Principles of Ecology-Week 16

Question 1

You construct a life table for a plant species and find that in all cases about the same proportion of the cohort survive to the beginning of the next time interval. What would you call this?

a Type II survivorship curve
a semelparous life history adaptation
a Type III survivorship curve
a Type I survivorship curve

Answer 1

a Type II survivorship curve

Question 2

A small group of mice were released on an island. The island previously had no mice on it, but had abundant food and no predators. After several years of growth, the size of the new island population stabilizes. However, at this point a hurricane drastically reduces the population. How would you describe the situation?

The biotic potential of the population has been reduced.
The island mouse population can now act as a sink metapopulation.

The new population size is a result of density-independent regulation.

The new population size is a result of density-dependent regulation.

Answer 2

The new population size is a result of density-independent regulation.

Question 3

Which of the following is an example of a species with r-selected adaptations?

house fly
blue whale
horse
gorilla

Answer 3

house fly

Question 4

What are population pyramids used to show?

the carrying capacity
death rates
birth rates
age composition of a population

Answer 4

age composition of a population

Question 5

The size at which a population stabilizes in a particular place is defined as the __________ for that species.

range
carrying capacity
growth potential
optimum

Answer 5

carrying capacity

Question 6

Which is an example of a clumped distribution of a population?

Two male hummingbirds have a confrontation on the border between their territories.

Antelope travel in herds.
A tree species releases a poison to defend the soil around its roots, resulting in trees spaced evenly like a grid.

Multiple species join each other at the waterhole to drink.

Answer 6

Antelope travel in herds.

Question 7

What is the life history adaptation called where organisms produce offspring several times over many seasons?

semelparity
iteroparity
polyparity
alloparity

Answer 7

iteroparity

Question 8

Kettle ponds derive from a hole left by a retreating glacier that is subsequently filled with rainwater. A certain region has a series of disconnected kettle ponds, but occasionally heavy rains flood them and create streams. Which type of animal is most likely to be present in this area as a metapopulation?

a dragonfly
an aquatic bird

a fish
a mosquito

Answer 8

a fish

Question 9

Under which condition will a population experience growth?

when dN/dt equals zero
when N is less than K
when N equals K
when r equals zero

Answer 9

when N is less than K

Question 10

An important sporting event took place in Denver, Colorado (elevation: 5280 ft). Both teams were visiting the city for the event. Team A arrived a week in advance, but Team B arrived just one day before the game. What may have been a factor that contributed to Team B’s poor performance?

Team B acclimated to the high altitude, whereas Team A maintained physiological adjustment to their home town.
Team B did not have enough time for their DNA to evolve in response to the high altitude.
Team B was from a country that did not give them experience with low altitude.

Team B did not have enough time for their bodies to adjust physiologically to high altitude.

Answer 10

Team B did not have enough time for their bodies to adjust physiologically to high altitude.

Question 11

The statistical study of populations including sex ratio, age structure, and predicting growth rates is called _________.

demography
biometrics
ethology
population genetics

Answer 11

demography

Question 12

Select the description of a population pyramid for a population that has the largest potential for exponential growth.

broad at the top, narrow at the base, with more males than females
uniform at all age classes, with more females than males

broad at the base, narrow at the top, with more females than males
broad at the base, narrow at the top, with more males than females

Answer 12

broad at the base, narrow at the top, with more females than males

Question 13

Within a genus that normally produces large numbers of offspring, one particular species evolves maternal care behavior. What do you predict will happen to the survivorship curve?

It may change from type I to type II.
No change is likely.

It may change from type III to type I.
It may change from type I to type III.

Answer 13

It may change from type III to type I.

Question 14

Many times species are composed of networks of distinct populations called metapopulations. When do metapopulations occur?

When a population in a better habitat does not send out colonizers into less suitable habitats.
When a population is large and uniformly distributed.
When a population in poor habitat continually sends out dispersers to bolster populations in better habitats.

When suitable habitat is patchily distributed and separated by areas of unsuitable habitat.

Answer 14

When suitable habitat is patchily distributed and separated by areas of unsuitable habitat.

Question 15

A rancher is suspected of shooting wolves near Yellowstone National Park, and you have been enlisted to go have a chat with him. The rancher doesn’t see any benefit to having the wolves there. What do you say?

“If there are no predators like wolves, just one pair of jackrabbits can quickly create a population with explosive, logistic growth. Wolves help reduce the fecundity rate, keeping the population at a reasonable level.”
“If there are no predators like wolves, just one pair of jackrabbits can quickly create a metapopulation. Wolves help reduce the biotic potential, keeping the population at a reasonable level.”
“If there are no predators like wolves, just one pair of jackrabbits can quickly create a population with explosive, density-dependent growth. Wolves help reduce the age structure, keeping the population at a reasonable level.”

“If there are no predators like wolves, just one pair of jackrabbits can quickly create a population with explosive, exponential growth. Wolves help reduce the carrying capacity, keeping the population at a reasonable level.”

