June 2013 CSIR NET Life science Exam - Model Questions

1. According to the heterotroph hypothesis, which gas was added to the environment by the first heterotrophs?

• nitrogen
• oxygen
• carbon dioxide
• water vapor

2. Which human activity would most likely result in the addition of an organism to the endangered species list?

• cover cropping
• use of pollution controls
• use of erosion controls
• irrigation

3. A typical aquarium ecosystem consists of

• plants and gravel
• fish, water and snails
• fish, plants, and snails
• water and gravel

4. The first organism in most natural food chains is

• an herbivore
• a decomposer
• photosynthetic
• carnivorous

5. Which factor is not necessary for an ecosystem to be self-sustaining?

• a constant source of energy
• living systems that incorporate energy into organic molecules
• a cycling ofmaterial between organisms and their environment
• an equal number of producers and consumers

6. Which title is most appropriate for the diagram below?

• Energy Flow and Material Cycles in an Ecosystem
• Evolution in an Ecosystem
• Succession in an Ecosystem
• The Water Cycle in an Ecosystem

7. Which substances are represented by A and B in the diagram below?

• A represents oxygen and B represents carbon dioxide
• A represents carbohydrates and B represents carbon dioxide
• A represents nitrogen and B represents carbon dioxide
• A represents carbon dioxide and B represents oxygen

8. Which group in the chart below contains only abiotic factors?

Group A	Group B	Group C	Group D
Sunlight Green plants Rainfall Consumers Oxygen	Sunlight Climate Rainfall Minerals Gases	Sunlight Green plants Rainfall Producers Carbon dioxide	Sunlight Rainfall Consumers Producers Water

• A
• B
• C
• D

Answer
1. carbon dioxide
2. irrigation
3. fish, plants, and snails
4. photosynthetic
5. an equal number of producers and consumers
6. Energy Flow and Material Cycles in an Ecosystem
7. A represents oxygen and B represents carbon dioxide
8. B