RC UPSC CSAT 2017 PRACTICE PASSAGE - ENVIRONMENT

Passage 

A species that exerts an influence out of proportion to its abundance in an ecosystem is called a keystone species. The keystone species may influence both the species richness of communities and the flow of energy and materials through ecosystems., The sea satr Pisaster ochraceus, which lives in rocky intertidal ecosystems on the Pacific coast of North America, is also an example of a keystone specie. Its preferred prey is the mussel Mytilus californianus In the absence of sea stars, these mussels crowd out other competitors in a broad belt of the intertidal zone. By consuming mussels, sea star creates bare spaces that are taken over by a variety of other species. 

A study at the University of Washington demonstrated the influence of Pisaster on species richness by removing sea stars from selected parts of the intertidal zone repeatedly over a period of five years. Two major changes occurred in the areas form which sea stars were removed. First, the lower edge of the mussel bed extended farther down into the intertidal zone, showing that sea stars are able to eliminate mussels completely where they are covered with water most of the time. Second, and more dramatically 28 species of animals and algae disappeared from the sea star removal zone. Eventually only Mytilus, the dominant competitor, occupied the entire substratum. Through its effect on competitive relationships, predation by Pisaster largely determines which species live in these rocky intertidal ecosystems. 

1. What is the crux of the passage?

(a) Sea star has a preferred prey.

(b) A preferred prey determines the survival of a keystone species.

(c) Keystone species ensures species diversity.

(d) Sea star is the only keystone species on the Pacific coast of North America.

2. With reference to the passage, consider the following statements:

1. Mussels are generally the dominant species in intertidal ecosystems.

2. The survival of sea stars is generally determined by the abundance of mussels.

Which of the statements given above is/are correct?

(a) 1 only

(b) 2 only

(c) Both 1 and 2

(d) Neither 1 nor 2 

3. Which of the following is/are implied by the passage?

1. Mussels are always hare competitors for sea stars.

2. Sea stars of the Pacific coast have reached the climax of their evolution.

3. Sea stars constitute an important component in the energy flow in intertidal ecosystem.

Which of the statements given above is/are correct?

(a) 1 and 2

(b) 2 only

(c) 1 and 3

(d) 3 only

4. Consider the following assumptions:

1. The food chains/food web in an ecosystem are influenced by keystone species.

2. The presence of keystone species is a specific characteristic of aquatic ecosystems.

3. If the keystone species is completely removed from an ecosystem, it with lead to the collapse of the ecosystem.

With reference to the passage, which of the above assumptions is/are valid?

(a) 1 only

(b) 2 and 3 only

(c) 1 and 3 only

(d) 1, 2 and 3

ANSWERS:

RC UPSC CSAT 2017 PRACTICE 01

A moral act must be our own act; must spring from our own will. If we act mechanically, there is no moral content in our act. Such action would be moral, if we think it proper to act like a machine and dos so. For, in doing so, we use our discrimination. We should bear in mind the distinction between acting mechanically and acting intentionally. It may be moral of a king to pardon a culprit. But the messenger carrying out the order of pardon plays only a mechanical part in the king’s moral act. But if the messenger were to carry out king’s order considering it to be his duty, his action would be a moral one. How can a man understand morality who does not use his own intelligence and power of thought, but lets himself be swept along like a log of wood by a current? Sometimes a man defies convention and acts on his own with a view to absolute good.

4. Which of the following statements best describe/describes the thought of the writer?

1. A moral act calls for using our discretion.

2. Man should react to a situation immediately.

3. Man must do his duty.

4. Man should be able to defy convention in order to be moral.

Select the correct answer from the codes given below:

(a) 1 only

(b) 1 and 3

(c) 2 and 3

(d) 1 and 4

5. Which of the following statements is the nearest definition of moral action, according to the writer?

(a) It is a mechanical action based on official orders from superiors.

(b) It is an action based on our sense of discretion.

(c) It is a clever action based on the clarity of purpose.

(d) It is a religious action based on understanding.

6. The passage contains a statement “lets himself be swept along like a log of wood by a current.” Among the following statements, which is/are nearest in meaning to this?

1. A person does not use his own reason.

2. He is susceptible to influence/pressure.

3. He cannot withstand difficulties/challenges.

4. He is like a log of wood

Select the correct answer using the codes given below:

(a) 1 only

(b) 1 and 2

(c) 2 and 3

(d) 1 and 4 

ANSWERS :

RC UPSC CSAT 2017 PRACTICE

Directions for the following 6 (six) items: 

Read each of the following two passages and answer to these items that follow. Your answers to items should be based on the passages only. 

Ecosystems provide people with a variety of goods and services; food, clean water, clean air, flood control, soil stabilization, pollination, climate regulation, spiritual fulfillment and aesthetic enjoyment, to name just a few. Most of these benefits either are irreplaceable or the technology necessary to replace them is prohibitively expensive. For example, potable fresh water can be provided by desalinating sea-water, but only at great cost. 

The rapidly expanding human their increased requirements of some of the goods and services, particularly food, fresh water, timber, fibre and fuel. These modifications have contributed substantia economic development. The benefits have not been equally distributed. Some people have actually been harmed by these changes. Moreover, short goods and services have come at the cost of the long efforts to increase the production of food and fibre have decreased the ecosystems to provide clean water, regulate flooding and support biodiversity.

1 . With reference to the passage, consider the following statements.

Expanding human population has an adverse effect on :

1. Spiritual fulfillment

2. Aesthetic enjoyment

3. Potable fresh water

4. Production of food and fibre

5. Biodiversity

Which of the statements given above are correct?

(a) 1, 2 and 3 only

(b) 2, 4 and 5 only

(c) 3 and 5 only

(d) 1, 2, 3, 4 and 5

2. The passage mentions that “some people have actually been harmed by these changes”. What does it imply?

1. The rapid expansion of population has adversely affected some people.

2. Sufficient efforts have not been made to increase the production of food and fibre.

3. In the short term some people may be harmed, but in the long term everyone will benefit from modifications in the Earth’s ecosystems.

Which of the statement given above is/are correct?

(a) 1 only

(b) 2

(c) 1 and 3

(d) None of the statements given above

3. With reference to the passage, consider the following statements:

1. It is imperative to modify the Earth’s ecosystems for the well being of mankind.

2. Technology can never replace all the goods and services provided by ecosystems.

Which of the statements given above is/are correct?

(a) 1 Only

(b) 2 Only

(c) Both 1 and 2

(d) Neither 1 nor 2 

Answers :