Chapter 26 Homework and Dynamic Study Module: Taxonomy

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

In the two-kingdom system, why were fungi classified in the kingdom Plantae?

They are sedentary

There is(are) _____ eukaryotic domain(s).

One: The only eukaryotic domain is the domain Eukarya.

Animals that possess homologous structures probably

__________.

Evolved from the same ancestor: Homologous structures are similar because of common ancestry.

Fossil evidence indicates that some dinosaurs had feathers. If birds are indeed descended from dinosaurs, feathers are what kind of character?

Shared ancestral character:

-A shared ancestral character is one that originated in an ancestor of the taxon. In this case it appears that feathers originated in some dinosaur lineages and were passed down to birds.

Molecular clocks are based on the idea that __________.

On average, neutral mutations arise at a constant rate

-The idea of a molecular clock rests on the assumption that neutral mutations can arise and become fixed in populations. The rate of occurrence of these mutations is not affected by natural selection, so it is assumed that the rate is relatively constant over time.

In the figure, which similarly inclusive taxon is represented as descending from the same common ancestor as Canidae?

Mestelidae

Three living species X, Y, and Z share a common ancestor T, as do extinct species U and V. A grouping that consists of species T, X, Y, and Z (but not U or V) makes up

a paraphyletic group.

If organisms 1, 2, and 3 belong to the same class but to different orders and if organisms 3, 4, and 5 belong to the same order but to different families, which of the following pairs of organisms would be expected to show the greatest degree of morphological homology?

4 and 5

The term convergent evolution is most applicable to which of the following characteristics?

the wing of a bat and the wing of a chicken

Which of the following pairs is the best example of homologous structures?

bones in the bat wing and bones in the human forelimb

Which of the following conclusions regarding the phylogeny of these organisms can be made from this tree?

D is more closely related to E than it is to G

Cyanobacteria were once called blue-green algae because they are photosynthetic. According to the phylogeny shown, to which of the following organisms are the cyanobacteria more closely related?

Gram Positive Bacteria

From which taxon did mitochondria evolve?

Bacteria

The kingdom Monera was dismantled because of which of the following reasons?

Monera contained organisms from other domains

Which branch point represents the most recent common ancestor of all bears?

Branch Point 1

Which branch point represents the most recent common ancestor of the sloth bear and the spectacled bear?

Branch point 2

Which branch point represents the most recent common ancestor of the Asian black bear and the brown bear?

Branch point 4

Which species is the basal taxon in this tree?

Giant Panda

Identify the sister taxon to the polar bear.

Brown bear

According to this tree, is the sun bear more closely related to the sloth bear or the polar bear?

Polar Bear

The tree includes the most recent common ancestor of all living species of bears (branch point 1). What does this tell you about this phylogenetic tree?

This phylogenetic tree is rooted.

Which of the following groups of species is a monophyletic group, or clade?

sun bear, Asian black bear, American black bear, ancestral species 5, ancestral species 6

-This is a monophyletic group, or clade, because it includes ancestral species 5, the common ancestor of all taxa in the clade, and all of its descendents.

A study published in 2000 sequenced part of the mitochondrial cytochrome b gene from 61 brown bears from two sites in Alaska. One population of brown bears lives on the coastal mainland of Alaska, while a separate population lives on the ABC islands in southeastern Alaska.

Mainland and ABC brown bears differ by 11 fixed nucleotide substitutions in the cytochrome b gene. This suggests that the two brown bear populations represent genetically unique clades.

The researchers compared the cytochrome b sequences of the two clades of Alaskan brown bears to those of 55 polar bears. The analysis showed that polar bears and ABC brown bears differ at only three nucleotides in this gene, whereas polar bears and mainland brown bears had more differences.

Based on the results of the 2000 study, how should the portion of the tree extending from branch point 7 be altered?

Based on the revised branch of the tree, what kind of group do brown bears plus ancestral species 7 represent?

a paraphyletic group

Three living species X, Y, and Z share a common ancestor T, as do extinct species U and V. A grouping that consists of species T, X, Y, and Z (but not U or V) makes up __________.

a paraphyletic group

By applying a molecular clock, researchers have proposed that the first HIV-1 M invasion into humans occurred in the __________.

