In the Darkest Depths

Although scientists in the early 1800s were unable to explore the deepest regions of the ocean, they Knew that sunlight could not penetrate depths greater than 275 meters Without sunlight, there can be no photosynthesis(the process by which plants convert sunlight into energy), and therefore no plants or algae to serve as food for other organisms. Since ocean depths can exceed 10, 000 meters, scientists hypothesized that the deepest areas of the ocean could not support life.

Throughout the nineteenth century, scientists exploring the ocean collected organisms from ever greater ocean depths. In an 1873 expedition, researchers aboard the ship HMS Challenger dragged an open-sided box suspended from the ship across the floor of the Atlantic Ocean. This box-known as a dredge-sample the sea floor in different parts of the ocean at depths of up to 4, 57 meters. The scientists were astonished to discover nearly 5,000 previously unknown Species. When it became clear that life flourished at depths beyond the penetration of light, scientists were forced to reject their earlier hypothesis that no life existed in the deep ocean waters. After discovering this rich abundance of deep sea life. scientists were faced with the need to understand how it could exist. The lack of light suggested that deep-sea organisms were somehow sustained by energy that did not come from photosynthesis on the ocean floor. Scientists had observed that the surface waters of the ocean produced a steady descent of tiny particles that were produced by the death and decomposition of organisms living there. These particles are known as”marine snow. Large organisms such as whales also occasionally died and fell to the ocean floor. Scientists hypothesized that marine snow and the remains of large organisms provided the energy needed to sustain organisms in the depths of the ocean.

In the 1970s, scientists were finally able to send submersibles-small manned submarines-to take a first-hand look at the deepest ocean areas. Their discoveries were striking. They not only confirmed that much of the ocean floor supported living organisms but that areas near openings in the floor of the ocean, which later came to be known as hydrothermal Vents, contained a great diversity of deep-sea species. Hydrothermal vents release plumes of hot water with high concentrations of sulfur compounds and other mineral nutrients. A tremendous diversity of species surrounded these hydrothermal vents. Indeed, the total amount of life at these depths rivaled that seen in some of the most diverse places on Earth. It became clear that the amount of energy contained in organic matter resting on the sea floor was not sufficient to support such a diverse and abundant set of life forms. That earlier hypothesis now had to be rejected.

How could so much life exist at the bottom of the ocean? That this life existed near the hydrothermal vents suggested that the vents were somehow responsible. Scientists had known for a long time that some species of bacteria could obtain their energy from chemicals rather than from the Sun. The bacteria use the energy in chemical bonds, combined with carbon dioxide( CO2), to produce organic compounds-a process known as chemosynthesis-similar to the way that plants and algae use the energy of the Sun and CO2, to produce organic compounds through photosynthesis. Based on this knowledge, scientists hypothesized that the hot vents, which release water With dissolved hydrogen sulfide gas and other chemicals, provided a source of energy for bacteria and that these bacteria could be consumed by the other organisms living around the vents.

After several years of investigations, scientists found that the immediate area around the hot vents contained a group of organisms known as tube worms. These animals have no digestive system, but possess specialized organs that house vast numbers of bacteria that live in a symbiotic(mutually beneficial)relationship with the tube worms. The tube worms capture the sulfide gases and CO> from the surrounding water and pass these compounds to the bacteria, which then use the sulfide gases and CO2 to produce organic compounds. Some of these organic compounds are passed o the tube worms, which use them as food. These bacteria also represent a food source for many of the other animals that live near the vents. In turn, these bacteria-consuming animals can be consumed by larger animals.

 

1

Although scientists in the early 1800s were unable to explore the deepest regions of the ocean, they Knew that sunlight could not penetrate depths greater than 275 meters Without sunlight, there can be no photosynthesis(the process by which plants convert sunlight into energy), and therefore no plants or algae to serve as food for other organisms. Since ocean depths can exceed 10, 000 meters, scientists hypothesized that the deepest areas of the ocean could not support life.

According to paragraph 1, all of the following are true of the deepest ocean regions EXCEPT

AThey could not be studied in the early 1800s

BPhotosynthesis cannot take place there

CScientists in the early 1800s hypothesized that a source of food other than plants or algae existed there

DThey extend to depths greater than 10,000 meters

 

2

Throughout the nineteenth century, scientists exploring the ocean collected organisms from ever greater ocean depths. In an 1873 expedition, researchers aboard the ship HMS Challenger dragged an open-sided box suspended from the ship across the floor of the Atlantic Ocean. This box-known as a dredge-sample the sea floor in different parts of the ocean at depths of up to 4, 57 meters. The scientists were astonished to discover nearly 5,000 previously unknown Species. When it became clear that life flourished at depths beyond the penetration of light, scientists were forced to reject their earlier hypothesis that no life existed in the deep ocean waters. After discovering this rich abundance of deep sea life. scientists were faced with the need to understand how it could exist. The lack of light suggested that deep-sea organisms were somehow sustained by energy that did not come from photosynthesis on the ocean floor. Scientists had observed that the surface waters of the ocean produced a steady descent of tiny particles that were produced by the death and decomposition of organisms living there. These particles are known as”marine snow. Large organisms such as whales also occasionally died and fell to the ocean floor. Scientists hypothesized that marine snow and the remains of large organisms provided the energy needed to sustain organisms in the depths of the ocean.

