Module 8 Populations and Communities

Question 1

Density can have effects on interactions within a population such as competition for food and the ability of individuals to find a mate.

Answer 1

true

Question 2

Mark and recapture is a method used to determine population size in mobile organisms.

Answer 2

true

Question 3

Life tables were initially developed by life insurance companies to set insurance rates.

Answer 3

true

Question 4

Death rate is the number of deaths within a population at a specific point in time.

Answer 4

true

Question 5

Population rate is the number of births within a population at a specific point in time.

Answer 5

false

Question 6

The population size of a species capable of being supported by the environment is called its ________.

Answer 6

carrying capacity

Question 7

Competitive exclusion principle states that two species cannot occupy the same niche in a habitat.

Answer 7

true

Question 8

A symbiotic relationship where both of the coexisting species benefit from the interaction is called ________.

Answer 8

mutualism

Question 9

___________________ may physically modify the environment to produce and maintain habitats that benefit the other organisms that use them.

Answer 9

foundation species

Question 10

The one-child policy was a policy in China that limited population growth by allowing urban couples to have only one child or face a fine.

Answer 10

true

Question 11

All countries have attempted to reduce the human impact on climate change by increasing their emission of greenhouse gases.

Answer 11

false

Question 12

Fossil fuels are responsible for dramatically increasing the resources available for human population growth through agriculture (mechanization, pesticides, and fertilizers) and harvesting wild populations.

Answer 12

true

Question 13

What is true about the organisms found in the yellow region of the cladogram below?

Answer 13

they evolved from a shared ancestor

Question 14

Using the phylogenetic tree below, choose the species that is most closely related to the gray wolf.

Answer 14

dog

Question 15

Based on the phylogenetic tree below, what can you conclude about jackals?

Answer 15

The golden jackal does not share the most recent common ancestor with the black-backed jackal.

Question 16

Based on the phylogenetic tree below, what can you conclude about the use of common names here instead of scientific names?

Answer 16

Common names are not an accurate depiction of phylogenetic relationships.

Question 17

Which is an accurate way to rewrite the following statement so that it reflects the process of natural selection?

“Horses decided to grow longer legs so they could outrun predators.”

Answer 17

Horses with longer legs were able to outrun predators and, therefore, had higher fitness.

Question 18

Albinism is a mutation that occurs in a wide range of species and results in organisms with a lack of pigment, so they appear completely white. For which population would you predict an increase in the number of animals with albinism?

Answer 18

a population of arctic foxes that feed on rabbits in the snow

Question 19

Birds with long, narrow beaks are able to reach insects burrowed in trees but they cannot crush seeds. Birds with short, strong beaks are able to crush seeds but they cannot reach insects. All birds are able to eat plants. If all of these birds are placed on an island with abundant seeds, insects, and plants, what would happen?

Answer 19

Specialization will likely not occur.

Question 20

Birds with long, narrow beaks are able to reach insects burrowed in trees but they cannot crush seeds. Birds with short, strong beaks are able to crush seeds but they cannot reach insects. All birds are able to eat plants. If these birds are placed on an island with a large amount of insects and a few plants, but no seeds, what would happen?

Answer 20

Over time, there would be an increase in the number of birds with longer beaks.

Question 21

Birds with long, narrow beaks are able to reach insects burrowed in trees but they cannot crush seeds. Birds with short, strong beaks are able to crush seeds but they cannot reach insects. You arrive on a new island and find that all of the birds have strong, short beaks. What should you expect the food supply to be on this island?

Answer 21

mostly seeds with some plants and a few insects

Question 22

A flood has occurred and caused a river to move slightly. The river is now separating a population of field mice, as they cannot swim across. Over time, the mice undergo a speciation event. What type of speciation occurred?

Answer 22

allopatric

Question 23

You are interested in causing a speciation event so that you can see how the process works. Which type of speciation should you choose in order to have the process occur the fastest?

Answer 23

allopatric

Question 24

During a severe storm, five sandpiper birds were blown to an uninhabited island. You go to study these birds and find that the frequency of genes is changing in every ensuing generation. Why does this occur?

Answer 24

The population size is very small and therefore does not meet the requirements of the Hardy-Weinberg equilibrium.

Question 25

In a population of sandpiper birds in California, there are two alleles for feather color. The darker allele is found in about 70% of the population. A severe storm moved in, and five sandpipers were blown to an uninhabited island. Over time, they reproduce and form a new population of 250 birds. You go to study these birds and find that in the new population, the darker feather allele is found in only 10% of the population. What is the most likely cause?

