Exam 3

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Question 1

1 / 1 pts

“Survival of the fittest” may be a misleading phrase to describe the process of evolution by natural selection, because:


Reproductive success, on its own, does not necessarily guarantee evolution



It is impossible to determine the fittest individuals in nature



Natural variation in a population is generally too great to be influenced by differential survival



Survival matters less to natural selection than does reproductive success



Question 2

1 / 1 pts

Is the following description of how giraffes evolved long necks reasonable based on the ideas of evolution by transformation?

Giraffes have long necks because they needed to reach food high in the trees. Each individual giraffe stretched to reach the highest leaves possible and developed a longer neck. Over many generations the population of giraffes had a longer and longer average neck length.








Question 3

1 / 1 pts

Prokaryotes are classified into _________ domain(s).














Question 4

1 / 1 pts

Thousands (or even tens of thousands) of different traits make up an individual. For this reason:


Knowing a person’s phenotype is insufficient for determining his or her genotype


The environment must influence more than half of our traits



All genes must be pleiotropic



In a species with 23 different chromosomes, some traits must be coded for by genes on the same chromosome



Question 5

1 / 1 pts

In a set of classic experiments performed in the early 1950s , Urey and Miller subjected an experimental system composed of H2, CH4 (methane), NH3 (ammonia), and water to electrical sparks. A few days later, they found in their system:








Amino Acids






IncorrectQuestion 6

0 / 1 pts

Which of these is most closely related according to the below figure?


  1. neanderthalisand H. habilis


  1. habilis and H. sapiens


  1. floresiensis and H. erectus


Australopithecus and H. floresiensis


Question 7

1 / 1 pts

Crossing over ______________.


Occurs during mitosis and is when genes inherited from one parent switch places with genes from another parent



Occurs during mitosis and is the main reason offspring of asexual reproduction are genetically identical



Occurs during meiosis and is the main reason offspring of asexual reproduction are genetically identical



Occurs during meiosis and is when genes inherited from one parent switch places with genes from another parent



Question 8

1 / 1 pts

Which of these is not one of the domains of life?














Question 9

1 / 1 pts

In a pedigree, a circle with a square that is shaded refers to ______________.


A female with a trait of interest



A male that does not have the trait of interest



A male with a trait of interest



A female that does not have the trait of interest



Question 10

1 / 1 pts

Which of the following scenarios would best facilitate adaptive radiation?


A population of cheetahs goes through an event in which all genetic diversity in the population is wiped out



A population of birds becomes stranded on an island archipelago



Darker colored moths have a selective advantage over lighter-colored moths due to industrial soot on trees



A population of birds native to an island archipelago is forced to relocate to the mainland by a storm



Question 11

1 / 1 pts

The mass extinction that occurred on earth 65 million years ago was immediately followed by:


The rise of the reptiles, including the dinosaurs



the emergence of the first non-photosynthetic organisms



The rapid divergence and radiation of modern mammals



The rise of archaea



IncorrectQuestion 12

0 / 1 pts

Many biologists do not consider viruses to be alive. Which of the following characteristics of viruses leads to this conclusion?


Viruses are unable to reproduce on their own



All of these



Viruses do not respond to external stimuli



Viruses lack a metabolic system



Question 13

1 / 1 pts

A woman with type B blood and a man with type A blood could have children with which of the following phenotypes?


A, B, or O only



AB or O only



AB only



A, B, AB, or O



IncorrectQuestion 14

0 / 1 pts

The biological species concept doesn’t work for ________.


Asexually reproducing organisms or fossils






Asexually reproducing organisms






Question 15

1 / 1 pts

For each cell that undergoes meiosis what is the final outcome?


Two genetically unique cells



Four genetically identical cells



Four genetically unique cells



Two genetically identical cells



Question 16

1 / 1 pts

What can be concluded from comparing differences in molecular biology among different species?


