223SP Biology for Science Majors II: Exam I 223SP Biology for Science Majors II: Exam I

1. Introduction to MasteringBiology 2. Phylogeny 3. Broad Patterns of Evolution 4. The Origin of Species 5. Descent with Modification

In addition to naming species, Linnaeus also grouped species into a hierarchy of increasingly inclusive categories. The largest category that would include closely related species is the:

Domain

The various taxonomic categories (genera, classes, etc.) of the hierarchical classification system differ from each other on the basis of:

Their Inclusiveness

Linnaeus was a "fixist" who believed that species remained fixed in the form in which they had been created. Linnaeus would have been uncomfortable with:

Phylogenies

Sister taxa:

Represent groups of organisms that share an immediate common ancestor

What evidence suggests that limbless bodies are the result of convergent evolution of snakes and lizards?

Snakes and lizards with limbless bodies evolved from different ancestors of legged lizards.

Some molecular data place the giant panda in the bear family (Ursidae) but place the lesser panda in the raccoon family (Procyonidae). Consequently, the morphological similarities of these two species are probably due to:

Possession of Analogous Structures

The importance of computers and computer software to modern cladistics is most closely linked to advances in:

Molecular Genetics

A potential source of confusion in constructing a phylogeny tree is similarity between organisms that is due to:

Convergent Evolution

A shared ancestral character is:

A character that originated in an ancestor of two taxa

Which of the following are problematic when the goal is to construct phylogenies that accurately reflect evolutionary history?

Polyphyletic and paraphyletic taxa

Which of the following is true of all horizontally oriented phylogenetic trees, in which time advances to the right?

The common ancestor represented by the rightmost branch point existed more recently in time than the common ancestors represented at branch points located to the left.

When using a cladistic approach to systematics, which of the following is considered most important for classification?

Shared Derived Characters

Cladograms (a type of phylogenetic tree) constructed from evidence from molecular systematics are based on similarities in:

Mutations to Homologous Genes

According to the principle of maximum parsimony,

the preferred tree is the one that minimizes the amount of evolutionary change.

What kind of evidence has recently made it necessary to assign the prokaryotes to either of two different domains rather than assigning all prokaryotes to the same kingdom?

Molecular

Which kingdom has been replaced with two domains?

Monera (prokaryotes)

What evidence allowed biologists to conclude that classification of the tree of life required a three-domain system?

The phylogenetic tree of the three domains of life is based on sequence data for rRNA and other genes.

The kingdom Protista is obsolete because it contains members of how many other kingdoms?

Three

Reptiles first appeared during the \_____ era.

Paleozoic Era

We are living during the \_____era.

Cenozoic Era

Dinosaurs went extinct during the \_____.

Mesozoic Era

\_____ were the dominant vertebrate life form during the Paleozoic era.

Amphibians

Life arose during the \_____.

Precambian Era

Flowering plants first appeared during the \_____.

Mesozoic Era

The Mesozoic era began approximately \_____ million years ago.

251

The Precambrian time began at least \_____ million years ago.

4,600

Seed plants first appeared during the \_____.

Paleozoic Era

The first prokaryotic cells appeared during the \_____.

Precambrian Era

Animals first appeared during the \_____.

Precambrian Era

The Cenozoic era began approximately \_____ million years ago.

65

\_____ were the dominant vertebrate life form during the Mesozoic era.

Dinosaurs

Most modern animal phyla evolved during the \_____ era.

Paleozoic Era

Bony fish first evolved during the \_____ .

Paleozoic Era

What is true of the fossil record of mammalian origins?

It includes transitional forms with progressively specialized teeth.

The evolution of mammals from early tetrapods

is an example of macroevolution

Of the following, which is the most abundant source of fossil evidence?

sedimentary rock, because such rock forms in areas sediment moved by water can cause the burial of organisms

Radiometric dating is based on the:

decay of radioactive isotopes.

Which event stimulated the rapid development of eukaryotes?

addition of oxygen to the atmosphere

For purposes of differentiation, what is the unique feature of the jaw fossils of non-mammalian tetrapods?

The lower jaw is composed of several bones.

Which group of tetrapods had the first examples of specialized teeth?