Answer 15

“If there are no predators like wolves, just one pair of jackrabbits can quickly create a population with explosive, exponential growth. Wolves help reduce the carrying capacity, keeping the population at a reasonable level.”

Question 16

What do we call populations of organisms that are usually near the carrying capacity?

r-selected
parasites
K-selected
predators

Answer 16

K-selected

Question 17

In the sigmoid growth curve, the carrying capacity of the environment is indicated by what symbol?

N/K
ri

K
dN/dt

Answer 17

K

Question 18

You are earning your Ph.D. in marine biology, studying the microbial ocean community. This year, you are shocked to discover that one of your study sites has become contaminated due to an industrial waste water pipe. This dumping is drastically raising the temperature and lowering the salinity of the water. What do you expect to find in your survey of the ecosystem, and what might you find in a survey years from now?

The individuals will turn on genes to adapt to these changes, and the populations will end up largely the same this year and following years.
Most species will be wiped out this year, and it will take millions of years for new species to evolve – until then the site will be devoid of life.

Many species will have decreased or disappeared from this site, but later some species may increase in population if they acquire adaptive mutations. Also you may see some new species expand into the site.
Most species will be wiped out this year, and in subsequent years even fewer will remain.

Answer 18

Many species will have decreased or disappeared from this site, but later some species may increase in population if they acquire adaptive mutations. Also you may see some new species expand into the site.

Question 19

A group of population members all of the same age is called a ________.

tribe

cohort
deme
species

Answer 19

cohort

Question 20

Effects that are dependent on the size of the population and regulate the growth of populations are called ___________ effects.

density-independent
K-related
demographic

density-dependent

Answer 20

density-dependent

Question 21

You and your friends have just stepped off the plane in Cusco, Peru (11,200 ft). Your friends are so eager to see Machu Picchu they want to start off hiking the Inca Trail right away and not waste any time. How do you respond?

“Sounds good, but we had better bring our warmest clothes.”
“No problem – we had the whole plane ride to acclimatize to the high altitude.”

“Waiting a few days might be smart, since it takes time to acclimate to high altitude.”
“Sounds good, but we had better pack extra water.”
“Sounds good, but we had better pack extra water.”

Answer 21

“Waiting a few days might be smart, since it takes time to acclimate to high altitude.”

Question 22

Parental care of the young is usually associated with species with a type ___ survivorship curve.

I or II (depending on the sex ratio)

I
II
III

Answer 22

I

Question 23

Which factor increases the likelihood of population extinction?

isolation of a population from density-independent effects
high genetic diversity

isolation of a population from sources of immigrants
large population size

Answer 23

isolation of a population from sources of immigrants

Question 24

Which is an example of a species with K-selected adaptations?

bobcat
herring
dandelion
fruit fly

Answer 24

bobcat

Question 25

During the late 1800s, cattle egrets arrived in South America from Africa and began to colonize. Their range has expanded dramatically over the years. Why were they able to do this?

The habitats that they encountered in South America were suitable to them and unoccupied.

There were abundant cattle for the birds to gather around in South America; furthermore, various animals that the egrets had lived around in Africa had become quite scarce because of over hunting and poaching, causing the birds to extend their range.

The habitats that they left in Africa were not suitable for any further colonization; thus, they were forced to emigrate.

The food resources in South America were far superior to those in Africa, allowing the egrets more opportunity to grow and reproduce and ultimately expand their range.

Answer 25

The habitats that they encountered in South America were suitable to them and unoccupied.

Question 26

The trade-off between investments in current reproduction and in growth that promotes future reproduction is referred to as the total cost of what?

adaptation
reproduction
genetic change
fitness

Answer 26

reproduction

Question 27

Which is an example of a density-independent factor on a population?

weather
predation
amount of prey
intraspecific competition

Answer 27

weather

Question 28

Organisms such as lizards that need to maintain body temperature through external means do so by

shivering to produce heat.
swimming in geothermal pools.
sunbathing.
running frequently to warm up.

Answer 28

sunbathing

Question 29

What would happen to the COVID-19 case counts if the R0R0
value of the SARS-CoV-2 increases?

They would decrease.
They would be kept constant.
They would increase.
They would not be affected.

Answer 29

They would increase.

Question 30

Which is an example of a clumped distribution of a population?

A tree species releases a poison to defend the soil around its roots, resulting in trees spaced evenly like a grid.
Multiple species join each other at the waterhole to drink.
Two male hummingbirds have a confrontation on the border between their territories.
Antelope travel in herds.

Answer 30

Antelope travel in herds.

Question 31

The figure included shows the body temperature of lizards versus air temperature in two different habitats—open and shaded forest. Which one of the following conclusions is best supported by these data.

Lizards sunbathe more in open habitats.
Lizards in shaded forest habitats eat more to maintain their temperature.
The body temperature of lizards is more constant in open than in shaded forest habitats.
Lizards are more active in open habitats.

Answer 31

The body temperature of lizards is more constant in open than in shaded forest habitats.

