Students get through the TN Board 12th Bio Botany Important Questions Chapter 7 Ecosystem which is useful for their exam preparation.

TN State Board 12th Bio Botany Important Questions Chapter 7 Ecosystem

Very short answer questions

Question 1.
Define ecosystem.
Answer:
The ecosystem is defined as the structural and functional unit of ecology.

Question 2.
Mention the major components of the ecosystem.
Answer:

  1. Abiotic components – Nonliving
  2. Biotic components – Living

Question 3.
What is Photosynthetically Active Radiance (PAR)?
Answer:
Photosynthetically Active Radiation is the amount of light available for the photosynthesis of plants.
This is the range between 400-700 nm wavelength.

TN Board 12th Bio Botany Important Questions Chapter 7 Ecosystem

Question 4.
Give any two functions of the ecosystem.
Answer:

  1. Energy cycling
  2. Cycling of materials between the living and non-living components.

Question 5.
Define productivity.
Answer:
Productivity is defined as the rate of biomass production per unit area in a unit of time.

Question 6.
Define community productivity.
Answer:
Community productivity is defined as the rate of net synthesis of organic matter by a group of plants per unit area in a unit of time.

Question 7.
What is meant by the food web?
Answer:
Food web is a web like arrangement in which the interlocking pattern of a number of food chain exist.

Question 8.
Define ecological pyramid.
Answer:
An ecological pyramid is defined as the graphic representation of trophic structure and function at successive trophic levels of an ecosystem.

TN Board 12th Bio Botany Important Questions Chapter 7 Ecosystem

Question 9.
Explain Humification.
Answer:
Humification is a process by which the dark-colored amorphous substance (humus) is formed from simplified detritus.

Question 10.
Mention the types of freshwater ecosystems.
Answer:

  1. Lotic – running water bodies.
  2. Lentic – Standing water bodies.

Question 11.
Mention any two phytoplankton in the pond ecosystem.
Answer:

  1. Oscillatoria
  2. Anabaena

Question 12.
The photosynthesis is more in a limnetic zone of the pond. Why?
Answer:
The photosynthesis is more in the limnetic zone of a pond, because of the greater penetration of i sunlight.

Question 13.
Mention any two cultural services of the ecosystem.
Answer:

  1. Education and inspiration.
  2. Spiritual and religious values.

Question 14.
List out two factors, which affect the ecosystem.
Answer:

  1. Deforestation and over-grazing.
  2. Habitat destruction.

TN Board 12th Bio Botany Important Questions Chapter 7 Ecosystem

Question 15.
What is ecosystem resilience?
Answer:
Ecosystem resilience is the ability of the ecosystem to resist damage caused by disturbances from flood, fire, infection, predation drought, etc., and recover quickly.

Short answer questions

Question 1.
Explain briefly about autotrophic succession.
Answer:
Autotrophic succession is the condition, in which the green plants are dominant during the early stage of succession. If the soil is rich in inorganic substances, this succession occurs. As the green plants dominate at the beginning of this succession, an increase in organic matter in the ecosystem results. The energy flow subsequently increases in the ecosystem.

Question 2.
Describe the different levels of consumers in the pond ecosystem.
Answer:
In the pond ecosystem, the primary consumers include zooplanktons like Paramoecium, Daphnia, etc., The bottom-dwelling benthic organisms include mollusks and annelids. The water beetle and frogs form the secondary consumers. Ducks and cranes constitute the tertiary consumers (carnivores). Large fish, hawk man, etc., are the top carnivores in the pond ecosystem.

Question 3.
Distinguish between lotic and lentic ecosystems.
Answer:

Lotic Ecosystem Lentic Ecosystem
It is running water ecosystem. It is standing water body.
It includes river spring and stream. It includes ponds and lakes.
In times of drought shallow systems will dry up and many organism will die. During periods of drought these systems will often last longer than its counterpart.

TN Board 12th Bio Botany Important Questions Chapter 7 Ecosystem

Question 4.
Explain ten percent law.
Answer:
Lindeman in 1942 proposed a ten percent law. This law states that when the energy is transferred from one trophic level to another trophic level, only 10% of food energy is stored at every level. The rest of food energy (90%) is lost through respiration, decomposition, and in the form of heat. Hence this law is called the ten percent law.

Question 5.
Distinguish between macro consumers and micro consumers.
Answer:

Macro consumers Micro consumers
Macro consumers refer to herbivores, carnivores, omnivores. Micro consumer are decomposers.
They are primary secondary and tertiary consumers Organisms that decompose dead plants and animals to release organic and inorganic nutrients, which are reused by plants.
Eg: Rabbit, hawk, lion etc. Eg: Bacteria, Actinomycetes, Fungi etc.