Therapsids

Which of the following statements about the fossil record is correct?

The fossil record includes more organisms that were abundant, or lived for long periods on Earth, than it is with those that lived for short periods of time and then became extinct.

Which life form has been present on Earth the longest?

microbes such as bacteria

Which of the following statements about adaptive radiation is correct?

Adaptive radiation occurs within a single lineage.

Which organisms are not examples of an adaptive radiation?

Mammals and reptiles in the post-dinosaur age

True or false? Convergent evolution is said to have occurred if the mouse species on two islands with similar habitats are found to have similar characteristics even though they originated from different species that did not have these characteristics.

True

Which Anolis lizard ecomorph has long legs?

Trunk/ground

Which of the following statements about the evolution of Anolis lizards in the Caribbean islands is true?

The phylogeny of ecomorphs on a given island reveals that adaptive radiation has taken place.

What was the main selective pressure behind the evolution of different Anolis lizard species in the Caribbean?

Specific ecological niches

True or false? The evolution of different ecomorphs on the Caribbean islands is an example of stabilizing selection.

False

Select the statements about the K-T boundary that are true.

The K-T boundary dates to 65 million years ago (when the dinosaurs disappeared).

The K-T boundary in Zumaia, Spain is sharp--representing an abrupt change in the marine ecosystem.

The K-T boundary separates rock layers of the Cretaceous period from those of the Tertiary period.

How do foraminifera found in rock layers above the K-T boundary compare to those in rock layers below?

Foraminifera above the boundary are smaller and less diverse than those below.

Iridium is a component of cosmic dust that rains down upon the earth at a constant rate. Why did Luis Alvarez suggest measuring iridium levels in the K-T boundary?

He was looking for a way to determine how quickly the layer had been deposited.

The scientific community was slow to accept the asteroid impact hypothesis. Why?

At the time, most geologists thought that the Earth changed slowly and gradually, and not by major catastrophes.

Which evidence is consistent with the asteroid impact hypothesis?

spherules, glass-like beads in the K-T boundary layer

shocked quartz in the K-T boundary layer

iridium

tektites, a type of melted rock

What was the critical piece of evidence that supported the hypothesis that an asteroid struck Earth 65 million years ago?

the Chicxulub crater in Mexico

How could an asteroid impact kill off such a large number of different species all over the planet?

Tsunamis, landslides, earthquakes, and heat caused by the impact killed organisms near the site of impact.

The impact was so extreme that life at ground zero was vaporized.

Debris from the impact orbiting around the Earth shielded sunlight, halting photosynthesis.

Which characteristic was NOT advantageous for organisms in the million years after the catastrophic asteroid impact?

large body size

The major evolutionary episode corresponding most closely in time with the formation of Pangaea was the

Permian extinctions.

Which of the following is a biological cause of extinctions?

origin of new species

A difficulty in presenting evidence for a sixth mass extinction is

that tropical rain forests harbor many unknown species.

Adaptive radiation

allows new species to occupy different habitats.

The history of continental drift on Earth has

allowed for both speciation and extinction to occur.

Records of extinctions on the planet indicate that

although Earth has experienced five mass extinctions, the diversity of life appears to be greater now than ever before.

Upon being formed, oceanic islands, such as the Hawaiian Islands, should feature what characteristic, leading to which phenomenon?

a variety of empty ecological niches, leading to adaptive radiation

Hox genes are a group of related genes that

control the body plan of an embryo and are conserved across many taxonomic groups.

An organism has a relatively large number of Hox genes in its genome. Which of the following is true of this organism?

The organism has the genetic potential to have a relatively complex anatomy.

The loss of ventral spines by modern freshwater sticklebacks is due to natural selection operating on the phenotypic effects of Pitx1 gene

silencing (loss of expression)

What type of genes control how flower petals are arranged or where a set of wings on a bird will develop?

homeotic genes

During the Cambrian explosion, fossil evidence indicates a rapid and sudden diversification of more complex animals. However, fossils of Ediacaran animals from 30 million years prior to this demonstrate that genes to produce complex animals had already existed. What could explain this?

changes in the environment that brought about selective adaptations and evolution during the Cambrian, repurposing some gene regions through differential regulation

The existence of evolutionary trends, such as increasing body sizes among various horse species, is evidence that

in particular environments, similar adaptations can be beneficial in more than one species.