In paragraph 2, the author reports the findings of the 1873 expedition of the HMS Challenger in order to

Ademonstrate the creativity involved in the invention of the dredge or studying the ocean floor

Bhelp explain why scientists no longer accepted the hypothesis at deep ocean waters were unable to support life

Cdocument the success of nineteenth-century explorations of the ocean’s depths

Destablish the fact that the ocean floor was at least 4, 572 meters deep

 

3

Throughout the nineteenth century, scientists exploring the ocean collected organisms from ever greater ocean depths. In an 1873 expedition, researchers aboard the ship HMS Challenger dragged an open-sided box suspended from the ship across the floor of the Atlantic Ocean. This box-known as a dredge-sample the sea floor in different parts of the ocean at depths of up to 4, 57 meters. The scientists were astonished to discover nearly 5,000 previously unknown Species. When it became clear that life flourished at depths beyond the penetration of light, scientists were forced to reject their earlier hypothesis that no life existed in the deep ocean waters. After discovering this rich abundance of deep sea life. scientists were faced with the need to understand how it could exist. The lack of light suggested that deep-sea organisms were somehow sustained by energy that did not come from photosynthesis on the ocean floor. Scientists had observed that the surface waters of the ocean produced a steady descent of tiny particles that were produced by the death and decomposition of organisms living there. These particles are known as”marine snow. Large organisms such as whales also occasionally died and fell to the ocean floor. Scientists hypothesized that marine snow and the remains of large organisms provided the energy needed to sustain organisms in the depths of the ocean.

It can be inferred from paragraph 2 that the discovery of abundant deep-sea organisms led scientists to consider which of the following questions?

AHow were deep-sea organisms able to reach the surface waters of the ocean?

BWas there enough light on the ocean floor for photosynthesis to occur?

CWhat caused “marine snow” to develop in the surface waters of the ocean?

DWhat was the source of energy on the ocean floor?

 

4

In the 1970s, scientists were finally able to send submersibles-small manned submarines-to take a first-hand look at the deepest ocean areas. Their discoveries were striking. They not only confirmed that much of the ocean floor supported living organisms but that areas near openings in the floor of the ocean, which later came to be known as hydrothermal Vents, contained a great diversity of deep-sea species. Hydrothermal vents release plumes of hot water with high concentrations of sulfur compounds and other mineral nutrients. A tremendous diversity of species surrounded these hydrothermal vents. Indeed, the total amount of life at these depths rivaled that seen in some of the most diverse places on Earth. It became clear that the amount of energy contained in organic matter resting on the sea floor was not sufficient to support such a diverse and abundant set of life forms. That earlier hypothesis now had to be rejected.

According to paragraph 3, all of the following are true about hydrothermal vents EXCEPT

AThey were discovered in the 1970s when scientists were able to send submersibles to the deepest areas of the ocean

BThey increase species diversity by releasing plumes that bring surface organisms to the ocean floor

CThey supply various nutrients to the surrounding water

DThey have as many different species of organisms as are found in the most diverse places on Earth

 

5

How could so much life exist at the bottom of the ocean? That this life existed near the hydrothermal vents suggested that the vents were somehow responsible. Scientists had known for a long time that some species of bacteria could obtain their energy from chemicals rather than from the Sun. The bacteria use the energy in chemical bonds, combined with carbon dioxide( CO2), to produce organic compounds-a process known as chemosynthesis-similar to the way that plants and algae use the energy of the Sun and CO2, to produce organic compounds through photosynthesis. Based on this knowledge, scientists hypothesized that the hot vents, which release water With dissolved hydrogen sulfide gas and other chemicals, provided a source of energy for bacteria and that these bacteria could be consumed by the other organisms living around the vents.

Which of the sentences below best expresses the essential information in the highlighted sentence in the passage? Incorrect choices change the meaning in important ways or leave out essential information.

