This set of Class 12 Biology Chapter 14 Multiple Choice Questions & Answers (MCQs) focuses on “Ecosystem” for NEET Preparation.
1. What is the missing level of the organization?
Tertiary consumer → Secondary consumer → ? → Primary producer.
a) Carnivore
b) Primary consumer
c) Decomposer
d) Secondary producer
View Answer
Explanation: The missing level of the organization is the primary consumer. These are the organisms that depend on primary producers for their energy requirements. For example cow, goat, deer, buffalo feeding on grass.
2. What is the missing level of the organization?
First trophic level → Secound trophic level → Third trophic level → ?
a) Fourth tropic level
b) Next tropic level
c) No tropic level
d) Last tropic level
View Answer
Explanation: The missing level of the organization is the fourth tropic level. This level includes ultimate or top carnivores. These are the organisms that feed on lower carnivores for food and nutrition. An example is a peacock feeding on a snake that eats a frog who is feeding on an insect.
3. What is the missing level of the organization?
Phytoplankton → Zooplankton → ? → Man
a) Lion
b) Fishes
c) Aquatic plants
d) Fungi
View Answer
Explanation: The missing level of the organization is the fishes. Fishes are the carnivores feeding on zooplankton. This cycle is observed in fresh as well as sea-water. These small fishes are either consumed by man or the large fishes.
4. What is the missing level of the organization?
Grass → Grasshopper → ? → Man
a) Lion
b) Elephant
c) Wolf
d) Birds
View Answer
Explanation: The missing level of the organization is the birds. These are the secondary consumer that is carnivores, belonging to the third trophic level.
5. What is the missing level of the organization?
Grass → Cow → Wolf → ?
a) Grasshopper
b) Goat
c) Lion
d) Zooplankton
View Answer
Explanation: The missing level of organization is the lion. The lion is an ultimate or top carnivore. It is a tertiary consumer belonging to the fourth trophic level.
6. The symbol given below each arrow indicates the loss of energy from an ecosystem. In what form is this energy lost?
a) Vapours
b) Heat
c) Oxygen
d) Fecal matter
View Answer
Explanation: During the flow of energy in an ecosystem, the energy is dissipated in the form of heat during several metabolic activities. Heat is a result of cell respiration, a form of energy that is not used in an ecosystem and released in an abiotic environment.
7. Which of the following phenomenon is responsible for the initiation of a food chain?
a) Decomposition
b) Respiration
c) Fixation
d) Photosynthesis
View Answer
Explanation: Photosynthesis is the phenomenon responsible for the initiation of a food chain. Photosynthesis is a process in which producers (green plants) in the presence of CO2, water, sunlight, and chlorophyll yield energy and oxygen is released in the form of gas.
8. Which of the following organisms contain the greatest amount of energy?
a) Heterotrophs
b) Decomposers
c) Autotrophs
d) Scavengers
View Answer
Explanation: The autotrophs (producers) contain the maximum amount of energy. Producers are organisms that make their own food with the help of energy obtained from chemicals or the sun, water, and air. They are also known as autotrophs.
9. What is the trophic level of a lion in a forest ecosystem?
a) T1
b) T3
c) T0
d) T4
View Answer
Explanation: A lion is an ultimate or a top-level carnivore. Lion being a tertiary consumer belongs to the fourth trophic level.
10. On what does the number of individuals in each trophic level depend on?
a) Number of individuals at upper trophic level
b) Number of individuals at top-most trophic level
c) Number of individuals at lower trophic level
d) Amount of sunlight reaching the Earth’s surface
View Answer
Explanation: The number of individuals in each trophic level depends on the number of individuals at present in the lower trophic level. Producers are always more in number than all the consumers. Tertiary consumers are present in the least number.
11. What happens when the food energy passes from herbivores to carnivores and to the next organism?
a) Amount of energy increases
b) Amount of energy decreases
c) Energy becomes zero
d) Energy remains unchanged
View Answer
Explanation: The movement of food energy from herbivores to carnivores and to the next organism leads to loss of some energy, i.e. the amount of energy decreases. The amount of energy transferred from organic matter in a food chain from one trophic level to another is 10 percent.
12. What is the energy stored at the consumer level called?
a) Primary energy
b) Tertiary energy
c) Secondary productivity
d) Net productivity
View Answer
Explanation: The rate of production of new organic matter by heterotrophic organisms (consumers) is called secondary productivity. The secondary producers feed on primary consumers to fulfill their energy requirements.
13. Who forms the new organic matter giving rise to secondary productivity?
a) Producer
b) Consumer
c) Scavenger
d) Decomposer
View Answer
Explanation: The rate of production of new organic matter by heterotrophic organisms (consumers) is called secondary productivity. The secondary producers feed on primary consumers to fulfill their energy requirements.
14. Which of the following is the driving force of an ecosystem?
a) Biomass
b) Consumer
c) Producer
d) Solar energy
View Answer
Explanation: Solar energy is said to be the driving force of an ecosystem. The solar energy is converted into usable form by plants with the help of photosynthesis.
15. Which of the following event occurs in an ecosystem?
a) Unidirectional movement of energy
b) Coupled process of cycling of energy and nutrients
c) Independent cycling of energy
d) Recycling of micro and micronutrients at the same speed
View Answer
Explanation: In an ecosystem, a unidirectional flow of energy occurs. The movement of energy from the higher trophic levels and its distribution and loss as heat to the lower trophic levels in the environment is unidirectional. It means the energy moves in one direction only that is from higher to the lower-most level.
Sanfoundry Global Education & Learning Series – Biology – Class 12.
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