Ch. 40 - Pop Ecology

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 A Graph B Graph C

Graph B

In ecological terms, disturbance is an event such as a storm, fire, or human activity that changes a community, removing organisms and altering resource availability. Which of the following statements about the effects of disturbance is correct? A healthy community is in an equilibrium state of balance, with few disturbances. Disturbances can create patches of different habitats in a community. The effects of disturbance on a community are almost always negative.

Disturbances can create patches of different habitats in a community.

Aquatic biomes can be distinguished by chemical characteristics such as dissolved oxygen content and salinity and by physical characteristics such as water flow. Which five of the following statements about aquatic biomes are true? Estuaries are very productive and are used as breeding grounds by many species of fish. A freshwater organism permanently attached to the substrate would be unlikely to survive and reproduce in an estuary. Wetlands have slow water movement or no water movement and no turnover. Temperature drives water movement in some lakes. The lowest levels of dissolved oxygen in a stream are generally found in its turbulent headwaters. All wetlands have soils that dry out periodically. Tropical coral reefs generally exist in relatively shallow areas of the ocean.

Estuaries are very productive and are used as breeding grounds by many species of fish. A freshwater organism permanently attached to the substrate would be unlikely to survive and reproduce in an estuary. Wetlands have slow water movement or no water movement and no turnover. Temperature drives water movement in some lakes. Tropical coral reefs generally exist in relatively shallow areas of the ocean.

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 Graph B Graph C

Graph A

Review the graphs to determine whether the data support the four predictions. Graph A shows that the probability of hatching failure _______ later in the season. The data _______ Prediction #2. Graph B shows that the probability of hatching failure ______ at higher latitudes. The data ______ Prediction #1. Graph C shows that the probability of hatching failure is highest for ______ clutch sizes. The data ______ Prediction #3. Researchers were unable to test Prediction #4. This is because it was too difficult for volunteers to collect data on which eggs were ______

1. Graph A shows that the probability of hatching failure increases later in the season. The data support Prediction #2. 2. Graph B shows that the probability of hatching failure decreases at higher latitudes. The data support Prediction #1. 3. Graph C shows that the probability of hatching failure is highest for both the largest and the smallest clutch sizes. The data do not support Prediction #3. 4. Researchers were unable to test Prediction #4. This is because it was too difficult for volunteers to collect data on which eggs were laid earliest.

For a species with a Type II curve, less than ____% of individuals survive for 50% of the maximum life span. 0.1 0.5 1 10

10

According to this graph, the world population doubled between _______. 1850 and 1950 1900 and 1925 1930 and 1975 1975 and 2000

1930 and 1975

Which decade had, or is projected to have, the highest annual population increase? 1980-1990 1990-2000 2000-2010 2040-2050

1980-1990

Consider a population whose growth over a given time period can be described by the exponential model: dN/dt = rN. Select the correct statement about this population. A population with a positive value of r will grow exponentially. A population with an r of 0 will have no births or deaths during the time period under consideration. A population with an r of 0.1 will decrease over time.

A population with a positive value of r will grow exponentially.

What is represented by the distance between two vertical white gridlines on this graph? A population increase of 20 million A population increase of 2 billion A time span of 20 years A time span of 50 years

A time span of 50 years

Which of the following statements are true of logistic growth? Select all that apply. As the population approaches carrying capacity, it grows more slowly. The population grows at a steady rate. As the population approaches carrying capacity, it grows more rapidly. When the population reaches carrying capacity, it stops growing.

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

According to this graph, species that exhibit a Type III curve typically produce large numbers of offspring. Supported Not supported Cannot be determined from this graph

Cannot be determined from this graph

In this study, Hansen et al. used satellite imagery (Landsat) to map global-scale forest cover changes from 2000 to 2012 at high spatial resolution. Prior to this study, it was not possible to quantify the change in forest cover over time to this level of resolution. Why is this study important to so many countries? Hint: Turn on the "Results and conclusions" learning lens to highlight this study's significant findings.

Countries that lack access to initial forest cover data can utilize the data from this study to inform national forest monitoring and management strategies.