Question 32

A farmer’s land includes a wilderness area that is home to an endangered species of bird. He wants to sell the land to a developer, and you have been hired to evaluate the environmental concerns. “This little patch of land is not crucial for the bird species!” the farmer says, “In fact, my land is surrounded by several other wilderness patches that also have that bird.” You reply: “It is possible that your land acts as the ____________ and the other areas are ___________ . If that’s the case, development would be devastating to the population.”

population; metapopulation
metapopulation; population
source; sinks
sink; sources

Answer 32

source; sinks

Question 33

What kind of population spacing would you expect for a species that is strongly territorial?

random
uniform
clumped
uniform or clumped depending on whether it is a source or sink metapopulation

Answer 33

uniform

Question 34

The rate at which a population of a given species will increase when no limits are placed on its rate of growth is called its

maximum growth.
carrying capacity.
biotic potential.
optimal growth.

Answer 34

biotic potential

Question 35

Which factor allows bacteria species to adapt to environmental changes faster than fish?

lack of a nuclear membrane
lack of a nuclear membrane
smaller nutrient needs
shorter generation time

Answer 35

shorter generation time

Question 36

Populations of endotherms that live in colder climates tend to have shorter ears and limbs than populations of the same species in warm climates. This is called ____________ Rule.

the r-Selected
the K-Selected
Allen’s
Edward’s

Answer 36

Allen’s

Question 37

Which organism is most likely to have a type III survivorship curve?

a domestic dog
Paramecium
an oak tree
corn in a farmer’s field

Answer 37

an oak tree

Question 38

In the sigmoid growth curve, the number of individuals at any one time is indicated by what symbol?

N/K
ri
N
K

Answer 38

N

Question 39

What is the Allee effect?

when growth rates increase independently of population size
when fitness and growth rates increase with decreasing population size
when fitness and growth rates increase with increasing population size
when fitness increases independently of population size

Answer 39

when fitness and growth rates increase with increasing population size

Question 40

You and your friend are on vacation at Yellowstone Park. The plaque in front of a sulfur hot spring reads: “This sulfur spring is 80°C, has a pH of 2, and contains large amounts of sulfur which is oxidized by Sulfolobus species of archaea.” Your friend is excited. “Boy, if those microbes are that tough they should be easy to grow in the lab. I think I’ll work with those for my summer project.” What do you think?

The sulfur spring is pretty extreme, but after a few generations the species should have adapted to the lab culture conditions.

You agree, and decide to partner with your friend to work on this organism as well.

A species adapted to such extreme conditions would probably not be easy to culture in the very different conditions of a lab.

The sulfur spring is pretty extreme, but after a few days the individual archaea should have adapted to lab culture conditions.

Answer 40

A species adapted to such extreme conditions would probably not be easy to culture in the very different conditions of a lab.

Question 41

Would you expect that mated female fruit flies would live longer or shorter than unmated fruit flies, and why?

Mated flies live longer, because they use less energy traveling about looking for a mate.

Mated flies live shorter, because they use more energy producing eggs.

Mated flies live the same amount of time, because none of these factors is very significant.

Mated flies live shorter, because they use more energy in the act of mating.

Answer 41

Mated flies live shorter, because they use more energy producing eggs.

Question 42

A species colonizes an island, goes through a phase of exponential growth, and reaches the carrying capacity of the island. At what stage is the growth rate slowest?

approaching K
initial colonization
after reaching K
exponential phase

Answer 42

after reaching K

Question 43

This summer, you are returning to the research station in Costa Rica to follow up on the population of butterflies you have been studying. You are disappointed to find that there are fewer this year than last. In fact, at dinner your friends studying frogs and birds are complaining about the same thing. What type of influence do you suspect?

a density-independent effect like environmental disruption
a density-independent effect like an introduced predator
a density-dependent effect like an introduced predator
a density-dependent effect like environmental disruption

Answer 43

a density-independent effect like environmental disruption

Question 44

In the logistic growth model, as the number of individuals in the population (N) approaches the carrying capacity (K), what happens to the intrinsic rate of growth (ri)?

It will not change.
It will be affected by an increased birth rate.
It will be affected by increased competition with other species.
It will be affected by increased competition within the species.

Answer 44

It will not change

Question 45

What is the most reasonable conclusion that can be made from data graphed in the figure?

After low mortality early in life, mortality increases to a constant rate for the rest of life.

After following a constant rate early in life, mortality becomes low late in life.

Survivorship is constant throughout life.

After following a constant rate early in life, mortality becomes low late in life.

Answer 45

After low mortality early in life, mortality increases to a constant rate for the rest of life.

Question 46

The range of a population

Group of answer choices

changes over time due to external events.

is stable and almost never changes.

only changes after a disaster has wiped out a former range.

is very fluid and changes frequently in a random fashion.

Answer 46

changes over time due to external events.

Question 47

The biotic potential representing growth without limits at its maximal rate is indicated by what symbol?

dN/dt

N

K

ri

Answer 47

ri

Question 48

A small group of mice are released on an island without mice but with abundant food for mice and no predators. Initially, the growth of the mouse population will be limited mainly by what?

only density-independent factors

the biotic potential

only density-dependent factors

the carrying capacity

Answer 48

the biotic potential