Euglena : Ecosystem Engineers

In 1995 an extremophile, or organism that thrives in extreme environments, was discovered in the United States in a lake outside of Butte, Montana. The body of water where it lives, known as the Berkeley Pit, is a former open-pit copper mine that is slowly filling with groundwater that dissolves heavy metals like arsenic, cadmium, zinc, and aluminum from the mine’s 2,000-foot-deep surface; the dissolved metals mix with the water to form a toxic (poisonous) solution. The Berkeley Pit is the largest hazardous waste site targeted for cleanup in the United States. As 2.6 million gallons of groundwater seep into the pit every day, the toxic brew edges ever closer to spilling into the Clark Fork River, which makes its way to the Columbia River and out to the ocean, representing a massive-scale ecological threat to the fisheries and communities in these areas.

Though the water in the pit is as acidic as lemon juice and considered inhospitable to life, a novel species has emerged and is slowly but surely changing the lake’s toxic brew to one more habitable. An analytic chemist studying the lake noticed a clump of green slime floating in the lake and brought a sample to Dr. Grant Mitman of Montana Tech. Mitman brought his colleagues Don and Andrea Stierle into the lab, and they identified the slime as a colony of Euglena mutabilis , a single-celled organism that forms algae-like mats. How Euglena came to grow in the Berkeley Pit is unknown, although some attribute its spread to a flock of 350 snow geese that landed (and subsequently died) in the lake several months prior to the discovery of the organism. The geese may have carried reproductive material of the Euglena in their feces (waste matter).

Euglena are among the oldest organisms in the world, having survived since the time when conditions on Earth were not too dissimilar to those found in the Berkeley Pit- -ancient acidic oceans were full of heavy metals and other free- floating elements. These unique creatures exhibit traits of both plants and animals: they can photosynthesize (produce their own food using sunlight), but they can also move around in search of food. Their ability to photosynthesize produces oxygen. As a result of this oxygen combining with the dissolved iron in the water and by other means, the organisms cause iron to separate from the watery solution in the form of a solid, thereby creating stable substrates (surfaces) for other organisms to inhabit. In other words, Euglena are ecosystem engineers. They work to improve the environment for themselves and, in doing so, make their surroundings more habitable for other organisms. This type of bioengineering (engineering using biological organisms) fostered the development of all life on Earth, since the production of oxygen led to the proliferation of organisms that depend on oxygen, . and over the course of billions of years, the stable iron-based substrates eventually contributed to the formation of landmasses out of what was once a planet covered by water. Species like Euglena manufactured the current configuration of air, water, and land that makes this planet so uniquely hospitable to life today.

In the Berkeley Pit, Euglena are doing similar work. They thrive in the heavy-metal laden waters of the lake and are removing the iron, zinc, and cadmium out of solution, storing it in their bodies, and rendering the metals biologically inactive. When they die, their bodies and the metals’ they contain are deposited in the sediments at the bottom of the lake. The chemistry of the Berkeley Pit is changing slowly but surely, and research is underway to encourage the population increase of Euglena and similar organisms to biologically treat the water before it spills into critical waterways. Since the discovery of Euglena , more than forty species of similar microorganisms have been discovered in the lake, several of them new to science. Many of these have found suitable habitat because of the pioneering work of Euglena , and they also serve to neutralize and repair the pit’s toxic water. Species like Euglena are fascinating from an evolutionary perspective because they exhibit traits that not only confer advantages to their own species, but also create conditions that enable other types of life to thrive.

 

 

1

In 1995 an extremophile, or organism that thrives in extreme environments, was discovered in the United States in a lake outside of Butte, Montana. The body of water where it lives, known as the Berkeley Pit, is a former open-pit copper mine that is slowly filling with groundwater that dissolves heavy metals like arsenic, cadmium, zinc, and aluminum from the mine’s 2,000-foot-deep surface; the dissolved metals mix with the water to form a toxic (poisonous) solution. The Berkeley Pit is the largest hazardous waste site targeted for cleanup in the United States. As 2.6 million gallons of groundwater seep into the pit every day, the toxic brew edges ever closer to spilling into the Clark Fork River, which makes its way to the Columbia River and out to the ocean, representing a massive-scale ecological threat to the fisheries and communities in these areas.

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.

AEver-increasing toxic liquid from the Berkeley Pit site is in danger of spilling into rivers that eventually flow into the ocean, threatening the ecology of nearby fisheries and communities.

BThe Clark Fork River, which is the closest river to the Berkeley Pit, empties into the ocean, causing millions of gallons of toxic liquid to spill into the ocean every day.

CThe activities of fisheries and communities near the Berkeley Pit create an increasing amount of toxic groundwater, which spills into nearby rivers and then into the ocean.

