Question 1

Which group of tetrapods had the first examples of specialized teeth?

Accepted Answer

B

Question 2

If we visualize the time that has passed since the origin of our solar system and Earth,or about 4.6 billion years,as a one-hour clock,then out of one hour,prokaryotes have been present on the planet for about

Accepted Answer

Prokaryotes, the earliest and simplest forms of life, appeared on Earth relatively soon after the planet's formation. Given that Earth is about 4.6 billion years old, and prokaryotes are thought to have emerged around 3.5 to 3.8 billion years ago, they have been present for the majority of Earth's history. If we condense Earth's history into a one-hour clock, prokaryotes have been around for approximately 45 minutes of that hour, reflecting their long presence on the planet.

Question 3

Of the following,which is the most abundant source of fossil evidence?

Accepted Answer

Sedimentary rock is formed by the accumulation of sediments, including the remains of organisms, over time. As a result, it is the most abundant source of fossil evidence. Amber, mud, and ice can all preserve fossils, but they are not as common as sedimentary rock.

Question 4

If the half-life of carbon-14 is about 5,730 years,then a fossil that has 1/16th the normal proportion of carbon-14 to carbon-12 should be about how many years old?

Accepted Answer

The fossil's carbon-14 content is 1/16th the normal proportion, which means it has gone through four half-lives (since 2^4 = 16). Each half-life is 5,730 years, so the age is 4 times 5,730 years, which equals 22,900 years.

Question 5

The evolution of mammals from early tetrapods

Accepted Answer

The answer of The evolution of mammals from early tetrapods
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Question 6

Which event stimulated the rapid development of eukaryotes?

Accepted Answer

The addition of oxygen to the atmosphere stimulated the rapid development of eukaryotes, as it allowed for the evolution of oxidative phosphorylation and aerobic respiration, which provided more efficient energy production. Eukaryotes also developed more complex cellular structures and processes, such as the endomembrane system and cytoskeleton.

Question 7

Radiometric dating is based on the

Accepted Answer

Radiometric dating is based on the decay of radioactive isotopes. It uses the known half-life of isotopes to determine the age of rocks or fossils. This method is commonly used in dating geological materials such as rocks and minerals.

Question 8

A difficulty in presenting evidence for a sixth mass extinction is

Accepted Answer

The difficulty in presenting evidence for a sixth mass extinction includes the fact that tropical rain forests harbor many unknown species, making it challenging to accurately assess the full extent of species loss.

Question 9

The major evolutionary episode corresponding most closely in time with the formation of Pangaea was the

Accepted Answer

The formation of Pangaea occurred during the late Paleozoic era, specifically during the Permian period. This period was marked by the largest mass extinction event in Earth's history, known as the Permian-Triassic extinction event or the Great Dying. Approximately 96% of marine species and 70% of terrestrial species went extinct during this event. Therefore, the Permian extinctions best correspond in time with the formation of Pangaea.

Question 10

What is true of the fossil record of mammalian origins?

Accepted Answer

The fossil record of mammalian origins includes transitional forms that show the gradual evolution of specialized teeth, which is a key feature in the evolution of mammals.

Question 11

Which life form has been present on Earth the longest?

Accepted Answer

Microbes such as bacteria have been present on Earth for approximately 3.5 billion years, making them the life form that has been present on Earth the longest. Jawed vertebrates, such as fish and reptiles, have been present for approximately 450 million years, while humans have been present for only about 200,000 years. Single-celled eukaryotes, such as protists, have been present for about 2 billion years, which is still less than the time period of bacteria.

Question 12

Which statement about the atmosphere and life on Earth is correct?

Accepted Answer

Life on Earth is believed to have arisen before oxygen was present in the atmosphere. Early life forms were anaerobic, meaning they did not require oxygen for their metabolism. Oxygen began to accumulate in the Earth's atmosphere as a result of photosynthesis by these early life forms, particularly cyanobacteria, in a process known as the Great Oxygenation Event. This accumulation of oxygen drastically changed the Earth's atmosphere and allowed for the evolution of aerobic life forms that use oxygen to produce energy.

Question 13

Which of the following is a biological cause of extinctions?

Accepted Answer

The origin of new species can lead to competition for resources, potentially driving existing species to extinction.

Question 14

For purposes of differentiation,what is the unique feature of the jaw fossils of non-mammalian tetrapods?

Accepted Answer

The unique feature of the jaw fossils of non-mammalian tetrapods is that the lower jaw is composed of several bones, while in mammals it is a single bone (the dentary). This characteristic is known as "non-mammalian jaw articulation."

Question 15

If we visualize the time that has passed since the origin of our solar system and Earth,or about 4.6 billion years,as a one-hour clock,then out of one hour,multicellular eukaryotes have been present on the planet for about

Accepted Answer

If we visualize the time that has passed since the origin of our solar system and Earth, or about 4.6 billion years, as a one-hour clock, then multicellular eukaryotes have only been present on the planet for the last 15 minutes or 25% of the hour.

Question 16

Which effect of continental drift would allow scientists to track the history of life on the planet?

Accepted Answer

The continental drift could cause a change in distribution of extinct animals which means that scientists can track the history of life on Earth based on where these fossils are found. By studying the distribution of fossils, scientists can reconstruct how the continents were arranged in the past, and how they drifted apart over time.

Question 17

The first terrestrial organisms probably were considered which of the following?
1)burrowers
2)photosynthetic
3)multicellular
4)prokaryotes
5)eukaryotes
6)plants and their associated fungi

Accepted Answer

The first terrestrial organisms were likely prokaryotes, which are simple, single-celled organisms without a nucleus, and some of these early terrestrial life forms were probably photosynthetic, using sunlight to create energy.

Question 18

What is the benefit of using carbon in radioisotope dating,versus using other elements?

Accepted Answer

Carbon is a key component of organic molecules, making it ideal for dating once-living materials. Its shorter half-life allows for accurate dating of recent samples.

Question 19

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

Accepted Answer

The fossil record is more likely to include organisms that were abundant or lived for long periods because these organisms had a higher chance of being preserved as fossils. Organisms that lived for short periods or were rare are less likely to be found in the fossil record. Choices B and C are incorrect because the fossil record contains many organisms that are not alive today, reflecting the Earth's changing biodiversity over time. Choice D is incorrect because the Earth's climate and geography have changed significantly over time, so fossils can be found in locations that had very different environmental conditions when the organisms lived.

Question 20

If we visualize the time that has passed since the origin of our solar system and Earth,or about 4.6 billion years,as a one-hour clock,then out of one hour,humans have been present on the planet for about

Accepted Answer

Humans have been present on Earth for a very short fraction of the planet's history. If the Earth's history were compressed into one hour, modern humans (Homo sapiens) have been around for roughly 200,000 years, which is about 2/10ths of a second on this scale.

Quiz 23: Broad Patterns of Evolution