Origins of Specie & Macroevolution-Week 15

Question 1

Scientists found that different beak shapes correlate with different mating songs in Darwin’s finches. Which hypothesis is most likely to explain this?

Adaptation to different food sources likely occurred after reproductive isolation in Darwin’s finches.
Adaptation to different food sources led to behavioral isolation in Darwin’s finches.
Mating songs are primarily determined by the acoustics of different beaks.
Darwin’s finches are not different species according to the Biological Species Concept.

Answer 1

Adaptation to different food sources led to behavioral isolation in Darwin’s finches.

Question 2

Many male songbirds have very distinctive songs that are used to attract females. These songs are an example of a _________isolating mechanism.

postzygotic, ecological
postzygotic, mechanical
prezygotic, behavioral
prezygotic, temporal

Answer 2

prezygotic, behavioral

Question 3

Males of many marsupial species have forked penises that are incompatible with the anatomy of female placental mammals. What type of isolating mechanism does this represent?

temporal isolation
mechanical incompatibility
ecological isolation
hybrid sterility

Answer 3

mechanical incompatibility

Question 4

Which isolating mechanism is postzygotic?

mechanical isolation
behavioral isolation
ecological isolation
hybrid sterility

Answer 4

hybrid sterility

Question 5

In the southeastern U.S., two species of wild lettuce (Lactuca) do not usually form hybrids, because they bloom at different seasons. The means of isolation appears to be

prezygotic and geographical.
prezygotic and mechanical.
prezygotic and temporal.
postzygotic and behavioral.

Answer 5

prezygotic and temporal.

Question 6

If a new species is produced by the interbreeding of two members of distinct species, this would be _________ speciation achieved via _________.

sympatric; allopolyploidy
sympatric; autopolyploidy
allopatric; autopolyploidy
allopatric; allopolyploidy

Answer 6

sympatric; allopolyploidy

Question 7

Evolution acts at the level of the

population.
individual.
community.
ecosystem.

Answer 7

population

Question 8

Which statement is true about speciation on island archipelagos?

Speciation by polyploidy is most common.
Ecological competition may cause new species to go extinct slowing speciation.
Most speciation occurs allopatrically.
Species clusters are less common.

Answer 8

Most speciation occurs allopatrically.

Question 9

NASA Scientists send a small population of dogs to an earth-like exoplanet in order to test if it will be hospitable for human colonization. Through a random lottery, only Great Dane and St. Bernard dog breeds are sent, and the resulting population consists of tall, longhaired dogs. After 100 years these dogs return to Earth and are no longer able to mate with Earth dogs. This scenario is an example of

sympatric speciation through genetic drift.
allopatric speciation through natural selection.
allopatric speciation through genetic drift.
sympatric speciation through natural selection.

Answer 9

allopatric speciation through genetic drift.

Question 10

In 1938, scientists found a population of coelacanths in the Indian Ocean. This fish species is considered a “living fossil” and appears not to have changed morphologically for 80 million years. This discovery supports the _________ model of evolution.

natural selection
gradualism
punctuated equilibrium
adaptation

Answer 10

punctuated equilibrium

Question 11

Due to character displacement, two closely related species may differ most morphologically when they

occupy the same niche.
are sympatric.
share a common ancestor.
are allopatric.

Answer 11

are sympatric.

Question 12

Two populations that inhabit the same area but remain genetically distinct can best be called

sympatric species.
genera.
allopatric species.
subspecies (races).

Answer 12

sympatric species.

Question 13

Which isolating mechanism is postzygotic?

hybrid sterility
behavioral isolation
ecological isolation
mechanical isolation

Answer 13

hybrid sterility

Question 14

A type of isolating mechanism that leads to reproductive isolation after a hybrid zygote has formed is called a _________ isolating mechanism.

hybridization
postzygotic
adaptive
prezygotic

Answer 14

postzygotic

Question 15

How many mass extinctions have been identified during the history of life on Earth?