1930s

Which of the following is a true statement concerning horizontal gene transfer?

Horizontal gene transfer is known to occur within both prokaryotes and eukaryotes.

In a cladistic approach to systematics, an outgroup is __________.

a species or group of species from an evolutionary lineage that is known to have diverged before the lineage that includes all the species under study

Looking at the character table and phylogenetic tree above, which of the following is a true statement?

A backbone is a shared ancestral character in mammals (leopard).

Which of the following best summarizes the neutral theory?

Darwinian selection does not influence a lot of evolutionary change in genes and proteins because many of these changes do not affect fitness.

The term polytomy refers to a situation in which __________.

there is a branch point on a phylogeny from which more than two descendent groups emerge

Using cladistic analysis, a taxonomist wishes to construct a phylogenetic tree showing the relationships among various species of mammals. Which of the following would be the least useful for this purpose?

The fact that all mammals have hair

Which of the following is an assumption that should be made when reading a phylogenetic tree?

None of the listed assumptions should be made.

If you wanted to determine the lineage of plants that have evolved on a relatively young archipelago—approximately 15,000 years old—what type of nucleic acid should you compare?

mtDNA

The principle of maximum parsimony is applied to the process of constructing a phylogenetic tree in what way?

The tree that requires the fewest evolutionary events, as measured by the origin of shared derived characters, is selected.

Rabbits and guinea pigs both belong to class Mammalia. This means they must also both belong to __________.

phylum Chordata

What is the basis for the use of a molecular clock to determine the absolute time of evolutionary change?

Nucleotide substitutions in a gene occur at a relatively constant rate.

Sister taxa on a phylogenetic tree are defined as groups that __________.

share an immediate common ancestor and are each other’s closest relatives

A phylogenetic tree of bird families constructed by cladistic analysis would be a hypothesis about which of the following?

Evolutionary relationships among bird families

The binomial system assigns to each organism a unique name that describes its __________.

genus and species

Why are phylogenetic trees considered hypotheses?

A phylogenetic tree can be used to make testable predictions.

In cladistics, biologists attempt to place species into groups that each include an ancestral species and all of its descendants. A group that is paraphyletic fails to accomplish this goal in what way?

It consists of an ancestral species and some, but not all, of its descendants.

The idea of using molecules as clocks to time evolutionary events is very attractive, but there are many problems in actually applying the technique. What seems to be the best way to get reliable results?

It is important to use as many genes as possible. With this approach, fluctuations in evolutionary rate will tend to average out.

Two genes are recognized as orthologous if __________.

they are homologous genes found in different species, and their divergence traces back to speciation events that produced the species

A bald eagle and a black bear both have four limbs with digits because they are both tetrapods, descendants of a four-limbed ancestor. In this comparison, the limbs of the eagle and the bear are what type of structure?

Homologous

Birds and mammals have a four-chambered heart, but most reptiles have a three-chambered heart. How does this fact affect the construction of phylogenetic trees for these groups?

The most likely tree is not always the most parsimonious.

Researchers can use molecular homologies to __________.

reveal the number of mutations in a particular sequence that has occurred in each species since they diverged from a common ancestor

What is the relationship between systematics and taxonomy?

Systematics is a discipline within taxonomy.

What is a primary reason why a three-domain taxonomic scheme has been adopted over the previous five-kingdom taxonomic scheme?

Phylogenies based on genetic data revealed that some prokaryotes (kingdom Monera) differ as much from each other as they differ from eukaryotes.

Which of the following is the correct order of taxonomic levels in the Linnean system of classification, from most to least inclusive?

Domain, kingdom, phylum, class, order, family, genus, species

A taxon __________.

is a formal grouping at any given level

Which of the following would be the least useful in determining the relationships among various species?

Analogous structures

The separate lineages leading to dolphins and sharks both evolved streamlined bodies, dorsal fins, and broad tail fins as adaptations to efficient locomotion in a marine environment. In this comparison, the bodies and fins of dolphins and sharks are what type of structures?

Analogous