Question 1

Which of the following best explains why the pelvic bone in certain fish species has become smaller over thousands of years, as observed in the fossil record?

Accepted Answer

Natural selection favored individuals with smaller pelvic bones, leading to an increase in this trait over generations.

Question 2

A population of beetles has two alleles for a gene: $A$ and $a$. If the frequency of $A$ ($p$) is 0.7 and the frequency of $a$ ($q$) is 0.3, what is the expected frequency of heterozygotes under Hardy-Weinberg equilibrium?

Accepted Answer

$2pq = 0.42$

Question 3

Which of the following is an example of convergent evolution?

Accepted Answer

The similar gliding adaptations in sugar gliders (marsupials) and flying squirrels (eutherians).

Question 4

A scientist discovers a new plant species that can only reproduce with others of its kind, producing fertile offspring, but is morphologically indistinguishable from a related species. Which species concept is the scientist using to define the new species?

Accepted Answer

Biological species concept

Question 5

Which of the following mechanisms is most likely responsible for the rapid spread of antibiotic resistance in a bacterial population?

Accepted Answer

Natural selection acting on heritable variation in resistance

Question 6

Which of the following statements about the human genome is correct?

Accepted Answer

Approximately 44% of the human genome is made up of repetitive DNA, including transposable elements.

Question 7

A population of birds is split by the formation of a new river, preventing gene flow between the two groups. Over time, the two populations diverge genetically and can no longer interbreed. This is an example of:

Accepted Answer

Allopatric speciation

Question 8

Which of the following best describes the function of Hox (homeotic) genes in animal development?

Accepted Answer

They regulate the spatial and temporal expression of genes that control body plan development.

Question 9

A population of flowers has a high average heterozygosity. What does this indicate about the population?

Accepted Answer

There is a high level of genetic variation, providing 'genetic backup' for adaptation.

Question 10

Which of the following is a post-zygotic reproductive barrier?

Accepted Answer

Reduced hybrid fertility

Question 11

A mutation causes a single nucleotide change in a gene, resulting in a premature stop codon. What type of mutation is this?

Accepted Answer

Nonsense mutation

Question 12

Which of the following is an example of frequency-dependent selection?

Accepted Answer

Scale-eating fish being more successful when their mouth orientation is rare in the population

Question 13

Which of the following best describes the difference between monophyletic and polyphyletic groups in a phylogenetic tree?

Accepted Answer

A monophyletic group includes a common ancestor and all its descendants, while a polyphyletic group does not include the most recent common ancestor.

Question 14

Which of the following is a real-world example of the founder effect?

Accepted Answer

A small group of finches colonizes a new island, and their descendants have different allele frequencies than the original population.

Question 15

Which of the following is NOT a condition required for Hardy-Weinberg equilibrium?

Accepted Answer

Non-random mating

Question 16

Which of the following best explains why sickle-cell trait persists in certain human populations?

Accepted Answer

Heterozygote advantage, where individuals with one sickle-cell allele are more resistant to malaria.

Question 17

Which of the following is a direct result of unequal crossing over during meiosis?

Accepted Answer

Gene duplication, leading to new gene functions

Question 18

Which of the following is a key piece of evidence supporting the endosymbiotic origin of mitochondria?

Accepted Answer

Mitochondria have their own circular DNA similar to that of proteobacteria.

Question 19

Which of the following best describes the principle of maximum parsimony in phylogenetic analysis?

Accepted Answer

The tree that requires the fewest evolutionary changes is preferred.

Question 20

A hybrid zone between two frog species produces hybrids that are less fit than either parent species. Over time, the reproductive barriers between the two species become stronger. This is an example of:

Accepted Answer

Reinforcement

Exam 1 Lecture: Evolutionary Biology: Chapters 21–26 Study Guide

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