Two
Three
Five
Four

Answer 15

Five

Question 16

The model that assumes that evolution proceeds with slow successive change in a given evolutionary line is referred to as

punctuated equilibrium.
the sympatric model.
gradualism.
the allopatric model.

Answer 16

gradualism

Question 17

The sunflower species Helianthus anomalus is thought to have been formed by hybridization between the sunflower species H. petiolaris and H. annuus because it contains a set of chromsomes from both parental species. H. anomalus is most likely an example of instantaneous speciation through

allopolyploidy.
autopolyploidy.
parthenogenesis.
hybrid sterility.

Answer 17

allopolyploidy.

Question 18

The hundreds of species of Drosophila in Hawaii exhibit different mating rituals. This isolating mechanism is

postzygotic and mechanical.
prezygotic and temporal.
prezygotic and ecological.
prezygotic and behavioral.

Answer 18

prezygotic and behavioral.

Question 19

When species are kept separate by preventing the formation of hybrid zygotes, the mechanism that keeps the species separate is known as a _________ isolating mechanism.

prezygotic
adaptive
hybridization
postzygotic

Answer 19

prezygotic

Question 20

If two species are competing for the same resource, then either one species is likely to go extinct through competitive exclusion, or natural selection will drive the evolution of

hybrids.
polyploid individuals.
character displacement.
prezygotic isolating mechanisms.

Answer 20

character displacement

Question 21

If two species are competing for the same resource, then either one species is likely to go extinct through competitive exclusion, or natural selection will drive the evolution of

hybrids.
polyploid individuals.
character displacement.
prezygotic isolating mechanisms.

Answer 21

character displacement

Question 22

The type of speciation that results in the formation of separate species as a result of geographic isolation is called _________speciation.

gradual
sympatric
adaptive
allopatric

Answer 22

allopatric

Question 23

A type of isolating mechanism that leads to reproductive isolation after a hybrid zygote has formed is called a _________ isolating mechanism.

hybridization
prezygotic
adaptive
postzygotic

Answer 23

postzygotic

Question 24

Punctuated equilibrium proposed by Eldredge and Gould in 197 is an evolutionary process that involves

gradual change observable in the fossil record followed by periods of stasis.
“spurts” of change observable in the fossil record with very little if any stasis.
gradual change observable in the fossil record with very little, if any, stasis.
“spurts” of change observable in the fossil record followed by periods of stasis.

Answer 24

“spurts” of change observable in the fossil record followed by periods of stasis.

Question 25

A virgin pine forest covers a valley, and one of the inhabitants is a red squirrel species. A large volcanic eruption occurs and separates the valley with a huge lava flow, thus producing two populations of squirrels. What must occur for the two populations of squirrels to be considered separate species?

The two squirrel populations must be reproductively isolated.
The fur color or other morphological characteristic of the two squirrel populations must become distinct.
The two squirrel populations must select mates using different behaviors.
The two squirrel populations must feed on different species of plants.

Answer 25

The two squirrel populations must be reproductively isolated.

Question 26

Which is an example of temporal isolation?

two plant species live on the same mountainside, but one lives on rocky outcrops and the other in open meadows.
two plant species have incompatible gametes.
one plant species is pollinated by bees and a second plant species is pollinated by moths.
one plant species blooms in June-July and a second plant species blooms in August-September.

Answer 26

one plant species blooms in June-July and a second plant species blooms in August-September.

Question 27

Diversification of mammals after the extinction of the dinosaurs is considered an adaptive radiation because a few mammal species rapidly evolved into most of the current mammalian lineages in a relatively short amount of time. This diversification was partially driven by the evolution of endothermic homeostasis in mammals, which is an example of

hybridization.
allopatric speciation.
a key innovation.
reproductive isolation.

Answer 27

a key innovation

Question 28

Several species of sea urchins may inhabit the same tide pool and their reproductive periods overlap. Although they practice external fertilization, they seldom interbreed because eggs produce chemicals that are only attractive to sperm of their own species. This is an example of a _________barrier that _________.

postzygotic; prevents zygote fusion
prezygotic; causes geographic isolation
prezygotic; prevents gamete fusion
prezygotic; causes temporal isolation

Answer 28

prezygotic; prevents gamete fusion

Question 29

Choose the best cause and effect sequence for the process of speciation by natural selection.