DThe Berkeley Pit represents a massive threat to the water quality of nearby rivers and to the fish that live in them.

 

2

In 1995 an extremophile, or organism that thrives in extreme environments, was discovered in the United States in a lake outside of Butte, Montana. The body of water where it lives, known as the Berkeley Pit, is a former open-pit copper mine that is slowly filling with groundwater that dissolves heavy metals like arsenic, cadmium, zinc, and aluminum from the mine’s 2,000-foot-deep surface; the dissolved metals mix with the water to form a toxic (poisonous) solution. The Berkeley Pit is the largest hazardous waste site targeted for cleanup in the United States. As 2.6 million gallons of groundwater seep into the pit every day, the toxic brew edges ever closer to spilling into the Clark Fork River, which makes its way to the Columbia River and out to the ocean, representing a massive-scale ecological threat to the fisheries and communities in these areas.

According to paragraph 1, the Berkeley Pit is a favorable habitat for extremophiles because

Ait is filling up slowly with groundwater

Bit is extremely deep

Cit contains a toxic solution of dissolved metals

Dit once contained large amounts of copper

 

3

Though the water in the pit is as acidic as lemon juice and considered inhospitable to life, a novel species has emerged and is slowly but surely changing the lake’s toxic brew to one more habitable. An analytic chemist studying the lake noticed a clump of green slime floating in the lake and brought a sample to Dr. Grant Mitman of Montana Tech. Mitman brought his colleagues Don and Andrea Stierle into the lab, and they identified the slime as a colony of Euglena mutabilis , a single-celled organism that forms algae-like mats. How Euglena came to grow in the Berkeley Pit is unknown, although some attribute its spread to a flock of 350 snow geese that landed (and subsequently died) in the lake several months prior to the discovery of the organism. The geese may have carried reproductive material of the Euglena in their feces (waste matter).

Which of the following can be inferred from paragraph 2 about the discovery of Euglena in the Berkeley Pit?

AIt had been predicted for years by researchers at Montana Tech.

BIt was originally thought to be algae.

CIt was disputed by scientists who argued that the green slime was a common organism typically found in the feces of geese.

DIt was a great surprise to scientists who until then did not believe that life could exist there.

 

4

Euglena are among the oldest organisms in the world, having survived since the time when conditions on Earth were not too dissimilar to those found in the Berkeley Pit- -ancient acidic oceans were full of heavy metals and other free- floating elements. These unique creatures exhibit traits of both plants and animals: they can photosynthesize (produce their own food using sunlight), but they can also move around in search of food. Their ability to photosynthesize produces oxygen. As a result of this oxygen combining with the dissolved iron in the water and by other means, the organisms cause iron to separate from the watery solution in the form of a solid, thereby creating stable substrates (surfaces) for other organisms to inhabit. In other words, Euglena are ecosystem engineers. They work to improve the environment for themselves and, in doing so, make their surroundings more habitable for other organisms. This type of bioengineering (engineering using biological organisms) fostered the development of all life on Earth, since the production of oxygen led to the proliferation of organisms that depend on oxygen, . and over the course of billions of years, the stable iron-based substrates eventually contributed to the formation of landmasses out of what was once a planet covered by water. Species like Euglena manufactured the current configuration of air, water, and land that makes this planet so uniquely hospitable to life today.

According to paragraph 3, in which TWO of the following ways have Euglena aided the development of life on Earth? To receive credit, you must select TWO answer choices.

ABy providing food for land-based animals

BBy producing oxygen

CBy helping to create large landmasses

DBy removing harmful elements from the air

 

5

Euglena are among the oldest organisms in the world, having survived since the time when conditions on Earth were not too dissimilar to those found in the Berkeley Pit- -ancient acidic oceans were full of heavy metals and other free- floating elements. These unique creatures exhibit traits of both plants and animals: they can photosynthesize (produce their own food using sunlight), but they can also move around in search of food. Their ability to photosynthesize produces oxygen. As a result of this oxygen combining with the dissolved iron in the water and by other means, the organisms cause iron to separate from the watery solution in the form of a solid, thereby creating stable substrates (surfaces) for other organisms to inhabit. In other words, Euglena are ecosystem engineers. They work to improve the environment for themselves and, in doing so, make their surroundings more habitable for other organisms. This type of bioengineering (engineering using biological organisms) fostered the development of all life on Earth, since the production of oxygen led to the proliferation of organisms that depend on oxygen, . and over the course of billions of years, the stable iron-based substrates eventually contributed to the formation of landmasses out of what was once a planet covered by water. Species like Euglena manufactured the current configuration of air, water, and land that makes this planet so uniquely hospitable to life today.

According to paragraph 3, all of the following are true about Euglena EXCEPT:

AThey build their own habitat from iron-based materials.