Question 6.
Write a diagrammatic representation of energy flow.
Answer:
TN Board 12th Bio Botany Important Questions Chapter 7 Ecosystem 1

Question 7.
Write down the significance of the food web.
Answer:

  1. The Food web is made to explain species interaction (Direct interaction).
  2. It is also helpful to illustrate indirect interaction among different species.
  3. It can be used to study the community structure of an ecosystem.
  4. Food web can be used to reveal different patterns of energy flow in terrestrial and aquatic ecosystems.

TN Board 12th Bio Botany Important Questions Chapter 7 Ecosystem

Long answer questions

Question 1.
Write in detail about the concept of trophic level in an ecosystem.
Answer:
The position of an organism in a food chain is referred as a trophic level. The number of steps in a food chair is equal to the number of trophic levels in an ecosystem.
The first trophic level (T1) is occupied by green plants and they are called producers.
The primary consumers are in the second trophic level (T2) and they utilize the energy produced by the producers. They are called herbivores. The herbivores are eaten by carnivores and they occupy the third trophic level (T3). They are also called secondary consumers or primary carnivores. The fourth trophic level (T4) is occupied by carnivores which eat on primary carnivores. They are otherwise known as tertiary consumers or secondary carnivores. The omnivores eat ‘ both plants and animals. They may occupy more than one trophic level in the food chain.
TN Board 12th Bio Botany Important Questions Chapter 7 Ecosystem 2

Question 2.
Explain food web with suitable diagram.
Answer:
Food web is a web like arrangement in which the interlocking pattern of a number of food chain can exist. It is the basic unit of an ecosystem, to maintain its stability in nature. It is otherwise known as homeostasis.
Eg: In a grazing food chain of a grass land, a mouse may also eat food grains in the absence of rabbit in the ecosystem. The mouse in turn may be eaten directly by a hawk or by a snake and a snake may directly be eaten by hawk.
Therefore, the interlocking pattern of the food chain is the food web. The species of an ecosystem may remain balanced to. each other by some sort of natural check.
TN Board 12th Bio Botany Important Questions Chapter 7 Ecosystem 3

TN Board 12th Bio Botany Important Questions Chapter 7 Ecosystem

Question 3.
Draw the diagrammatic representation of pyramids of biomass in different types of ecosystems.
Answer:
TN Board 12th Bio Botany Important Questions Chapter 7 Ecosystem 4

Question 4.
How do anthropogenic activities affect ecosystem services?
Answer:
Human being and their activities make the destruction of the ecosystem. We all exploit nature than that of our needs. The ecosystem is exploited in order to meet rapidly growing demands for food, freshwater, medicine, timber, fiber and fuel. The deterioration, caused by present-day human activities changed the ecosystem rapidly and extensively than in any comparable period of time in human history.
The followings are factors caused by human activities which disturb an ecosystem.

  1. The destruction of habitats.
  2. Deforestation and over-grazing.
  3. Erosion of soils.
  4. Introduction of alien species.
  5. Overharvesting of plant material.
  6. Pollution of land, water, and air.
  7. Runoff pesticides, fertilizers, and animal waste.

TN Board 12th Bio Botany Important Questions Chapter 7 Ecosystem

Question 5.
Write down the strategies of ecosystem management.
Answer:
The strategies of ecosystem management are as follows.

  1. The biodiversity of ecosystems ought to be maintained.
  2. Flagship species are the species that indicate the health of the ecosystem. This helps in indicating the damaged ecosystem.
  3. It is helpful to recognize the inc it Vilify of ecosystem change and plans accordingly.
  4. The sustainability of the ecosystem through sustainable development can be achieved by a strategy of ecosystem management.
  5. The ecosystems, which are in need of rehabilitation can be identified by this strategy.
  6. The management strategy involves government agencies, the local population, communities, and NGOs.
  7. To build the capacity of local institutions and communities in order to create responsibility for the long-term implementation of ecosystem management activities.

Choose the correct answers.