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 A Graph B Graph C

Graph C

What is represented on the x-axis of this graph? The percentage of surviving individuals, using a normal (non-logarithmic) scale Individuals' life spans as a percentage of the maximum life span for the species The percentage of surviving individuals, using a logarithmic scale The type of survivorship curve

Individuals' life spans as a percentage of the maximum life span for the species

One of the most important science practices is analyzing and interpreting graphical representations of data. Such representations and analyses can help bring out the meaning in the data. Analyze the graphs in Figure 3 of the online paper. Drag "True" or "False" to the end of each statement.

Indonesia has more forest management practices in place as compared to Brazil. False Based on the trendline, Brazil's rate of annual forest loss decreased each year. True Because the correlation value is negative, Brazil is gaining forest faster than it is losing forest. False Overall, Indonesia loses less forest per year than Brazil. True Indonesia lost an estimated 1,021 km2 more forest each year than the preceding year. True

Investigate the differences between these two types of population growth by completing the table below. Drag the labels onto the table to identify the characteristics of each type of population growth. Labels can be used once, more than once, or not at all.

J SHAPED CURVE type of growth: exponential growth habitat conditions: abundant resources growth rate: faster as population size increases maximum population size: no limit to population size example from part a: isabela island geckos S SHAPED CURVE type of growth: logistic growth habitat conditions: limited resources growth rate: slows as population size increases maximum population size: carrying capacity example from part a: daphne major geckos

Which statement accurately describes the potential effects of disturbance on species diversity? In many biomes, periodic disturbances may eliminate the dominant plants. Moderate levels of disturbance generally act to reduce species diversity within a community. Many species are well adapted to survive periodic disturbances.

Many species are well adapted to survive periodic disturbances.

The rate of human population growth is increasing. Supported Not supported Cannot be determined from this graph

Not supported

Figure 2 in the online paper illustrates changes in tree cover from 2000 to 2012 in four geographic areas around the world. Review the figure to familiarize yourself with the different colors depicted in the images. Match each region to the correct observation based on Figure 2 in the online paper.

Paraguay (Central South America) -this region shows almost no forest gain and a large portion of forest loss, most likely due to deforestation for the development of agriculture practices. Indonesia (southeast asia) -even with extensive areas of forest gain and combined gain and loss, this region experienced significant forest loss during the time period Arkansas (Southeast United States) -this region shows the most indications of managed forestry practices due to loss and subsequent gain of forest in the same areas Central Russia (northern asia) -this region shows distinct regions of forest loss and forest gain, most likely due to fire and fire recovery, respectively

Earth is not filled to the brim with elephants, or ants, or ferns, or geckos. What prevents a population from growing forever? Many different factors limit population growth. Some of these factors are density-dependent, and others are density-independent. Drag a label under each graph to indicate whether it shows density-dependent population regulation or density-independent population regulation. Labels may be used once, more than once, or not at all.

SOAY SHEEP density-dependent birth rate BRIDLED GOBIES density-dependent death rate DAPHNE MAJOR GECKOS density-dependent birth rate ISABELA ISLAND GECKOS density-independent death rate

This graph shows the effect of removal of urchins and limpets (alone and together) on seaweed cover. Select the statement that accurately describes the results shown in this graph. Sea urchins have a much greater effect than limpets in limiting seaweed cover. Removing only limpets increased seaweed cover dramatically. The lack of change over time in the control plots (with urchins and limpets present) shows that limpets and urchins have no effect on seaweed cover.

Sea urchins have a much greater effect than limpets in limiting seaweed cover.

During the 20th century, the human population increased from less than 2 billion to more than 6 billion. Supported Not supported Cannot be determined from this graph

Supported

From 1500 to 2010, the human population approximately followed the exponential growth model. Supported Not supported Cannot be determined from this graph

Supported

Total population size is projected to increase through the middle of the 21st century. Supported Not supported Cannot be determined from this graph

Supported

At 50% of maximum life span, how does survivorship for a Type I curve compare to survivorship for a Type III curve? Survivorship is equal for the two curves. Survivorship for a Type I curve is twice as great as survivorship for a Type III curve. Survivorship for a Type I curve is 100 times as great as survivorship for a Type III curve. Survivorship for a Type I curve is nearly 1,000 times as great as survivorship for a Type III curve.

Survivorship for a Type I curve is nearly 1,000 times as great as survivorship for a Type III curve.

