Question 1

The first cells were most likely heterotrophic anaerobes because:

Accepted Answer

The first cells were most likely heterotrophic anaerobes because they utilized preformed organic molecules and did not need oxygen. This is because the early Earth's atmosphere lacked oxygen, making it impossible for the first life forms to rely on oxygen for their metabolism.

Question 2

The atmosphere of early Earth is currently thought to have contained:

Accepted Answer

The atmosphere of early Earth is believed to have been devoid of oxygen and rich in gases like carbon dioxide, water vapor, carbon monoxide, hydrogen, and nitrogen. This composition is thought to have played a crucial role in the development of life on Earth, providing the necessary conditions for the synthesis of organic molecules. Oxygen only became a significant component of the Earth's atmosphere with the advent of photosynthesis.

Question 3

Who first proposed the concept that simple organic molecules could form spontaneously from simpler raw materials?

Accepted Answer

Oparin and Haldane independently proposed the concept that simple organic molecules could form spontaneously from simpler raw materials, laying the groundwork for theories on the origin of life.

Question 4

Which of the following suggest that the earliest cells were prokaryotic?

Accepted Answer

The answer of Which of the following suggest that the...

Question 5

What was a significant outcome of the Miller and Urey experiment?

Accepted Answer

The Miller and Urey experiment is significant because it demonstrated that organic molecules could be synthesized from inorganic materials under conditions thought to resemble those of early Earth. This provided evidence supporting the idea that the basic building blocks of life could have formed naturally.

Question 6

This period was characterized by the decline of some woody plants and the rise of herbaceous plants:

Accepted Answer

The answer of This period was characterized by the decline...

Question 7

One critical requirement for life to arise on Earth was time for which of the following to occur?

Accepted Answer

Molecules needed time to accumulate and react with one another to form complex organic compounds, which are essential for the development of life.

Question 8

Which of the following is NOT a requirement for the chemical evolution of life?

Accepted Answer

Carbon dioxide is not a requirement for the chemical evolution of life. The chemical evolution theory suggests that life began in an environment with little or no free oxygen, requiring a source of energy, availability of chemical building blocks, and time to allow for complex molecules to form. Carbon dioxide, while important for life as we know it, especially for photosynthesis in plants, is not a direct requirement for the initial chemical evolution of life.

Question 9

Which of the following statements is true?

Accepted Answer

The answer of Which of the following statements is true?
...

Question 10

Why is it believed that RNA was the first informational molecule to evolve?

Accepted Answer

RNA molecules have the unique ability to act as both catalysts (enzymes) and substrates for their own replication, which supports the RNA world hypothesis suggesting that RNA was the first informational molecule to evolve. This dual functionality could have allowed early RNA molecules to replicate and evolve without the need for proteins or DNA.

Question 11

Which hypothesis states that life developed from nonliving matter?

Accepted Answer

Chemical evolution refers to the hypothesis that life originated from nonliving chemical substances through a series of chemical reactions, leading to the formation of complex organic molecules.

Question 12

The atmosphere of early Earth did not include:

Accepted Answer

The early Earth's atmosphere was primarily composed of gases like carbon dioxide, water vapor, carbon monoxide, and nitrogen, but it lacked free hydrogen.

Question 13

Which scientist worked on the concept of simple organic molecules?

Accepted Answer

J.B.S. Haldane, along with Oparin, proposed the theory that life began in the early oceans of Earth through a process of chemical evolution involving simple organic molecules. This theory is a cornerstone in the study of abiogenesis, the origin of life from non-living matter.

Question 14

The iron-sulfur world hypothesis suggests that organic molecules formed near:

Accepted Answer

The iron-sulfur world hypothesis posits that life began at hydrothermal vents on the ocean floor, where mineral-laden water provides a rich source of chemicals. These conditions could have facilitated the formation of organic molecules necessary for life.

Question 15

Presently, it is thought that organic polymers may have formed and accumulated on:

Accepted Answer

Organic polymers, which are essential for the origin of life, are thought to have formed and accumulated on rocks and clay. These surfaces could have provided the necessary environment for complex organic molecules to assemble, due to their ability to adsorb organic compounds and catalyze polymerization reactions.

Question 16

Which of the following periods occurred during the Paleozoic era?

Accepted Answer

The Silurian period is part of the Paleozoic era, which spans from about 541 to 252 million years ago. The Ediacaran precedes the Paleozoic, while the Triassic, Jurassic, and Paleogene periods follow it.

Question 17

At what date were gymnosperms, large dinosaurs, and the first toothed birds common?

Accepted Answer

Gymnosperms, large dinosaurs, and the first toothed birds were common during the Mesozoic era, which spanned from about 252 to 66 million years ago. The date 201 million years ago (mya) falls within the early part of this era, specifically the late Triassic to early Jurassic period, making it the most accurate choice for when all three were common.

Question 18

Amino acids and other organic molecules were formed in the laboratory of Miller and Urey from which of the following?

Accepted Answer

The Miller-Urey experiment simulated early Earth conditions, using a mixture of hydrogen, methane, water, and ammonia, along with electrical discharges to mimic lightning. This setup led to the formation of amino acids and other organic molecules, demonstrating a possible pathway for the origin of life's building blocks.

Question 19

Stromatolites are rocklike columns composed of:

Accepted Answer

Stromatolites are formed by the layering of microbial biofilms, particularly cyanobacteria, which are photosynthetic prokaryotes, not eukaryotes or specific types of protists or heterotrophic organisms.

Question 20

What kind of organisms likely perished due to the increase of oxygen in the atmosphere three billion years ago?

Accepted Answer

Obligate anaerobes likely perished due to the increase of oxygen in the atmosphere three billion years ago because they cannot survive in the presence of oxygen.

Quiz 21: The Origin and Evolutionary History of Life