1. Match the following.
TN Board 12th Bio Botany Important Questions Chapter 7 Ecosystem 5
(a) (p)-(iv); (q)-(iii); (r)-(ii); (s)-(i)
(b) (p)-(iv); (q)-(iii); (r)-(i); (s)-(ii)
(c) (p)-(ii); (q)-(i); (r)-(iv); (s)-(iii)
(d) (p)-(iii); (q)-(iv); (r)-(ii); (s)-(ii)
Answer:
(b) (p)-(iv); (q)-(iii); (r)-(i); (s)-(ii)

2. Match the following.
TN Board 12th Bio Botany Important Questions Chapter 7 Ecosystem 6
(a) (p)-(iv); (q)-(iii); (r)-(u); (s)-(i)
(b) (p)-(iv); (q)-(iii); (r)-(i); (s)-(ii)
(c) (p)-(ii); (q)-(i); (r)-(iv); (s)-(iii)
(d) (p)-(iii); (q)-(iv); (r)-(i); (s)-(ii)
Answer:
(a) (p)-(iv); (q)-(iii); (r)-(u); (s)-(i)

3. Match the following.
TN Board 12th Bio Botany Important Questions Chapter 7 Ecosystem 7
(a) (p)-(iv); (q)-(iii); (r)-(ii); (s)-(i)
(b) (p)-(iv); (q)-(iii); (r)-(i); (s)-(ii)
(c) (p)-(iii); (q)-(iv); (r)-(i); (s)-(ii)
(d) (p)-(ii); (q)-(i); (r)-(iv); (s)-(iii)
Answer:
(c) (p)-(iii); (q)-(iv); (r)-(i); (s)-(ii)

TN Board 12th Bio Botany Important Questions Chapter 7 Ecosystem

4. Match the following.
TN Board 12th Bio Botany Important Questions Chapter 7 Ecosystem 8
(a) (p)-(iv); (q)-(iii); (r)-(ii); (s)-(i)
(b) (p)-(ii); (q)-(i); (r)-(iv); (s)-(iii)
(c) (p)-(iv); (q)-(iii); (r)-(i); (s)-(ii)
(d) (p)-(iii); (q)-(i): (r)-(iv); (s)-(ii)
Answer:
(d) (p)-(iii); (q)-(i): (r)-(iv); (s)-(ii)

5. Match the following.
TN Board 12th Bio Botany Important Questions Chapter 7 Ecosystem 9
(a) (p)-(ii); (q)-(i); (r)-(iv); (s)-(iii)
(b) (p)-(iv); (q)-(iii); (r)-(ii); (s)-(i)
(c) (p)-(iv); (q)-(iii); (r)-(i); (s)-(ii)
(d) (p)-(iii); (q)-(iv); (r)-(ii); (s)-(i)
Answer:
(a) (p)-(ii); (q)-(i); (r)-(iv); (s)-(iii)

6. Which of the following is not a biotic factor?
(a) Bacteria
(b) Fungi
(c) Carbohydrate
(d) Algai
Answer:
(c) Carbohydrate

7. Which of the following is an omnivore?
(a) Eagle
(b) Crow
(c) Rabbit
(d) Hawk
Answer:
(b) Crow

8. The movement of decomposed water-soluble organic and inorganic compounds from the surface to the lower layer of soil is called:
(a) Eluvation
(b) Filtration
(c) Sublimation
(d) Diffusion
Answer:
(a) Eluvation

TN Board 12th Bio Botany Important Questions Chapter 7 Ecosystem

9. Gaseous cycle in the atmosphere includes:
(a) Ammonia, oxygen and methane cycle
(b) Oxygen, nitrogen and ammonia cycle
(c) Oxygen, carbon, and nitrogen cycle
(d) Carbon dioxide, nitrogen, and methane cycle
Answer:
(c) Oxygen, carbon, and nitrogen cycle

10. Identify the regulating service of the ecosystem:
(a) Nutrient cycle
(b) Erosion
(c) Education value
(d) Medicines
Answer:
(b) Erosion

11. Choose the odd man out:
(a) Vernadsky
(b) Karl Mobius
(c) Watson
(d) Friederichs
Answer:
(c) Watson

TN Board 12th Bio Botany Important Questions Chapter 7 Ecosystem

12. Find out the odd one out:
(a) Mouse
(b) Deer
(c) Elephant
(d) Tiger
Answer:
(d) Tiger

13. Indicate the odd one out:
(a) Fragmentation
(b) Infiltration
(c) Catabolism
(d) Humification
Answer:
(b) Infiltration

14. Choose the odd one out:
(a) Forest
(b) Pond
(c) Maize field
(d) Lentic
Answer:
(c) Maize field

15. Identify the odd one out:
(a) Water cycling
(b) Seed dispersal
(c) Pest regulation
(d) Water purification
Answer:
(a) Water cycling

TN Board 12th Bio Botany Important Questions Chapter 7 Ecosystem

16. Which of the following is a correct pair?
TN Board 12th Bio Botany Important Questions Chapter 7 Ecosystem 10
Answer:
(c)