Birds are more closely related to humans than dogs are



Extremely different species are fundamentally unrelated in any way



Only DNA sequences can be used to compare species’ relatedness


Genetic similarities and differences demonstrate species relatedness



IncorrectQuestion 17

0 / 1 pts

Phylogenetic trees should be viewed as:


True genealogical relationships among species



Representation of allopatric speciation events



Intellectual exercises, not to be interpreted literally



Hypotheses regarding evolutionary relationships among groups of organisms



Question 18

1 / 1 pts

The following explanation of evolution of flight in bats doesn’t demonstrate a proper understanding of evolution by natural selection. Why not?

Bats would be better adapted if they had wings, so gradually they developed them. Bats in each generation had better wings than their parents did.


Future generations would not have better wings, on average, than their parents



Evolution happens suddenly, not gradually



Traits do not evolve because they would be useful, random mutations are needed



Natural selection only works in small populations and the bat population is large



Question 19

1 / 1 pts

When a small group of individuals colonizes a new habitat, an evolutionary event is likely to occur, because:


Gene flow increases



Small founding populations are rarely genetically representative of the initial population



New environments tend to be inhospitable, reducing survival there



Members of a small population have reduced rates of mating



IncorrectQuestion 20

0 / 1 pts

Using a light microscope , it is easiest to see chromosomes:


During asexual reproduction



During interphase, when they are concentrated in the nucleus



During mitosis and meiosis , because the condensed chromosomes are thicker and therefore more prominent



During interphase, because they are uncoiled and more linear



Question 21

1 / 1 pts

Most genes come in alternative forms called:














Question 22

1 / 1 pts

All of the offspring of a black hen and a white rooster are gray. The simplest explanation for this pattern of inheritance is:


Sex linkage



Incomplete heterozygosity



Multiple alleles



Incomplete dominance



Question 23

1 / 1 pts

What biological sex will an individual with an XXXY karyotype be?














Question 24

1 / 1 pts

In a plant species, purple flowers are dominant to white. What will the phenotypes be in the offspring of the following cross: PP x Pp?


3/4 purple, 1/4 white flowers



All Pp



All purple flowers



All light purple flowers



Question 25

1 / 1 pts

If you are crossing two peas – Rr x rr – where R is a round pea and r is a wrinkled pea:

What fraction of the offspring will be round? Is “round” the genotype or the phenotype?


0 genotype



All phenotype



1/2 phenotype



All genotype



Question 26

1 / 1 pts

The following explanation of the evolution of flight in bats doesn’t demonstrate a proper understanding of natural selection – why not?

The rodent-like ancestors of bats kept stretching their skin and arms while jumping from tree branch to tree branch because that would help them glide better and jump farther. Gradually, through the continued use of their arms in this way, they developed wings.


It would be impossible for bats to evolve from rodent-like ancestors



Stretching their arms will not cause a genetic change, so this trait can not be passed on to offspring



Gliding and flying are different and one could not lead to the other



Question 27

1 / 1 pts

Which of the following is true?


Both genetic drift and gene flow require population size to be small in order to impact the allele frequencies



With the founder effect individuals are leaving one population to begin a new population elsewhere



With the founder effect, individuals are moving from one existing population to another



IncorrectQuestion 28

0 / 1 pts

In the figure below what is the most recent common ancestor between H. neanderthalensis and H. sapiens?




  1. heidelbergensis


  1. neanderthalensis


  1. floresiensis


Question 29

1 / 1 pts

Asexual Reproduction __________________


Involves two parents and produces offspring that are genetically identical



Involves one parent and produces offspring that are genetically unique



Involves one parent and produces offspring that are genetically identical



Involves two parents and produces offspring that are genetically unique



Question 30

1 / 1 pts

Pea plants were well suited for Mendel’s breeding experiments for all of the following reasons except:


Pea plants exhibit variations in an umber of observable characteristics, such as flower color and seed shape.



Pea plants have a particularly long generation time



Mendel could control the pollination between different pea plants



It is easy to obtain large numbers of offspring from any given cross



Question 31

1 / 1 pts

Selecting for increased starvation resistance in fruit flies:


Has little effect, because ongoing mutation counteracts any benefits from selection



Cannot increase their survival time, because there is no genetic variation for this trait



Has no effect, because starvation resistance is not a trait that influences fruit flies’ fitness


Can produce populations in which the average time to death from starvation is 160 hours



Question 32

1 / 1 pts

A karyotype of one of your skin cells would reveal a total of 46 chromosomes. How many of these are maternally inherited non-sex chromosomes?