Which of the following statements are true of a population at carrying capacity? Select all that apply. The birth rate equals the death rate. The population continues to grow at a constant rate. The rate at which resources are used is equal to the rate at which they are supplied. The population growth rate equals zero.

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

The graph shows the growth of a laboratory culture of Paramecium aurelia. Suppose that after 15 days, the researcher removed ~400 paramecia from the culture. How will the population growth rate (dN/dt) change as a result of this action? The growth rate of the Paramecium population will increase. The growth rate of the Paramecium population will not change. The growth rate of the Paramecium population will decrease.

The growth rate of the Paramecium population will increase.

What is represented by the vertical blue bars on this graph? The total population size The percentage increase in the population The number of people added to the population annually in each decade r, the per capita rate of increase

The number of people added to the population annually in each decade

The colors of the bars on the graphs indicate the life stage of the people in that age class. What does it mean if a bar is colored blue? The people in that age class are past reproductive age. The people in that age class have not yet reached reproductive age. The answer cannot be determined from the graphs. The people in that age class are of reproductive age.

The people in that age class are of reproductive age.

What prediction(s) can researchers make based on the egg-viability hypothesis? Select all that apply. The probability of hatching failure will be lower at higher latitudes. The probability of hatching failure will be higher later in the spring season. The probability of hatching failure will be higher for eggs laid later within a clutch. The probability of hatching failure will be higher in large clutches.

The probability of hatching failure will be lower at higher latitudes. The probability of hatching failure will be higher later in the spring season. The probability of hatching failure will be higher in large clutches.

Assuming that current trends continue, predict how the age structure of Canada in 2030 will likely differ from that in 2010. The proportion of the population made up of children (ages 0-15) will increase. The proportion of the population made up of adults of reproductive age will increase. The proportion of the population made up of older adults (65+) will increase. The answer cannot be determined from the graph.

The proportion of the population made up of older adults (65+) will increase.

Why is a percentage scale used for the x-axis rather than actual ages? Researchers don't know the maximum life span of the organisms. For any graph, the x-axis and y-axis must use the same units. This scale allows you to compare species with widely varying life spans on the same graph. The range of the actual ages would be too large to fit on the graph.

This scale allows you to compare species with widely varying life spans on the same graph.

In Canada in 2010, people between the ages of 45 and 54 made up the largest percentage of the population. What factor is most likely to have caused this bulge in the age pyramid? a surge in the birth rate after World War II ended in 1945 an increase in the death rate during World War I and the influenza epidemic of 1917 the increased availability of oral contraceptives in the 1950s and 1960s a decline in the birth rate during the Great Depression of the 1930s

a surge in the birth rate after World War II ended in 1945

Determine the correct order of events involved in seasonal turnover. Drag the labels onto the flowchart of seasonal turnover. Labels may be used once, more than once, or not at all.

a. surface water warms to 4 C and sinks b. water mixes, bringing oxygen to the bottom and nutrients to the surface c. warm surface water is separated from cooler bottom water by thermocline d. surface water cools to 4 C and sinks e. water mixes, bringing oxygen to the bottom and nutrients to the surface

Zones in lakes and oceans are delineated by depth, distance from shore, or light penetration. Different zones have different physical and chemical characteristics, such as temperature and salinity. Label the diagrams of zonation in lakes and oceans. Drag the labels to their correct targets on the diagrams below.

a.) freshwater plants may be rooted here b.) littoral zone c.) limnetic zone d.) alternately dry and submerged e.) extends to edge of the continental shelf f.) generally low nutrient levels g.) light penetrates here h.) no photosynthesis occurs here i.) benthic zone

In 2010, how many 25- to 29-year-old women lived in Niger? about 0.5 million about 1.0 million about 1.2 million about 0.5 billion cannot be determined from the graph

about 0.5 million

In Canada in 2010, which age classes contained the largest number of people? children between 5 and 14 adults between 25 and 34 adults between 35 and 45 adults between 45 and 54 adults between 55 and 64

adults between 45 and 54

Using satellite imaging, the researchers determined how forests change in different countries and biomes and were able to investigate major causes of forest change. One major goal of this large-area forest cover mapping was producing globally consistent analyses that are relevant and useful to local agencies interested in monitoring forest change for management and conservation. Select all the statements representing key results from this study. When comparing different biomes, this study found that the tropics were the only domain that showed an increasing rate of forest loss from 2000-2012. Brazil historically has had high rates of deforestation, but this study revealed that Brazil had the largest decline in annual forest loss. This study revealed drastic reductions in forest cover in southern Sweden and southwestern France due to severe weather events. This study revealed that subtropical forests had a low ratio of forest loss to gain due to forests being harvested as crops and replanted. Russia lost the most forest cover from 2000 to 2012

