Question 1

Which of the following best explains the evolutionary transition from a jaw joint made of multiple bones to a jaw joint made of only the dentary and squamosal bones in mammals?

Accepted Answer

It allowed for more efficient sound transmission and improved hearing in mammals.

Question 2

Which evidence supports the endosymbiotic origin of mitochondria and chloroplasts in eukaryotic cells?

Accepted Answer

Both organelles have double membranes, their own DNA, and ribosomes similar to those of bacteria.

Question 3

Which of the following is NOT a characteristic of prokaryotic cells?

Accepted Answer

Presence of a nucleus

Question 4

A scientist discovers a fossil with a jaw joint composed of the dentary and squamosal bones, and the quadrate and articular bones are reduced and associated with the middle ear. What does this suggest about the fossil?

Accepted Answer

It is likely a mammal or a close mammalian ancestor.

Question 5

Which of the following best describes adaptive radiation?

Accepted Answer

The rapid diversification of a lineage into multiple new species, often following the opening of new ecological niches.

Question 6

Which feature distinguishes eukaryotic cells from prokaryotic cells?

Accepted Answer

Presence of internal membrane-bound organelles such as the nucleus and Golgi apparatus.

Question 7

Which of the following is a direct result of changes in the regulation of Hox genes during development?

Accepted Answer

Major changes in body form, such as the development of extra limbs or altered segment identity.

Question 8

Which of the following statements about the fossil record is correct?

Accepted Answer

It provides evidence for gradual transitions in anatomical features over time.

Question 9

A mutation causes a Hox gene to be expressed in the wrong body region of a fruit fly, resulting in legs growing where antennae should be. What does this demonstrate?

Accepted Answer

Changes in the timing and location of gene expression can drastically alter body plans.

Question 10

Which of the following best explains why mitochondria and chloroplasts have their own ribosomes and DNA?

Accepted Answer

They originated as free-living bacteria that were engulfed by ancestral eukaryotic cells.

Question 11

Which of the following is a likely consequence of a mass extinction event?

Accepted Answer

An increase in adaptive radiations as surviving groups diversify to fill vacant ecological niches.

Question 12

Which of the following is a key difference between aerobic bacteria and photosynthetic bacteria?

Accepted Answer

Aerobic bacteria have enzymes for O$$_2$$ metabolism, while photosynthetic bacteria have enzymes for photosynthesis.

Question 13

Which of the following best describes the process of endosymbiosis?

Accepted Answer

A larger cell engulfed a smaller prokaryote, which then lived inside the host cell and evolved into an organelle.

Question 14

Which of the following is a real-world example of adaptive radiation?

Accepted Answer

The diversification of mammals after the extinction of the dinosaurs.

Question 15

Which of the following is a characteristic of eukaryotic ribosomes?

Accepted Answer

They are large (80S) and found in the cytoplasm and on the rough endoplasmic reticulum.

Question 16

Which of the following statements about Hox genes is correct?

Accepted Answer

They determine the body plan by controlling the timing and location of gene expression during development.

Question 17

Which of the following best explains why the quadrate and articular bones are found in the middle ear of mammals?

Accepted Answer

They were repurposed from the jaw joint to transmit sound, improving hearing.

Question 18

Which of the following is a consequence of turning the wrong Hox gene on at the wrong time in the wrong place?

Accepted Answer

Development of abnormal body structures, such as legs in place of antennae.

Question 19

Which of the following is a feature shared by mitochondria, chloroplasts, and bacteria, supporting the endosymbiotic theory?

Accepted Answer

Presence of circular DNA and small (70S) ribosomes.

Major Events in the History of Life: Fossil Record, Cell Evolution, Adaptive Radiations, and Developmental Genes

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