Answer 25

genetic drift following a bottleneck event

Question 26

A species of turtle contains a gene for the presence of spots on the shell, which is the dominant trait. The allele ‘A’ denotes a spotted shell, while ‘a’ denotes a uniform shell. At Hardy-Weinberg Equilibrium, how many turtles have a spotted shell if the frequency of ‘A’ is 0.8?

Answer 26

0.96

Question 27

__________ will lead to a change in the allelic frequency of a population.

Answer 27

a mutation

Question 28

Antibiotic resistance occurs when a bacterium is not killed by a specific antibiotic. This usually happens when the bacterium has a plasmid containing a gene for resistance to that antibiotic. Over time, antibiotic resistance has become a significant problem, with many populations of bacteria now resistant to specific antibiotics. By overprescribing antibiotics, humans have increased the rate of what process in bacteria?

Answer 28

natural selection

Question 29

In a volcanic lake in Nicaragua, there are two species of a small fish called cichlids. Although they are very similar in size, they are slightly different in color and they do not interbreed. Researchers know they are closely related and share a common ancestor. They hypothesize that the fish have speciated recently. Which process of speciation would have caused this?

Answer 29

sympatric

Question 30

The process of natural selection is often also called “survival of the fittest.” Based on the principles underlying natural selection, which of these would have the highest fitness?

Answer 30

a woman with six kids

Question 31

Sickle-cell anemia is a disease that causes a change in the shape of red blood cells and causes them to be less effective at carrying oxygen. However, individuals with sickle-cell anemia are resistant to malaria, a parasitic disease carried by mosquitoes that causes severe illness and even death. A global survey of human populations finds higher rates of sickle-cell anemia in countries where the malaria-carrying mosquito is more common. What has caused this increase in sickle-cell anemia in these areas?

Answer 31

natural selection

Question 32

When analyzing the phylogenetic trees of vertebrates, it is clear that lizards and snakes are older and more ancestral than birds. Based on what you know about how phylogenetic trees work, which came first: the chicken or the egg?

Answer 32

the egg

Question 33

Which of the following is best at showing the life expectancy of an individual within a population?

Answer 33

life table

Question 34

Human populations have which type of survivorship curve?

Answer 34

type I

Question 35

The statistical study of populations is called _____________.

Answer 35

demography

Question 36

The number of individuals in a population is the...

Answer 36

population size

Question 37

A ___________________ is the distribution of individuals within a habitat at a particular point in time.

Answer 37

species distribution pattern

Question 38

Species with limited resources usually exhibit a(n) ________ growth curve.

Answer 38

logistic

Question 39

The maximum growth rate characteristic of a species is called its ________.

Answer 39

biotic potential

Question 40

Species that have many offspring at one time are usually...

Answer 40

r-selected

Question 41

A forest fire is an example of ________ regulation.

Answer 41

density-independent

Question 42

An accelerating growth pattern seen in populations where resources are not limiting is known as...

Answer 42

exponential growth

Question 43

A species whose presence is key to maintaining biodiversity in an ecosystem and to disproportionately upholding an ecological community’s structure is called a ________.

Answer 43

keystone species

Question 44

When an invasive species alters the community structure it is introduced to, what can the consequence be?

Answer 44

extinction of economically important species reduced predation on some native species increased predation on some native species

Question 45

A symbiotic relationship where an organism feeds off another without immediately killing the organism it is feeding on is called...

Answer 45

parasitism

Question 46

An adaptation in which an organism looks like another organism that is dangerous, toxic, or distasteful to its predators is known as...

Answer 46

mimicry

Question 47

What is the term used to describe the number of species living in a habitat or other unit?

Answer 47

species richness

Question 48

A country with zero population growth is likely to be ________.

Answer 48

economically developed

Question 49

Which type of country has the greatest proportion of young individuals?

Answer 49

countries that are economically underdeveloped

Question 50

Which of the following is not a way that humans have increased the carrying capacity of the environment?

Answer 50

decreasing use of fossil fuels

Question 51

Long-term exponential growth carries with it the potential risks of _______.

Answer 51

famine disease large-scale death

Question 52

Human population growth exhibits ______. -

Answer 52

exponential growth

Question 53

Which of the following is not a property of Hardy-Weinberg Equilibrium?

Answer 53

a small, limited population

Question 54

When male gorillas reach sexual maturity, they leave their families. This can alter the allele frequencies of the population through which of the following?

Answer 54

gene flow

Question 55

__________ leads to evolutionary change as it is the reproduction of organisms with traits that allow them to survive environmental change.

Answer 55

natural selection

Question 56

Would genetic drift happen more quickly on an island or on the mainland?

Answer 56

island

Question 57

A species is a group of individual organisms that can…

Answer 57

interbreed. produce fertile, viable offspring.

