DD: mortality increases with population size; DI mortality remains unchanged with population size

Which of the following can be affected by density dependent factors?

Death rates and/or birth rates

According to the logistic growth model, when the number (N) of individuals in a population approaches its carrying capacity (K), the population's growth rate should approach (and eventually become) which of the following?

zero

When a population's size does not change over time, the population's growth rate is

zero

The current growth rate of the human population is about

1.1% per year

What are r-selected species?

Species with high rate of per capita population growth, but poor competitive ability

In which of the following situations would a population exhibit exponential growth?

A population which reaches a new habitat with an abundance of resources

Choose the two examples of populations that might exhibit the Allee effect.

A sparsely distributed population, in which individuals have difficulty finding mates A population of a species that relies on large groups to deter predators

Which of the following accurately describe the following features of a typical K-selected species? A. LIfe span B. Mortality rate C. Size of offspring

A. Long; B. Usually low; C. Large

In some cases, the growth rate of a population can increase with population size. This is known as the

Allee

In some cases, the growth rate of a population can increase with population size. This is known as the effect.

Allee

What type of species would be expected to have a short life span, and an early age at first reproduction?

An r-selected species

Which of the following describe what happens to a population as it approaches its carrying capacity?

As a population approaches carrying capacity, resources are used up and growth rate declines.

Which of the following describes the role of density-dependent factors on population size?

Density-dependent factors regulate population size by limiting growth as density increases.

Select all reasons for human exponential growth.

Domestication of animals Improvements to public health Better sanitation practices

Which of the following accurately defines density-independent mortality factors?

Factors for which mortality remains unchanged in response to population density

Which of the following best describe how/when patterns of unrestrained or exponential growth of populations generally occur?

For short periods of time

Which of the following are K-selected life-history traits seen in humans?

High degree of parental care Late reproduction Small brood size

What does rN represent in the logistic growth model?

Intrinsic rate of increase

Our ecological footprint can help estimate carrying capacity because of which of the following?

It is an indication of whether we are using more productive land than the earth can sustain over time.

Which of the following best describes how the human population is growing?

It is growing exponentially because of advancements in technology.

The current growth rate of the human population is 1.1% per year. What does this growth rate mean in terms of the doubling time of the human population?

It will still take relatively little (about 60 years) for the human population to double

A population with a per capita growth rate declining to zero would begin to approach its

carrying capacity

The sigmoidal growth curve in this figure represents which of the following models of population growth?

Logistic growth

Which of the following describes logistic growth?

Logistic growth occurs when the population is restricted by some limiting factor.

Humans exhibit which of the following K-selected adaptations?

Long life span

Which of the following best describes the result of unchecked exponential growth?

Population explosion

Which of the following accurately describe why populations cannot grow exponentially forever?

Population growth is limited by the amount of available resources.

Characteristics of r-selected species include which of the following?

Rapid development High reproductive rate Early reproductive age

Which of the following assumptions would be made when modeling exponential growth?

Space is available. Water is unlimited. Food is plentiful.

Which of the following accurately describes an ecological footprint?

The amount of land required to support an individual throughout their lifetime

How does the ecological footprint of an individual in the USA compare to that of someone in a developing country, such as, for example, India?

The ecological footprint of someone in the USA is much larger.

In the hare-lynx predator prey system, what happens if hares are provided with abundant food, but the predators are still allowed to harvest hares freely?

The two populations continue changing in a cyclic way

If the average ecological footprint per person that Earth can sustain is about 2 hectares and humans exceed that, an ecologist would infer which of the following?

We were in an ecological deficit and we would reach carrying capacity faster.

When scientists set up experimental plots where they controlled the availability of food for hares and the presence/absence of predators (lynx) they determined that

both food shortage and prey shortage are important in determining the cycles of hares and lynx.

A reduction in the amount of available resources in an environment would cause the carrying capacity to

decrease

The human growth rate is currently Blank 1Blank 1 1.1 , Incorrect Unavailable due to increased family planning methods, and the increase economic power and social status of women.

decreasing

A population's growth would be limited as the density of that population increases because of - factors.

density dependent

Density- factors are those whose influence varies with population density, whereas density- factors are those whose influence is unaffected by population size.

dependent independent

The aggregate total of productive land needed for survival is called a person's

ecological footprint

Rapid population growth occurring when per capita growth rate remains above zero is called growth.

exponential

growth models assume resources are unlimited.

exponential

In this figure, line A represents growth, whereas line B represents growth.

exponential logistic

Population growth cannot continue at the maximum rate forever because of the limited amount of available in the environment. Population growth slows and stabilizes at a size called the because of these limits.

resources carrying capacity

Population cycles for the Snowshoe hare are regulated by two factors,

food predators

Mortality factors whose influence is not affected by changes in the number of individuals per unit are called density- factors.

independent

-selected species are those with relatively stable populations adapted to existing at or near their carrying capacity.

k

selected species exhibit high per capita growth rates with poor competitive ability, whereas -selected species exhibit low per capita growth rates with strong competitive ability.

k r

The number of offspring produced during a single reproductive event

logistic

The pattern in which population growth slows down as it approaches the carrying capacity is termed growth

logistic

A population is a bar graph displaying the number of people in several age categories.

pyramid

selected species are those with unstable populations that have a high rate of per capita population growth.

r

In the logistic growth model, (K-N)/K represents

the fraction of the carrying capacity that is still unused.

The carrying capacity is defined as

the maximum number of individuals that an environment can sustain.

In most human population pyramids,

the number of older females is disproportionately large compared with the number of older males.

Rapid population growth in developing countries has had an important effect: it has increased the gap between

the rich and the poor.