Question 1

Which of the following best explains why the frequency of blue-flowered lacecap hydrangeas will not increase over time, even though pollinators prefer blue flowers?

Accepted Answer

The blue flower trait is not genetically determined; it is influenced by soil pH.

Question 2

A population of white moths living on birch trees becomes exposed to pollution, turning the tree trunks black. What is the most likely outcome for this population, and why?

Accepted Answer

The population will most likely go extinct because there is no genetic variation for dark coloration.

Question 3

Which process does NOT create new genetic variation in a population?

Accepted Answer

Natural selection

Question 4

Why are the silversword and mountain dubautia more genetically similar to each other than to the queen of the Andes, despite the queen of the Andes occupying a similar habitat?

Accepted Answer

Geographically close species tend to share a recent common ancestor.

Question 5

What evolutionary concept is illustrated by the similarity in DNA between South American alpine and lowland forest plants, despite their different habitats?

Accepted Answer

Genetic similarity is determined more by ancestry than by habitat.

Question 6

Which of the following best describes a ring species?

Accepted Answer

A species with populations distributed in a ring, where neighboring populations can interbreed but distant ones cannot.

Question 7

The pentadactyl limb in vertebrates is considered evidence for evolution because:

Accepted Answer

It shows structural similarity due to common ancestry, despite different functions.

Question 8

Why do embryos of birds, cats, and humans all have gill slits and tails at some stage of development?

Accepted Answer

They inherit alleles from aquatic ancestors, reflecting shared ancestry.

Question 9

Which of the following is an example of a vestigial structure?

Accepted Answer

A human tailbone

Question 10

What does the universality of the genetic code suggest about the origin of life on Earth?

Accepted Answer

All living things are descended from a common ancestor.

Question 11

If a mutation occurred in an aminoacyl-tRNA synthetase enzyme, what could be the consequence for the genetic code?

Accepted Answer

A codon could code for a different amino acid, altering many proteins.

Question 12

Which equation represents the DNA sequence that codes for the amino acid sequence Tryptophan - Tryptophan - Methionine - Tryptophan?

Accepted Answer

$$ ACCACCTACACC $$

Question 13

Why is the genetic code considered arbitrary?

Accepted Answer

Any codon could theoretically code for any amino acid.

Question 14

What is the main reason why code-altering mutations are almost always fatal?

Accepted Answer

They cause thousands of amino acid substitutions in most proteins.

Question 15

Which of the following is NOT a prediction of the hypothesis that species are related by evolutionary descent?

Accepted Answer

Species share the same (arbitrary) genetic code.

Question 16

In the yeast Candida albicans, the codon CUG codes for serine instead of leucine. What does this exception tell us about the genetic code?

Accepted Answer

The genetic code is highly conserved but rare exceptions exist.

Question 17

Which of the following best describes convergent evolution?

Accepted Answer

Unrelated species evolve similar traits due to similar environmental pressures.

Question 18

Which of the following statements about natural selection is TRUE?

Accepted Answer

Natural selection acts only on heritable genetic variation.

Question 19

Why do activation enzymes (aminoacyl-tRNA synthetases) play a critical role in maintaining the genetic code?

Accepted Answer

They ensure that each tRNA is paired with the correct amino acid.

Question 20

Which of the following is a real-world example of molecular homology supporting evolutionary theory?

Accepted Answer

A firefly gene inserted into a tobacco plant produces the same protein in both organisms.

Lec: 8 Evidence for Evolution: Biogeography and Homology

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