Selection → Speciation → Reproductive Isolation → Variation → Mutation
Mutation → Variation → Selection → Reproductive Isolation → Speciation
Variation → Reproductive Isolation → Speciation → Mutation → Selection
Speciation → Reproductive Isolation → Selection → Mutation → Variation

Answer 29

Mutation → Variation → Selection → Reproductive Isolation → Speciation

Question 30

If populations within the same area split into species, the process is known as

ecotypical speciation.
racial speciation.
allopatric speciation.
sympatric speciation.

Answer 30

sympatric speciation

Question 31

According to the biological species concept, two groups of organisms that are unable to form fertile, viable hybrids are considered to be different

races.
kingdoms.
hybrids.
species.

Answer 31

species

Question 32

Courtship for Anolis lizards involves the male displaying a dewlap (skin under the throat area) that varies in appearance based upon the species. Lizards that are found in darker, more shaded environments will have dewlaps that are lighter in color because they are more noticeable by potential mates. Which of the following mechanisms best explains how speciation is at work in this example?

Natural selection
Reinforcement
Genetic drift
Postzygotic isolation

Answer 32

Natural Selection

Question 33

Once species have formed, they keep their identity by

genetic blocks.
developmental differences.
somatic mutations.
isolating mechanisms.

Answer 33

isolating mechanisms

Question 34

Scientists studying a group of related bird species on an island archipelago discover that these species are always more closely related to each other within an island than they are between any two islands. The most likely explanation for this result is that

each bird species became reproductively isolated by living on a different island, then later colonized the other islands and acquired new adaptations.

many ancestral bird species colonized each island.

one bird species colonized each island and then evolved into distinct species on that island through character displacement.

each bird species evolved different adaptations in allopatry and then colonized the other islands.

Answer 34

one bird species colonized each island and then evolved into distinct species on that island through character displacement.

Question 35

If two species are able to mate and produce a hybrid offspring which can mate with other hybrid offspring, but is unable to mate with either parent’s species, it is an example of

character displacement.

allopatric speciation.

sympatric speciation via polyploidy.

sympatric speciation via disruptive selection.

Question 36

The most common mechanism for sympatric speciation in plants is

polyploidy.

spontaneous mutation.

geographic isolation.

punctuated equilibrium.

Answer 36

polyploidy

Question 37

The biological species concept of Ernst Mayr cannot be applied to

sympatric organisms.

eukaryotic organisms.

asexually-reproducing organisms.

allopatric organisms.

Answer 37

asexually-reproducing organisms.

Question 38

Very rapid speciation occurred when cichlid fishes were isolated in Lake Victoria. More recently, widespread extinction occurred after

hybridization stopped.

fishing was prohibited.

artificial selection stopped.

introduction of the Nile perch.

Answer 38

introduction of the Nile perch.

Question 39

Lake Victoria is famous for its variety of cichlid fishes. In fact, they offer the most diverse assembly of vertebrates presently known to science. One trait that scientists have focused on as one possible reason for their adaptability is

a second set of scales that lie beneath the top outermost scales.
a second set of jaws in their throats.
gill arches that are not covered by an operculum, which prevents hiding places for gill parasites.
ability to change color in relationship to their environment.

Answer 39

a second set of jaws in their throats.

Question 40

Reinforcement is most likely to drive the evolution of

postzygotic isolating mechanisms, because hybrids have low fitness relative to the parents.

prezygotic isolating mechanisms, because selection favors alleles that prevent hybridization.

postzygotic isolating mechanisms, because selection acts after the formation of hybrids.

prezygotic isolating mechanisms, because selection favors alleles that promote hybridization.

Answer 40

prezygotic isolating mechanisms, because selection favors alleles that prevent hybridization.