UNIT #1 Quizzes Review (CH. 20, 22, & 23)

This is the flashcard set for chapter 20, 22, and 23 in my Biology textbook, taken from lecture quizzes on each chapter.

Darwin proposed that natural selection occurs in an environment by…

Favoring heritable features that make the organism better suited to survive and reproduce

A human autosomal recessive trait appears in 1 in 100 births. What percent of people are homozygous dominant for this gene?

81%

Female cardinals select male mates in part based on their bright red color. What effect would this have on a cardinal population?

The frequency of red alleles would be greater than those predicted by Hardy-Weinberg equilibrium

Which factor does NOT result in gene flow?

Disassortative mating within a population

Reproductive success of an individual is known as:

Fitness

There are more than 30 blood group genes in humans, in addition to the ABO locus, each with multiple alleles. This increases _______ in human populations

Genetic variability

__________ would keep a population in Hardy-Weinberg equilibrium.

Random mating

Different species of picture-winged fruit flies in the Hawaiian Islands are genetically similar to each other, yet genetically different from their ancestral population in Asia. This is probably an example of…

Founder effect

The recessive phenotype of a trait occurs in 16% of a population. What is the frequency of the dominant allele?

0.60

An insect population that becomes resistant to a plant's toxin is an example of…

Natural selection

Which statements about gradualism and punctuated equilibrium are true? Check all that apply.

B.) According to the theory of punctuated equilibrium, evolutionary change occurs only during brief periods of speciation, C.) Gradualism suggests that evolutionary change is not linked to speciation

Which statements about the Lake Victoria cichlid fishes are true? Check all that apply

A.) The adaptive radiation of the estimated 300 species of cichlid fish was very rapid and took place during the last 200,000 years, B.) The adaptive radiation of the Lake Victoria cichlids may have resulted from a key evolutionary innovation, C.) Many of the Lake Victoria cichlids have very specialized adaptations that allow them to occupy diverse habitats within the lake

Why do the Galápagos Islands and the Hawaiian Islands have so many endemic species of flies and birds? Check all that apply

A.) There are numerous islands in each archipelago, B.) There is adequate distance between islands to allow divergence, C.) The founder effect was common when islands were colonized

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

Allopatric

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

Sympatric species

Hybridization regularly occurs between three species of Darwin's finches on Daphne Major, but the finches are still considered different species because…

They occupy different niches

Once species have formed, they keep their identity by…

Isolating mechanisms

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

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

Punctuated equilibrium

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

The evolutionary sequence in the development of a complex character can be best analyzed through…

Synapomorphies

Phenotypic similarity does not always reflect evolutionary relationships due to…

Homoplasy

The following are steps used to construct a cladogram that best reflects the evolutionary relationships of a group of species. Which step involves deciding which tree is most likely to have occurred, based on the fewest character state changes?

Apply the principle of parsimony

Two bird species have different mating calls, occupy different habitats in nature, and when they hybridize, the hybrids are infertile. Which isolating mechanisms maintain these species?

Ecological isolation, behavioral isolation, and hybrid sterility

Evolution acts at the level of the…

Population

Punctuated equilibrium proposed by Eldredge and Gould in 1972 is an evolutionary process that involves…

"Spurts" of change observable in the fossil record followed by periods of stasis

Reinforcement is most likely to drive the evolution of…

Prezygotic isolating mechanisms, because selection favors alleles that prevent hybridization

Studies of snapping shrimp on either side of the Isthmus of Panama have shown that each Caribbean shrimp species is more closely related to a Pacific shrimp species than it is to any other Caribbean shrimp species. The most likely explanation for this result is…

Snapping shrimp species in each ocean diverged after the formation of the Isthmus of Panama

The most common mechanism for sympatric speciation in plants is…

Polyploidy

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

Five

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

Many species might coexist in a particular environment by occupying different ecological…

Niches

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…

Key innovation

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 led to behavioral isolation in Darwin's finches

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

Species

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

Postzygotic

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

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

Allopatric

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

Gradualism

Natural selection for a certain phenotype will affect the…

Allele frequency of a population

When fisheries managers move fish from one lake to another, this causes gene…

Flow

In the Hardy-Weinberg equation, p and q represent….

Allele frequencies

A restriction in genetic variability caused by a drastic reduction in population size is called a…

Bottleneck effect

For a gene with two alternative alleles, A (with a frequency of p) and a (with a frequency of q), the term in the algebraic form of the Hardy-Weinberg equilibrium for the heterozygote genotype frequency is…

2pq

The observation that many Native Americans have type O negative is best explained by…

Founder effect

Female cardinals select male mates in part based on their bright red color. What effect would this have on a cardinal population that was in Hardy-Weinberg equilibrium?

The frequency of red alleles would be greater than those predicted by Hardy-Weinberg equilibrium

About 80% of the alleles present in thoroughbred horses can be dated back to 31 known ancestors from the late eighteenth century. As a result, one would expect…

Little variation to select genes

If a population was in Hardy-Weinberg equilibrium then _____________________ would occur in that population.

No evolutionary changes

Characteristics between the branch points of a cladogram that are shared by all organisms above the branch point and are not present in any below it are called…

Derived characters

Characteristics that are present in organisms as a result of common evolutionary descent are said to be __________ characteristics

Ancestral

Derived character states shared by clade members are called…

Synapomorphies

Birds, snakes, lizards, turtles, and crocodiles are all thought to share a common ancestor and several homologous traits; assuming that this is true, these groups of animals and their common ancestor would represent…

A monophyletic group

Evidence suggests that the crocodiles are more closely related to the birds than turtles and snakes; if so, then including crocodiles, but not birds, in the Class Reptilia would make the Class Reptilia…

A paraphyletic group