Question 58

__________ share a similar embryonic and evolutionary origin.

Answer 58

homologous structures

Question 59

Which type of speciation involves the geographic separation of populations?

Answer 59

allopatric selection

Question 59

In sickle-cell anemia, normal homozygous individuals (SS) have normal blood cells that are easily infected with the malarial parasite. Thus, many of these individuals become very ill from the parasite, and many die. Individuals homozygous for the sickle-cell trait (ss) have red blood cells that readily collapse when deoxygenated. Although malaria cannot grow in these red blood cells, individuals often die because of the genetic defect. However, individuals with the heterozygous condition (Ss) have some sickling of red blood cells, but generally not enough to cause mortality. In addition, malaria cannot survive well within these "partially defective" red blood cells. Thus, heterozygotes tend to survive better than either of the homozygous conditions. If 9% of an African population is born with a severe form of sickle-cell anemia (ss), what percentage of the population will be more resistant to malaria because they are heterozygous (Ss) for the sickle-cell gene? (Remember p + q = 1 and p2+ 2pq + q2 = 1)

Answer 59

42%

Question 60

You have sampled a population in which you know that the percentage of the homozygous recessive genotype (aa) is 36%. Using that 36%, calculate the frequency of the "A" allele. (Remember p + q = 1 and p2+ 2pq + q2 = 1)

Answer 60

0.4

Question 61

Natural events, such as earthquakes, that kill a large portion of the population refer to the __________ and can magnify the genetic drift in a population.

Answer 61

bottleneck effect

Question 62

A __________ describes the relationships surrounding an organism, such as from which organisms it is thought to have evolved, to which species it is most closely related, and so forth.

Answer 62

phylogeny

Question 63

According to Charles Darwin, __________ is the only mechanism known for adaptive evolution.

Answer 63

natural selection

Question 64

On a phylogenetic tree, a __________ is a group of organisms that descended from a single ancestor.

Answer 64

clade

Question 65

Differences in breeding schedules can act as a form of reproductive isolation. This is called...

Answer 65

temporal isolation

Question 66

When similar traits evolve independently in species that do not share a common ancestry, this is called...

Answer 66

convergent evolution

Question 67

Scientists desire to increase the genetic variance in the cheetah population because it helps reduce the risk of __________, or the mating of genetically similar or related individuals.

Answer 67

inbreeding

Question 68

Natural selection is limited because it works at the level of the...

Answer 68

individual

Question 69

Which of the following can cause phenotypic variations in a population?

Answer 69

genetic factors environmental factors

Question 70

Which of the following is true about phylogenetic relationships and phylogenetic trees?

Answer 70

They provide information on shared ancestry and evolutionary relationships.

Question 71

Which of the following is not a way to introduce new genetic variation into a population?

Answer 71

lethal genes

Question 72

Populations in nature are constantly changing in genetic makeup due to…

Answer 72

genetic drift. random mutations. natural selection.

Question 73

Peppered moths are a great example of natural selection. Prior to the Industrial Revolution, the moths were predominantly light in color, which allowed them to blend in with the light-colored trees and lichens in their environment. But, as soot began spewing from factories, the trees became darker, the light-colored moths became easier for predatory birds to spot, and the darker moths increased in frequency because they had a higher survival rate. In recent years, factories have become cleaner, and less soot is released into the environment. What impact do you think this has had on the distribution of moth color in the population?

Answer 73

moths have shifted to a lighter color

Question 74

population genetics is the study of...

Answer 74

how selective forces change allele frequencies in a population over time.

Question 75

One of the original Amish colonies rose from a ship of colonists that came from Europe. The ship’s captain, who had polydactyly, a rare dominant trait, was one of the original colonists. Today, we see a much higher frequency of polydactyly in the Amish population. This is an example of...

Answer 75

genetic drift founder effect

Question 76

The __________ is the rate at which a specific allele appears within a population.

Answer 76

allelic frequency

Question 77

__________ refer to changes to an organism’s DNA and are important in driving diversity and evolution.

Answer 77

mutations

Question 78

Many evolutionary relationships in the modern tree have only recently been determined due to molecular evidence from…

Answer 78

nucleic analyses protein analyses

Question 79

Charles Darwin’s book, __________, outlined in considerable detail his arguments for evolution by natural selection.

Answer 79

On the Origin of Species

Question 80

__________ occurs when the probability that two individuals in a population will mate is not the same for all possible pairs of individuals in that same population.

Answer 80

non-random mating

Question 81

Which of the following involves reproductive isolation, but not geographical barriers?

Answer 81

sympatric speciation