Bio 102 Unit Test 1

Question 1

Darwin originally defined evolution as

Answer 1

descent with modification

Question 2

Observation that must be explained in a unifying theory
about life?

Answer 2

Many basic characteristics are shared by all living things.

Question 3

True statement about Charles Darwin

Answer 3

He proposed natural selection as the mechanism of evolution.

Question 4

During his voyage around the world, Darwin was inspired to think about evolution by

Answer 4

a. the unique organisms he saw in the Galápagos Islands

b. fossils he collected

c. studying adaptations of organisms to their environments

d. the works of others such as Lamarck

Question 5

In Darwin’s view of descent with modification,

Answer 5

natural selection can improve the match between an organism and its
environment

Question 6

The breeding of plants and animals for particular traits by humans is called

Answer 6

artificial selection

Question 7

The smallest unit that can evolve is a

Answer 7

Population

Question 8

Which of the following is an example of the process of evolution?

Answer 8

Herbivory

Question 9

According to the theory of evolution, anatomical and molecular homologies should

Answer 9

produce similar patterns of evolutionary relatedness

Question 10

How did some strains of Staphylococcus aureus become resistant to antibiotic drugs

Answer 10

Some members of the bacteria population must have had genetic variation
that made them resistant to antibiotics, and these bacteria had greater
reproductive success than sensitive individuals.

Question 11

Seemingly dissimilar organisms such as hummingbirds, humans, and whales have similar
skeletal structures. This most directly suggested to biologists that

Answer 11

dissimilar organisms might have evolved from a distant, common ancestor

Question 12

Animals that possess homologous structures probably

Answer 12

evolved from the same ancestor

Question 13

On an evolutionary tree

Answer 13

homologous characteristics form a nested pattern
c. scientists are sure of the correct placement and relation

Question 14

Which of the following is an example of convergent evolution?

Answer 14

Dolphins and sharks have a similar streamlined body shape.

Question 15

Vestigial organs are

Answer 15

remnants of structures that were useful to an organism’s ancestors but that
are now nonfunctional or show reduced function

Question 16

All known organisms translate genetic information to produce protein molecules via the
same genetic code. This finding strongly supports the hypothesis that

Answer 16

all organisms are descended from a single common ancestor

Question 17

Evidence from molecular biology supports the theory of evolution by demonstrating that

Answer 17

closely related organisms have more similar DNA and proteins than more
distantly related organisms

Question 18

What did Darwin observe about species on islands?

Answer 18

They are often closely related to species from the nearest mainland or
neighboring islands.

Question 19

To describe evolution as a “scientific theory” means that

Answer 19

it is a broad model that is supported by many observations and much
experimental evidence

Question 20

How do we define evolution?

Answer 20

change in a population’s allele frequencies over generations.

Question 21

Allele frequencies can be altered b

Answer 21

a. genetic drift

b. gene flow

c. natural selection

Question 22

Which of the following mechanisms can form entirely new alleles?

Answer 22

Mutation

Question 23

Sexual recombination includes the shuffling of chromosomes in
____ and fertilization.

Answer 23

meiosis

Question 24

Which type of mutation plays the most important role in increasing the number of genes
in the gene pool?

Answer 24

Duplication

Question 25

Which of the following would seem to be an example of neutral variation?

Answer 25

Human fingerprints

Question 26

What is the importance of neutral variation in evolution?

Answer 26

Neutral variation increases genetic variation, allowing a population to carry more alleles that may help it respond to environmental change.

Question 27

In the Hardy-Weinberg equation, p2 represents

Answer 27

The expected frequency of homozygous dominant individuals in the population

Question 28

In the equation for Hardy-Weinberg equilibrium, 1 represents

Answer 28

the sum of the frequencies of the genotypes for a particular gene locus

Question 29

Which of the following sets of conditions is required for Hardy-Weinberg equilibrium?

Answer 29

Random mating, no natural selection, and a large population

Question 30

An earthquake hits a small island. All but a small group of closely related lizards are eliminated, and the survivors spread out over the island. This is an instance of

Answer 30

bottleneck effect

Question 31

Which of the following scenarios would most likely result in the microevolution of a population of humans?