all the above

Which of the following factors does not contribute to environmental resistance? competition for space weather conditions competition for food environmental toxins birth rate

birth rate

Which of these is the largest terrestrial biome on Earth? tundra coniferous forest temperate broadleaf forest temperate grassland desert

coniferous forest

Which of these biomes is characterized by little rainfall? temperate broadleaf forest coniferous forest desert temperate grassland tropical rain forest

desert

A(n) _____ is a region where fresh water and salt water mix. benthic zone intertidal zone aphotic zone estuary photic zone

estuary

As a population approaches carrying capacity, environmental resistance __________. remains constant increases cannot be determined from the graph decreases

increases

What does the orange graph line represent? exponential growth carrying capacity population size logistic growth

logistic growth

The _____ biome is the largest of Earth's biomes. rain forest marine grassland desert freshwater

marine

For species with a Type III curve, most individuals reach the maximum life span. Supported Not supported Cannot be determined from this graph

not supported

Based on a comparison of the age-structure pyramids, which of the following would likely be a higher priority in Canada than in Niger? providing childhood vaccinations providing long-term care for the elderly building new schools providing prenatal care

providing long-term care for the elderly

What does the right y-axis represent? resources, with quantity decreasing from bottom to top time, with duration increasing from left to right resources, with quantity increasing from bottom to top population, with size increasing from bottom to top

resources, with quantity decreasing from bottom to top

The benthic zone of aquatic environments is defined as the _____. region that receives abundant sunlight region where phytoplankton are found region that receives little or no light substrate at the bottom of the body of water region that is flooded at high tide and not covered by water at low tide

substrate at the bottom of the body of water

In species that exhibit a Type II survivorship curve, individuals are no more likely to die at one stage of the life cycle than another. Supported Not supported Cannot be determined from this graph

supported

What are the two major factors determining the distribution of terrestrial biomes? temperature and light temperature and rainfall light and rainfall plants and animals temperature and plants

temperature and rainfall

Look at the age-structure pyramids. The numbers between the bars (in the middle of the graphs) serve as the y-axis. What do these numbers represent? the number of people born in a particular year the total population, in millions the percentage of the population in each age class the population of males and females the age classes, in 5-year ranges

the age classes, in 5-year ranges

What do the bars on the graphs represent? the number of males and females in each age group birth rate or death rate for each age group the percentage of males and females in each age group the number of males and females born in different years

the number of males and females in each age group

Which of these is characteristic of the photic zone of a freshwater biome? the presence of algae relatively cool water relatively stable water temperature dead organic matter low oxygen level

the presence of algae

Biomes are major life zones characterized by vegetation and climate, primarily average temperature and precipitation. Sort each characteristic to align with the appropriate biome.

tropical forest -Located along or near the equator -Large variation in annual precipitation but with high annual temperatures -Greatest human impact is rapid population growth leading to habitat destruction Temperate broadleaf forest -Located at midlatitudes, mostly in the northern hemisphere -Significant precipitation throughout the four seasons -Greatest human impact is logging and land clearing for agriculture and urban development Northern coniferous forest -Located at high latitudes in the northern hemisphere -Relatively low annual temperatures -Greatest human impact is destruction of forests through logging

Which biome is characterized by an extensive canopy that allows little light to penetrate to the ground and by the presence of epiphytes? temperate grassland coniferous forest tropical rain forest desert tundra

tropical rain forest

Which biome is characterized by the presence of permafrost? taiga tropical forest tundra coniferous forest desert

tundra

The 2010 age-structure pyramid for Niger indicates that the population of Niger ________. was increasing was stable was decreasing cannot be determined from the graph

was increasing

What data should the researchers collect and graph, and what result would support their hypothesis? Drag the labels to the targets of Group 1 in the graph below to indicate what data researchers should plot on the x- and y- axes. Then select the graph line that would support their hypothesis.

y axis: clutch size x axis: female plumage ornamentation graph: linear positive