Question 33

1 / 1 pts



Is responsible for the increased occurrence of antibiotic-resistant bacteria



Does not occur in human-occupied habitats



Can occur in the wild but not in the laboratory



Occurs too slowly to be observed



Question 34

1 / 1 pts

In animals, it is believed that the most common mode of speciation is:














Question 35

1 / 1 pts

The idea of punctuated equilibrium challenges which component of Darwin’s theory of evolution?


Steady change and species stasis



Species stasis and gradualism



Steady change and gradualism



None of these



IncorrectQuestion 36

0 / 1 pts

Adaptations shaped by natural selection:


May be out of date, having been shaped in the past under conditions that different from those in the present



Are magnified and enhanced through genetic drift



Represents perfect solutions to the problems posed by nature



Are unlikely to be present in humans living in industrial societies



IncorrectQuestion 37

0 / 1 pts

What happens to a zygote with the wrong number of autosomes?


None of these



It will develop into a male



It will develop into a female



It will likely experience a spontaneous miscarriage



IncorrectQuestion 38

0 / 1 pts

Most archaeal species:


are animal parasites



are beneficial to humans



are pathogenic



have yet to be discovered



Question 39

1 / 1 pts

What kind of molecule is thought to be the most likely to have been the first genetic material?














Question 40

1 / 1 pts

Which of the following groups would be placed nearest the fungi in an evolutionary tree based on DNA sequences?














Question 41

1 / 1 pts

Two flowers look very similar, but generally reproduce at different times during the year. One breeds in the summer and the other in the spring. Are these flowers different species?








Question 42

1 / 1 pts

Which of the following is the process for sex determination in turtles?


Sex is determined by whether the egg carries a W or Z chromosome



Sex is determined by whether the sperm carries an X or Y chromosome



Sex is determined by the number of chromosome sets an individual possesses



Sex is determined by the temperature at which the eggs are incubated



Question 43

1 / 1 pts

Sister chromatids are:


Homologous chromosomes



The result of crossing over



Identical molecules of DNA resulting from replication



Produced in meiosis but not in mitosis



Question 44

1 / 1 pts

The genetic information in all viruses is:














Question 45

1 / 1 pts

No karyotype has ever shown a person to have one Y chromosome and no X chromosome. Why?


The X chromosome contains genes that are essential for life.



Individuals are probably born with this karyotype, but have such slight phenotypic abnormalities that they live out their lives normally and are unaware of this genetic anomaly



Genes on the Y chromosome are expressed only when an X chromosome is present



A karyotype would not reveal such an abnormality



Question 46

1 / 1 pts

Which of the following refers to the unicellular stage of development














Question 47

1 / 1 pts

Does the following explanation of the evolution of flight in bats demonstrate a proper understanding of natural selection?

Bats would be better adapted if they had wings, so gradually they developed them. Bats in each generation had better wings than their parents did.








Question 48

1 / 1 pts

Which of the following statements about antibiotics is incorrect?


Penicillin was the first antibiotics widely used to fight bacterial infections



Antibiotics help microbes compete with other microbes



Antibiotics are used not just in human health care but also in agriculture



Antibiotics, though effective against viruses, are not effective against bacteria



IncorrectQuestion 49

0 / 1 pts

In a fish population in a shallow stream, the genotypic frequencies of yellowish-brown fish and greenish-brown fish changed significantly after a flash flood randomly swept away fish from the stream. This change in genotypic frequency was most likely attributable to:


Disruptive Selection



Directional Selection



Gene Flow



Genetic Drift



Question 50

1 / 1 pts

Which of the following statements about mutations is incorrect?


Most mutations are harmful or neutral for the organism in which they occur



All of these statements are correct



A mutation is any change in an organism’s DNA


The origin of genetic variation is mutation


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