Question 1

Which of the following best describes a monophyletic group (clade) in a phylogenetic tree?

Accepted Answer

A group that includes all descendants of a common ancestor and only those descendants.

Question 2

When constructing a phylogenetic tree, which type of trait is most useful for identifying evolutionary relationships among taxa?

Accepted Answer

Synapomorphic traits

Question 3

A researcher finds that two species share a trait that is not present in their most recent common ancestor. What is the most likely explanation for this trait?

Accepted Answer

It is a result of convergent evolution.

Question 4

Which of the following statements about phylogenetic trees is correct?

Accepted Answer

They are hypotheses that can be refined as new data become available.

Question 5

Given the following character matrix for three taxa, which two taxa are most closely related?

Taxon A: 0 1 1
Taxon B: 0 1 0
Taxon C: 1 1 1

Accepted Answer

Taxon A and Taxon C

Question 6

Which event is most likely to result in adaptive radiation according to the fossil record?

Accepted Answer

A mass extinction that opens up ecological niches

Question 7

What is the primary difference between synapomorphic and convergent traits?

Accepted Answer

Synapomorphic traits are shared due to common ancestry, while convergent traits arise independently.

Question 8

If a phylogenetic tree is constructed using only morphological data, which limitation might affect its accuracy?

Accepted Answer

Convergent evolution may cause unrelated species to appear closely related.

Question 9

Which of the following best explains the importance of the fossil record in understanding evolutionary history?

Accepted Answer

It provides evidence for mass extinctions and adaptive radiations.

Question 10

A student is given a small set of character state data for four taxa. What is the best approach to infer their phylogenetic relationships?

Accepted Answer

Identify shared derived traits (synapomorphies) and construct a tree based on these.

Question 11

Which formula would you use to calculate the probability of extinction in a clade given a constant extinction rate $$\lambda$$ over time $$t$$?

Accepted Answer

$$P = 1 - e$$^{-\lambda t}$$

Question 12

Which scenario best illustrates background extinction?

Accepted Answer

A gradual loss of species due to ongoing environmental changes.

Question 13

If two organisms share a trait that is present in their most recent common ancestor, what is this trait called?

Accepted Answer

Homologous trait

Question 14

Which of the following is NOT a reason why phylogenetic trees are considered hypotheses?

Accepted Answer

They are always proven to be correct.

Question 15

A mass extinction event is followed by a rapid increase in species diversity. What is the most likely explanation for this pattern?

Accepted Answer

Adaptive radiation occurs as surviving species exploit new ecological niches.

Question 16

Which of the following is an example of a synapomorphy?

Accepted Answer

The presence of feathers in birds and their closest dinosaur relatives.

Question 17

Which process can lead to the formation of parallel traits in unrelated taxa?

Accepted Answer

Similar selective pressures in different environments.

Question 18

If a phylogenetic tree shows that whales and hippos share a more recent common ancestor with each other than with other mammals, what does this imply?

Accepted Answer

Whales and hippos are more closely related to each other than to other mammals.

Question 19

Which of the following best describes the effect of mass extinction on evolutionary history?

Accepted Answer

It removes many species, allowing survivors to diversify and fill new niches.

Question 20

Which of the following is a key insight gained from analyzing the fossil record?

Accepted Answer

Patterns of adaptive radiation and mass extinction events.

Phylogenetic Trees, Fossil Record, and Evolutionary Relationships

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