Question 1

Which of the following best describes the process of adaptive radiation?

Accepted Answer

The rapid evolution of diversely adapted species from a common ancestor following events such as mass extinction or colonization of new regions.

Question 2

According to the fossil record, which of the following factors is most likely to increase the likelihood that an organism will be fossilized?

Accepted Answer

Being abundant, widespread, and possessing hard parts such as shells or skeletons.

Question 3

Which event is most closely associated with the sudden appearance of many animal phyla in the fossil record?

Accepted Answer

The Cambrian explosion

Question 4

Which of the following is NOT a stage in the origin of life as hypothesized for early Earth?

Accepted Answer

Direct formation of multicellular organisms from inorganic compounds

Question 5

A scientist discovers a fossil containing a radioactive isotope with a half-life of 5,000 years. If the ratio of parent to daughter isotope is 1:3, how old is the fossil? Use the formula $$ t = n 	imes 	ext{half-life} $$ where $$ n  is $$the number of half-lives.

Accepted Answer

$$ t = 10,000 	ext{ years} $$

Question 6

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

Accepted Answer

Mitochondria have a double membrane and their own circular DNA similar to prokaryotes.

Question 7

Which process is most directly responsible for the formation of banded iron formations in Earth's early history?

Accepted Answer

Oxygenic photosynthesis producing $$ O_2$ $$ that reacted with dissolved iron.

Question 8

Which of the following statements about mass extinctions is TRUE?

Accepted Answer

Each mass extinction event has resulted in the loss of at least 50% of marine species.

Question 9

Which environmental change is most likely to result from the formation of a supercontinent such as Pangaea?

Accepted Answer

Colder and drier climate inland

Question 10

Which of the following best explains why the fossil record is biased?

Accepted Answer

Species that existed for a long time, were abundant and widespread, and had hard parts are more likely to be fossilized.

Question 11

Which of the following is a plausible explanation for the Permian mass extinction?

Accepted Answer

Extreme volcanism leading to global warming and ocean acidification.

Question 12

Which of the following is a key adaptation that allowed plants to colonize land?

Accepted Answer

Development of a vascular system for transporting materials.

Question 13

Which of the following statements about radiometric dating is correct?

Accepted Answer

Radiometric dating uses the known half-life of radioactive isotopes to estimate the age of fossils.

Question 14

Which of the following is a consequence of continental drift?

Accepted Answer

Allopatric speciation due to separation of landmasses.

Question 15

Which molecule is thought to have been the first genetic material, and why?

Accepted Answer

RNA, because it can both store genetic information and catalyze reactions as ribozymes.

Question 16

Which of the following best describes the role of meteorites in the origin of life on Earth?

Accepted Answer

Meteorites provided a source of organic molecules such as amino acids and nitrogenous bases.

Question 17

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

Accepted Answer

The diversification of mammals after the extinction of non-avian dinosaurs.

Question 18

Which of the following is a property of protocells that was critical for the origin of life?

Accepted Answer

Ability to replicate and carry out metabolism.

Question 19

Which of the following best explains why the current rate of extinction is considered alarming by scientists?

Accepted Answer

It is estimated to be 100 to 1,000 times higher than the typical background rate.

Question 20

Which of the following is a plausible scenario for the formation of organic macromolecules on early Earth?

Accepted Answer

Polymerization of monomers on hot sand, clay, or rock surfaces.

Chapter 25: The History of Life on Earth – Study Notes

Study Guide - Practice Questions

Study Guide - Flashcards