Answer 31

A colony of humans on the moon is isolated from Earth.

Question 32

Which of the following is the best example of gene flow?

Answer 32

Wind blows pollen from one population of plants to another and cross-fertilization occurs.

Question 33

Which of the following most accurately measures an organism's fitness?

Answer 33

how many fertile offspring it produces

Question 34

Antibiotic resistance in bacteria is an example of which of the following?

Answer 34

Directional selection

Question 35

Stabilizing selection

Answer 35

favors intermediate variants in a population

Question 36

Which type of selection maintains stable frequencies of two or more phenotypic forms in a population?

Answer 36

Balancing selection

Question 37

Selection that acts over evolutionary time to preserve traits that increase an individual's ability to mate is known as

Answer 37

sexual selection

Question 38

A number of mosquito populations today are resistant to insecticides that were once quite effective. Biologists think that insecticide resistance evolved in mosquitoes because

Answer 38

a few mosquitoes were probably resistant to the insecticide before it was ever used, and these individuals were more likely to survive and reproduce in the presence of insecticide

Question 39

When gene flow between two populations ceases, the potential for __________ exists.

Answer 39

speciation

Question 40

At which point in the adaptation of a population is it clear that speciation has occurred?

Answer 40

Gene pool changes establish reproductive barriers between two populations.

Question 41

Prezygotic barriers

Answer 41

prevent fertilization of gametes from members of closely related species

Question 42

Which reproductive barrier actually prevents individuals of closely related species from copulating successfully?

Answer 42

Mechanical isolation

Question 43

an example of a postzygotic reproductive barrier?

Answer 43

Two fruit flies of different species produce sterile offspring.

Question 44

Which of the following conditions is necessary for speciation to occur?

Answer 44

Reproductive isolation

Question 45

evolutionary mechanisms does not contribute to the process of allopatric speciation?

Answer 45

Gene flow

Question 46

A new species can arise in a single generation

Answer 46

if a change in chromosome number creates a reproductive barrier

Question 47

In a hybrid zone, which of the following would tend to lead to reinforcement?

Answer 47

a. Reduced hybrid viability b. Hybrid breakdown c. Sexual selection d. Reduced hybrid fertility

Question 48

In the case of the Lake Victoria cichlids, sympatric speciation has been shown to be driven by

Answer 48

sexual selection

Question 49

How many genes must change in order to form a new species?

Answer 49

There is no set number of genes or loci that produces a new species. Genetic and environmental factors interact.

Question 50

The time interval between speciation events is typically

Answer 50

Times between speciation events vary widely and depend on generation times, causes of speciation, environmental factors, and chance.

Question 51

The early atmosphere on Earth is thought to have lacked which of the following gases?

Answer 51

Oxygen

Question 52

Currently scientists think the early atmosphere probably consisted of

Answer 52

N2, H2O, CO2, NH3, CH4, and H2

Question 53

The Miller and Urey abiotic synthesis experiment (and subsequent, similar experiments) showed that

Answer 53

simple organic molecules can form spontaneously under conditions like those thought to prevail early in Earth's history

Question 54

Abiotically produced vesicles display which of the following rudimentary qualities necessary for life?

Answer 54

The ability to perform simple reproduction and metabolism

Question 55

Many researchers now believe that the first self-replicating molecules were

Answer 55

RNA

Question 56

Single-celled prokaryotes had Earth to themselves for approximately

Answer 56

1.5 billion years

Question 57

The correct order of the geologic eras, from most ancient to most recent, is

Answer 57

Paleozoic, Mesozoic, Cenozoic

Question 58

Ancient cyanobacteria were very important in the history of life because they

Answer 58

produced atmospheric oxygen

Question 59

What prokaryotic adaptation occurred during the oxygen revolution and opened up the possibility for energy-demanding multicellular life-forms?

Answer 59

Cellular respiration

Question 60

What evidence supports the hypothesis that mitochondria and plastids evolved from prokaryotic endosymbionts?

Answer 60

The first and third responses are correct.