Which of the following statements about species, as defined by the biological species concept, is (are) correct?

I. Biological species are defined by reproductive isolation.

II. Biological species are the models used for grouping extinct forms of life.

III. The biological species is the largest unit of population in which successful interbreeding is possible.

I and III only

Two species of frogs belonging to the same genus occasionally mate, but the offspring fail to develop and hatch. What is the mechanism for keeping the two frog species separate?

The postzygotic barrier, reduced hybrid viability

Which of the following statements about speciation is correct?

Speciation is a basis for understanding macroevolution.

A species is represented by individuals that form a population

whose members have the ability to interbreed and produce viable, fertile offspring.

Which of the following reproductive types of isolation illustrates postzygotic barriers?

Hybrid breakdown

Which term is used to describe populations that live close enough to interbreed?

Sympatry

What prevents speciation from occurring in sympatric populations?

Gene flow

True or false? A mating between a tetraploid individual and a diploid individual produces biologically fit offspring

False

Which of the following statements about autopolyploid individuals is true?

They contain more than two haploid sets of chromosomes.

What would be the ploidy of the viable gametes produced by a tetraploid individual if nondisjunction of all chromosomes occurred in meiosis I?

Tetraploid

How can an allopolyploid plant become a biologically fit new species?

Nondisjunction event during mitosis

How many chromosomes would be found in an allopolyploid plant if its parents had diploid numbers of 2 and 10, respectively?

Haploid number of 6

Microevolution occurs

when species populations undergo changes in allele frequencies over time.

Among known plant species, which of these are the two most commonly occurring phenomena that have led to the origin of new species?


1. allopatric speciation
2. sympatric speciation
3. sexual selection
4. polyploidy

2. Sympatric Speciation


4. Polyploidy

The most likely explanation for the high rate of sympatric speciation that apparently existed among the cichlids of Lake Victoria in the past is

sexual selection.

More species tend to be found in regions subdivided by rivers, canyons, mountains, or other human-induced barriers because of

geographic isolation.

After geographic separation, what process would be the last step before reproductive isolation?

natural selection

How can reproductive barriers form between sympatric populations while their members stay in contact with them?

increased polyploidy

"Conventional wisdom holds that the development of separate species happens quickly, most often when populations become separated by a geographical barrier." This is called \________ speciation. "Even if these groups meet again and manage to mate before diverging too far from one another, their offspring will be unfit and die out." This is described as hybrid \________.

allopatric; breakdown

In the ocean, on either side of the Isthmus of Panama, are 30 species of snapping shrimp; some are shallow-water species, and others are adapted to deep water. There are 15 species on the Pacific side and 15 different species on the Atlantic side. The Isthmus of Panama started rising about 10 million years ago. The oceans were completely separated by the isthmus about 3 million years ago. Why should deepwater shrimp on different sides of the isthmus have diverged from each other earlier than shallow-water shrimp?

They have been geographically isolated from each other for a longer time.

A hybrid zone is properly defined as

an area where mating occurs between members of two closely related species, producing viable offspring.

Sexual selection in cichlids occurs by female mate choice and results in reproductive isolation when

under normal light, each species prefers males of their own species.

Two models for the speed of speciation are based on patterns in the fossil record. Which of the following statements describes the gradual model of evolution?

Species steadily diverge from one another.

Which of these should decline in hybrid zones where reinforcement is occurring?

gene flow between distinct gene pools

The most likely explanation for the recent decline in cichlid species diversity in Lake Victoria is

fusion.

Prokaryotic cells are found in the domain(s) \_____.

Bacteria and Archaea

In the five-kingdom system, prokaryotes are placed in the kingdom \_____.

Monera

A human is classified in domain \_____ and kingdom \_____.

Eukarya ... Animalia

A rose bush is classified in domain \_____ and kingdom \_____.

Eukarya ... Plantae

In the five-kingdom system, which kingdom consists primarily of unicellular eukaryotes?

Protista