chapter 11 hw

Data indicate that we have overshot Earth's biocapacity -- its capacity to support us -- by 50%. We are using renewable natural resources 50% faster than they are being replenished. About how many times larger was the global ecological footprint in 2007 than it was in 1962?

2

How does population density of the black-throated blue warbler influence the birth rate at the New Hampshire site?

Birth rate decreases with an increase in population density.

Which processes increase a population's size?

Births and immigration

Which of the following statements about density dependence is FALSE?

Density-dependent factors alone cannot limit population growth.

Suppose that environmental conditions associated with El Niño resulted in a decreased survival in Jamaica during the winter but increased fecundity rates in New Hampshire. How would the population dynamics of the warbler species differ from what has been documented by S. Sillett and colleagues?

Density-dependent factors would control population growth.

Which of the following statements about density-independent growth is true?

Density-independent growth is also known as exponential growth.

Which factor does not affect a habitat's carrying capacity?

Genetic variation in the population

Which of the following statements about intraspecific competition is FALSE?

Growth rates of plants are only slightly influenced by intraspecific competition but are greatly depressed by the presence of interspecific competition.

Which of the following statements about a population experiencing logistic growth is true?

If N is greater than K, the population will shrink.

Which two statements are supported by the data in the graph?

In 1970, we began to overshoot Earth's capacity to support us. The global ecological footprint has generally increased over time, with brief periods of decrease.

Which two statements are supported by the graph?

Increasing female secondary school enrollment is strongly associated with reduced fertility rates. Cambodia and Guatemala have similar fertility rates but differ in their secondary school enrollment rates.

Black-throated blue warblers exhibit strong site fidelity. What is meant by this?

Individuals return to the same breeding and wintering locations each year.

Which of the following statements are true of a population at carrying capacity?

The birth rate equals the death rate. The population growth rate equals zero. The rate at which resources are used is equal to the rate at which they are supplied.

The logistic model effectively has two components: the original exponential term (rN) and a second term (1 − N/K). What is the function of the second term in this model?

The term 1 − N/K functions to reduce population growth as the population size approaches the carrying capacity.

True or false? Factors that determine the per capita rate of increase of a population include the age of breeding and the number of offspring produced each year.

True

Which of the following statements about competition is FALSE?

When competition occurs, individuals must directly interact with one another.

Compared to the control (red line), in which both sea urchins and limpets are present, removing limpets alone (blue line) did not have much effect. This might suggest that limpets have little effect on seaweed distribution. However, seaweed cover increased much more when both urchins and limpets were removed (purple line) than when only urchins were removed (green line). How might you explain this result?

When only urchins were removed, limpets increased in abundance and reduced seaweed cover.

Which of the following statements are true of logistic growth?

When the population reaches carrying capacity, it stops growing. & As the population approaches carrying capacity, it grows more slowly.

Under which of the following conditions would a population most likely experience exponential growth?

Young populations with few individuals.

If the beak length of G. fortis is typically 12% longer than the beak depth, what is the predicted beak length of G. fortis individuals with the smallest beak depths observed on Floreana and San Cristóbal Islands?

about 11 mm

Which of the following factors does not contribute to environmental resistance?

birth rate

This figures illustrates that territory size is positively correlated with

body size.

Scientists grew a population of yeast cells in a flask to which they provided a constant supply of nutrients. As the population of yeast cells increased, competition for the nutrients also increased. This caused the population to grow more slowly, until the rate at which the yeast cells used the nutrients was equal to rate at which the nutrients were supplied to the flask. Which of the three graphs shown in Part G best represents the growth of these yeast population?

graph a

A pair of coyotes colonized a large island where rodents (their prey) were abundant. At first the number of coyotes increased. But as the coyote population increased, competition for prey also increased and the coyote population grew more slowly. In some years, weather conditions killed many of the rodents, causing some coyotes to starve. In other years, weather conditions were favorable for the rodent poulation, allowing the coyotes to thrive, reproduce, and raise many pups. Which of the three graphs shown in Part G best represents the growth of this coyote population?

graph b

A female darkling beetle laid her eggs in a sack of corn meal. The corn meal was an excellent source of food for the beetle larvae (mealworms), and the beetle population quickly increased. After four months, the beetles had eaten all of the corn meal, and the adult beetles flew away to find new food sources. Which graph best represents the growth of the beetle population in the sack of corn meal?

graph c

What is one mechanism through which increased density may cause infant mortality in mammals?

high stress environments may reduce lactation

La Niña years are characterized by __________.

increased food supply for black-throated blue warblers

As a population approaches carrying capacity, environmental resistance __________.

increases

By organizing socially into a group, individual animals may benefit by

increasing access to a common food supply.

What does the orange graph line represent?

logistic growth

The individuals that disperse as a response to high population density are

mostly the younger members of the population.

Scatter plots like this one can help reveal whether two factors correlate to one another, and if so, whether their relationship is positive or negative. According to the graph, what type of relationship exists between a nation's total fertility rate and its female secondary school enrollment rate?

negative

Root competition among neighboring plants was studied by growing plants with their roots inside tubes of PVC pipes. Some tubes had holes of varying sizes, allowing their neighbors' roots to enter the tubes of a target plant. As the percentage of a target plant's tube open to neighbors' roots increased,

target plant biomass decreased and neighbor plant root biomass increased.

Neotropical migrants are songbirds that breed in __________.

temperate climates

The y-axis to the right represents ___________.

the level of resources available per capita

Which equation represents the logistic growth rate of a population?

ΔN/Δt=rmaxN*(K−N)/K