17. Find out the incorrect pair.
TN Board 12th Bio Botany Important Questions Chapter 7 Ecosystem 11
Answer:
(c)

18. Choose the correct pair.
TN Board 12th Bio Botany Important Questions Chapter 7 Ecosystem 12
Answer:
(b)

19. Identify the incorrect pair.
TN Board 12th Bio Botany Important Questions Chapter 7 Ecosystem 13
Answer:
(d)

20. Which of the following is the correct pair?
TN Board 12th Bio Botany Important Questions Chapter 7 Ecosystem 14
TN Board 12th Bio Botany Important Questions Chapter 7 Ecosystem 15
Answer:
(c)

TN Board 12th Bio Botany Important Questions Chapter 7 Ecosystem

21. Assertion: |n m0st ecosystems, green plants are autotrophs.
Reason: They have chlorophyll, which enables them to produce carbo-hydrate from simple inorganic components.
(a) Assertion and Reason are correct, Reason is the correct explanation of Assertion.
(b) Assertion and Reason are correct, Reason is not the correct explanation of Assertion.
(c) Assertion is false. The reason is true.
(d) Assertion and Reason are false.
Answer:
(a) Assertion and Reason are correct, Reason is the correct explanation of Assertion.

22. Assertion: The product of starch is formed during photosynthesis by the combination of reactants such as chlorophyll, H2O and carbon dioxide.
Reason: The energy stored in starch is obtained from the external source (light energy from sun)
(a) Assertion and Reason are correct, Reason is the correct explanation of Assertion.
(b) Assertion and Reason are correct, Reason is not the correct explanation of Assertion.
(c) Assertion is false, Reason is true.
(d) Assertion and Reason are false.
Answer:
(b) Assertion and Reason are correct, Reason is not the correct explanation of Assertion.

23. Assertion: In a forest ecosystem, the pyramid of numbers is somewhat different in shape.
Reason: The pyramid of numbers in the forest ecosystem looks spindle-shaped.
(a) Assertion and Reason are correct, Reason is the correct explanation of Assertion.
(b) Assertion and Reason are correct, Reason is hot the correct explanation of Assertion.
(c) Assertion is false, Reason is true.
(d) Assertion and Reason are false.
Answer:
(b) Assertion and Reason are correct, Reason is hot the correct explanation of Assertion.

TN Board 12th Bio Botany Important Questions Chapter 7 Ecosystem

24. Assertion: Seagrasses and mangroves of Estuarine and coastal ecosystems are called as blue carbon ecosystems.
Reason: They are more efficient in carbon sequestration.
(a) Assertion and Reason are correct, Reason is the correct explanation of Assertion.
(b) Assertion and Reason are correct, Reason is not the correct explanation of Assertion.
(c) Assertion is false, Reason is true.
(d) Assertion and Reason are false.
Answer:
(a) Assertion and Reason are correct, Reason is the correct explanation of Assertion.

25. Assertion: By 2025, at least 90% of the world’s population is projected to face water scarcity.
Reason: By 2025, 70% of forest cover will be destroyed.
(a) Assertion and Reason are correct, Reason is the correct explanation of Assertion.
(b) Assertion and Reason are correct, Reason is not the correct explanation of Assertion.
(c) Assertion is false, Reason is true.
(d) Assertion and Reason are false.
Answer:
(d) Assertion and Reason are false.

26. Which of the following statement is correct?
(a) Cultural services of the ecosystem include Ecotourism.
(b) Cultural services of the ecosystem include water purification.
(c) Cultural services of the ecosystem include water cycling.
(d) None of the above.
Answer:
(a) Cultural services of the ecosystem include Ecotourism.

TN Board 12th Bio Botany Important Questions Chapter 7 Ecosystem

27. Choose the incorrect statement:
(a) Mangrove ecosystem offers habitat for aquatic plants and animals.
(b) Mangrove ecosystem acts as a nursery for aquatic animals.
(c) It helps salt spray from waves.
(d) It provides medicine, fuelwood, and timber.
Answer:
(c) It helps salt spray from waves.

28. Find out the correct statement.
(a) The pyramid of energy is always spindle-shaped.
(b) The Pyramid of energy is always upright
(c) The pyramid of numbers in the forest ecosystems is always inverted.
(d) None of the above.
Answer:
(b) The Pyramid of energy is always upright

29. Indicate the incorrect statement.
(a) Ten-point law was proposed by Lindeman.
(b) The concept of ecological pyramids was introduced by Charles Elton.
(c) The ecosystem was defined by Odum
(d) All the above statements are not correct.
Answer:
(d) All the above statements are not correct.

TN Board 12th Bio Botany Important Questions Chapter 7 Ecosystem

30. Indicate the correct statement.
(a) All the primary producers are autotrophs.
(b) All the consumer are carnivores
(c) All the herbivores are only grass eaters.
(d) None of the above.
Answer:
(a) All the primary producers are autotrophs.