BThey thrived even when the oceans were too acidic for most organisms.

CThey can produce their own food from the Sun’s energy.

DThey are able to look for food in their environment.

 

6

Euglena are among the oldest organisms in the world, having survived since the time when conditions on Earth were not too dissimilar to those found in the Berkeley Pit- –ancient acidic oceans were full of heavy metals and other free- floating elements. These unique creatures exhibit traits of both plants and animals: they can photosynthesize (produce their own food using sunlight), but they can also move around in search of food. Their ability to photosynthesize produces oxygen. As a result of this oxygen combining with the dissolved iron in the water and by other means, the organisms cause iron to separate from the watery solution in the form of a solid, thereby creating stable substrates (surfaces) for other organisms to inhabit. In other words, Euglena are ecosystem engineers. They work to improve the environment for themselves and, in doing so, make their surroundings more habitable for other organisms. This type of bioengineering (engineering using biological organisms) fostered the development of all life on Earth, since the production of oxygen led to the proliferation of organisms that depend on oxygen, . and over the course of billions of years, the stable iron-based substrates eventually contributed to the formation of landmasses out of what was once a planet covered by water. Species like Euglena manufactured the current configuration of air, water, and land that makes this planet so uniquely hospitable to life today.

Why does the author provide the information that Euglena were present in Earth’s“ancient acidic oceans”?

ATo suggest one reason why scientists believed that the organisms they found in the Berkeley Pit were Euglena

BTo help explain why Euglena are able to live in the conditions of the Berkeley Pit

CTo compare the age of Euglena with that of other similar organisms

DTo indicate that organisms having traits of both animals and plants have existed since Earth’s beginning

 

7

In the Berkeley Pit, Euglena are doing similar work. They thrive in the heavy-metal laden waters of the lake and are removing the iron, zinc, and cadmium out of solution, storing it in their bodies, and rendering the metals biologically inactive. When they die, their bodies and the metals’ they contain are deposited in the sediments at the bottom of the lake. The chemistry of the Berkeley Pit is changing slowly but surely, and research is underway to encourage the population increase of Euglena and similar organisms to biologically treat the water before it spills into critical waterways. Since the discovery of Euglena , more than forty species of similar microorganisms have been discovered in the lake, several of them new to science. Many of these have found suitable habitat because of the pioneering work of Euglena , and they also serve to neutralize and repair the pit’s toxic water. Species like Euglena are fascinating from an evolutionary perspective because they exhibit traits that not only confer advantages to their own species, but also create conditions that enable other types of life to thrive.

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

Anearby

Bvery important

Ceasy to reach

Dnatural

 

8

In the Berkeley Pit, Euglena are doing similar work. They thrive in the heavy-metal laden waters of the lake and are removing the iron, zinc, and cadmium out of solution, storing it in their bodies, and rendering the metals biologically inactive. When they die, their bodies and the metals’ they contain are deposited in the sediments at the bottom of the lake. The chemistry of the Berkeley Pit is changing slowly but surely, and research is underway to encourage the population increase of Euglena and similar organisms to biologically treat the water before it spills into critical waterways. Since the discovery of Euglena , more than forty species of similar microorganisms have been discovered in the lake, several of them new to science. Many of these have found suitable habitat because of the pioneering work of Euglena , and they also serve to neutralize and repair the pit’s toxic water. Species like Euglena are fascinating from an evolutionary perspective because they exhibit traits that not only confer advantages to their own species, but also create conditions that enable other types of life to thrive.

It can be inferred from paragraph 4 that Euglena and similar organisms can “biologically treat” the water in the Berkeley Pit by

Arepairing the toxic sediment at the bottom of the lake

Bremoving excess microorganisms from the lake

Cadding beneficial chemicals to the water when they die

Dremoving metals from the water

 

9

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

We owe its discovery to the chance observations of a scientist.

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

10

In 1995, an extremophile- -an organism that lives in extreme environments- -was discovered in a lake in the United States.

ACopper mining at the site of the Berkeley Pit disturbed ancient microorganisms that had been thriving in the groundwater beneath Earth’s surface.

BBy engaging in a kind of bioengineering of their environment, Euglena and similar microorganisms contributed to the conditions that made it possible for life to develop on Earth.

CWhile Euglena seemed to be removing heavy metals from the lake, it is now thought that the metals are released back into the water after the organisms die.

DHow Euglena , a species of extremophile, came to the lake is unknown, but its existence in the toxic waters is helping to neutralize and repair those waters.

ESpecies like Euglena are especially interesting because, by creating an environment that gives their own species advantages, they also improve the environment for other species.

FScientists have introduced more than forty other species of similar microorganisms into the Berkeley Pit, but as yet they have been unable to find a species that can effectively clean the lake.

 

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