AOrganic compounds are produced in both chemosynthesis and photosynthesis, making the bacteria similar to plants and algae in the way they use carbon dioxide

BCarbon dioxide and the Suns energy are combined in the process of photosynthesis, as well as in a process known as chemosynthesis, to produce chemical compounds

CMuch like plants and algae use the Suns energy in photosynthesis, the bacteria can produce organic compounds from the energy in chemical compounds through chemosynthesis

DThe bacteria, like plants and algae, require organic compounds that are formed when carbon dioxide and energy are combined n either chemosynthesis or photosynthesis

 

6

How could so much life exist at the bottom of the ocean? That this life existed near the hydrothermal vents suggested that the vents were somehow responsible. Scientists had known for a long time that some species of bacteria could obtain their energy from chemicals rather than from the Sun. The bacteria use the energy in chemical bonds, combined with carbon dioxide( CO2), to produce organic compounds-a process known as chemosynthesis-similar to the way that plants and algae use the energy of the Sun and CO2, to produce organic compounds through photosynthesis. Based on this knowledge, scientists hypothesized that the hot vents, which release water With dissolved hydrogen sulfide gas and other chemicals, provided a source of energy for bacteria and that these bacteria could be consumed by the other organisms living around the vents.

According to paragraph 4, the information that there were species of bacteria that obtained energy from chemicals was important because

Ait helped explain how hot vents could support organisms living near these openings

Bit provided a clearer understanding of how photosynthesis occurs in plants and algae

Cit demonstrated that plants, algae, and bacteria were all similar and related to one another

Dit established the role of carbon dioxide in both of the processes of chemosynthesis and photosynthesis

 

7

After several years of investigations, scientists found that the immediate area around the hot vents contained a group of organisms known as tube worms. These animals have no digestive system, but possess specialized organs that house vast numbers of bacteria that live in a symbiotic(mutually beneficial)relationship with the tube worms. The tube worms capture the sulfide gases and CO> from the surrounding water and pass these compounds to the bacteria, which then use the sulfide gases and CO2 to produce organic compounds. Some of these organic compounds are passed o the tube worms, which use them as food. These bacteria also represent a food source for many of the other animals that live near the vents. In turn, these bacteria-consuming animals can be consumed by larger animals.

The word “immediate” in the passage is closest in meaning to

Anearest

Bactive

Cvisible

Dlarge

 

8

After several years of investigations, scientists found that the immediate area around the hot vents contained a group of organisms known as tube worms. These animals have no digestive system, but possess specialized organs that house vast numbers of bacteria that live in a symbiotic(mutually beneficial)relationship with the tube worms. The tube worms capture the sulfide gases and CO> from the surrounding water and pass these compounds to the bacteria, which then use the sulfide gases and CO2 to produce organic compounds. Some of these organic compounds are passed o the tube worms, which use them as food. These bacteria also represent a food source for many of the other animals that live near the vents. In turn, these bacteria-consuming animals can be consumed by larger animals.

According to paragraph 5, which of the following happens in tube worms specialized organs?

AThe tube worms destroy vast numbers of bacteria

BThe tube worms capture smaller animals for food

CBacteria produce organic compounds from sulfide gases

DSulfide gases are produced with the help of CO2.

 

9

Throughout the nineteenth century, scientists exploring the ocean collected organisms from ever greater ocean depths. In an 1873 expedition, researchers aboard the ship HMS Challenger dragged an open-sided box suspended from the ship across the floor of the Atlantic Ocean. This box-known as a dredge-sample the sea floor in different parts of the ocean at depths of up to 4, 57 meters. The scientists were astonished to discover nearly 5,000 previously unknown Species. When it became clear that life flourished at depths beyond the penetration of light, scientists were forced to reject their earlier hypothesis that no life existed in the deep ocean waters. After discovering this rich abundance of deep sea life. scientists were faced with the need to understand how it could exist. The lack of light suggested that deep-sea organisms were somehow sustained by energy that did not

Look at the four squaresthat indicate where the following sentence could be added to the passage

But these were not the only source of organic material.

Where would the sentence best fit？Click on a square  sentence to the passage.

10

Scientists have long been fascinated by the deep, dark ocean and what life exists there.

AScientists in the early 1800s tried to understand how plants and algae could survive at depths below 275 meters, but it was not until later in that century that explorations provided answers.

BAfter the explorations of the 1970s, scientists rejected their earlier hypothesis and theorized that hydrothermal vents could be a source of energy for deep-sea organisms.

CBecause of the almost complete absence of sunlight at the ocean bottom, bacteria pose a greater danger to organisms there than they do to organisms living near the surface.

DExplorations of the ocean floor revealed an abundance of species at great depths that scientists at first believed were sustained by decomposing organisms that fell to the ocean floor.

EThe use of submersibles showed that the most species-diverse places on Earth are at the bottom of the ocean where minerals and other chemicals are present in higher concentrations than on land.

FBacteria that perform chemosynthesis near hydrothermal vents provide food for animals, some of which themselves become food for other animals.

 

答案请付费后查阅：