Question 1

Which of the following best explains why the rise of atmospheric O$$_2$$ about 3 billion years ago led to both mass extinctions and the evolution of more complex life forms?

Accepted Answer

O$$_2$$ was toxic to most ancient organisms, causing many to go extinct, but it also enabled aerobic respiration, which releases more energy from organic molecules.

Question 2

The Cambrian explosion is characterized by which of the following?

Accepted Answer

A dramatic increase in animal diversity, including new body shapes and armor types, between 535 and 525 million years ago.

Question 3

Which of the following is the best example of adaptive radiation?

Accepted Answer

A single ancestral bird species colonizes several islands and evolves into multiple species, each adapted to a different ecological niche.

Question 4

Which event is most closely associated with the Permian mass extinction?

Accepted Answer

Massive volcanic eruptions that increased atmospheric CO$$_2$$ levels about 252 million years ago.

Question 5

In the long-term E. coli experiment, what was the main evolutionary outcome after 20,000 generations in a low-glucose medium?

Accepted Answer

The population evolved to reproduce almost twice as efficiently in low-glucose conditions.

Question 6

If you transfer E. coli populations evolved in low-glucose medium to a medium with a different carbon source, what is the most likely outcome?

Accepted Answer

Most populations will grow worse in the new medium due to specialization for low-glucose conditions.

Question 7

Which of the following best describes convergent evolution?

Accepted Answer

Distinct lineages evolve similar traits independently due to similar environmental pressures.

Question 8

How can biologists distinguish between migration and convergent evolution when similar organisms are found on different islands?

Accepted Answer

By comparing DNA sequences to construct phylogenetic trees and estimate the number of independent evolutionary events.

Question 9

Which of the following is a correct statement about sexual reproduction and evolution?

Accepted Answer

Sexual reproduction increases genetic diversity by shuffling alleles and generating new mutations.

Question 10

Which of the following scenarios best illustrates the concept of a population specializing in a stable environment?

Accepted Answer

A population of insects evolves resistance to a specific pesticide used consistently over many generations.

Question 11

Which of the following is the best definition of a phylogenetic tree?

Accepted Answer

A diagram that represents the evolutionary relationships among different species based on shared ancestry.

Question 12

Which of the following is a real-world example of convergent evolution?

Accepted Answer

The independent evolution of saber teeth in both Thylacosmilus (a marsupial) and Smilodon (a placental mammal).

Question 13

Which of the following best describes the process of adaptive radiation in Caribbean anole lizards?

Accepted Answer

A single ancestral species gives rise to multiple species, each adapted to a different ecological niche on the islands.

Question 14

Which of the following statements about mass extinctions is correct?

Accepted Answer

Mass extinctions are often followed by adaptive radiations, where surviving lineages diversify to fill available ecological niches.

Question 15

Given the following equation for aerobic respiration: $$\mathrm{C_6H_{12}O_6$ + 6O_2 ightarrow 6CO_2 + 6H_2O + 	ext{energy}}$$, what is the main evolutionary advantage of this process?

Accepted Answer

It allows organisms to extract much more energy from glucose compared to anaerobic processes.

Question 16

Which of the following best explains why phylogenetic trees are often difficult to construct with incomplete information?

Accepted Answer

Incomplete information can lead to uncertainty about the number and order of evolutionary changes, making it hard to infer accurate relationships.

Question 17

Which of the following is a likely consequence of climate change based on the fossil record and climate data?

Accepted Answer

Periods of rapid climate change are often associated with mass extinctions and shifts in biodiversity.

Question 18

Which of the following best describes the relationship between gene expression and the evolution of dramatic traits?

Accepted Answer

Changes in gene expression and regulation, especially during development, can lead to significant differences in traits among organisms.

Question 19

A researcher finds two species of lizards on different Caribbean islands that look very similar. Which evidence would best support the hypothesis that their similarity is due to convergent evolution rather than migration?

Accepted Answer

DNA analysis shows that the two species are more closely related to other species on their own islands than to each other.

Evolution, Extinction, and Adaptive Radiation - Not on Exam 3

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