Question 1

Which statement best describes the purpose of a phylogenetic tree in biology?

Accepted Answer

It is a hypothesis about the evolutionary relationships among organisms.

Question 2

In the hierarchical classification system, which of the following is the correct order from broadest to most specific?

Accepted Answer

Domain, Kingdom, Phylum, Class, Order, Family, Genus, Species

Question 3

Which of the following is true regarding the interpretation of branch lengths in a phylogenetic tree?

Accepted Answer

Branch length can represent the amount of genetic change in a lineage.

Question 4

A biologist is comparing DNA sequences between two species. She finds that the sequences are very similar. What can she most likely infer?

Accepted Answer

The two species share a recent common ancestor.

Question 5

Which of the following best defines a clade?

Accepted Answer

A group that includes an ancestor and all of its descendants.

Question 6

Which statement about sister taxa is correct?

Accepted Answer

Sister taxa are groups that share a common ancestor not shared by any other group.

Question 7

Why is it incorrect to assume that a taxon evolved from the taxon next to it on a phylogenetic tree?

Accepted Answer

Because the tree shows patterns of descent, not direct ancestry between adjacent taxa.

Question 8

Which of the following is NOT indicated by a phylogenetic tree?

Accepted Answer

When a species evolved

Question 9

A researcher rotates the branches of a phylogenetic tree around a branch point. What does this change?

Accepted Answer

It does not change the evolutionary relationships; only the visual arrangement.

Question 10

Which of the following is an example of a shared derived character used in cladistics?

Accepted Answer

The presence of feathers in birds.

Question 11

Which type of gene is most useful for inferring ancient evolutionary relationships?

Accepted Answer

Ribosomal RNA genes, because they evolve slowly.

Question 12

If two species have many orthologous genes, what does this suggest about their evolutionary history?

Accepted Answer

They share a common ancestor, even if they diverged long ago.

Question 13

Which of the following best describes a paraphyletic group?

Accepted Answer

A group that includes an ancestor and some, but not all, of its descendants.

Question 14

A scientist is using mitochondrial DNA to study evolutionary events. What type of events is she most likely investigating?

Accepted Answer

Recent evolutionary events.

Question 15

Which of the following is a correct statement about gene duplication and genome evolution?

Accepted Answer

Gene duplication increases the number of genes, providing opportunities for evolutionary change.

Question 16

Which formula would you use to calculate the percentage of orthologous genes shared between two species, given the number of shared orthologous genes $$N_{shared}$$ and the total number of genes $$N_{total} in $$one species?

Accepted Answer

$$\frac{N_{shared}}{N_{total}} 	imes 100$$

Question 17

Which scenario best illustrates convergent evolution?

Accepted Answer

Two unrelated species develop similar traits due to similar environmental pressures.

Question 18

A phylogenetic tree shows that sharks and mammals have been evolving for the same amount of time since their last common ancestor. What does this imply?

Accepted Answer

Both have been evolving for the same duration, but along different paths.

Question 19

Which of the following is a key difference between orthologous and paralogous genes?

Accepted Answer

Orthologous genes result from speciation events and are found in different species; paralogous genes result from gene duplication within a species.

Question 20

If a single human gene can encode multiple proteins with different functions in various tissues, what does this suggest about gene number and complexity?

Accepted Answer

Gene versatility can contribute to complexity without a proportional increase in gene number.

Phylogeny and the Tree of Life: Systematics, Taxonomy, and Evolutionary Relationships

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