CBSE Class 12 Biology Ecosystem Worksheet Set A

Read and download free pdf of CBSE Class 12 Biology Ecosystem Worksheet Set A. Students and teachers of Class 12 Biology can get free printable Worksheets for Class 12 Biology in PDF format prepared as per the latest syllabus and examination pattern in your schools. Standard 12 students should practice questions and answers given here for Biology in Grade 12 which will help them to improve your knowledge of all important chapters and its topics. Students should also download free pdf of Class 12 Biology Worksheets prepared by school teachers as per the latest NCERT, CBSE, KVS books and syllabus issued this academic year and solve important problems provided here with solutions on daily basis to get more score in school exams and tests

Ecosystem Class 12 Biology Worksheet Pdf

Class 12 Biology students should refer to the following printable worksheet in Pdf for Ecosystem in standard 12. This test paper with questions and answers for Grade 12 Biology will be very useful for exams and help you to score good marks

Class 12 Biology Worksheet for Ecosystem

1 What does the base tier of the ecological pyramid represent?

2 In the North East region of India, during the process of jhum cultivation, forests are cleared by burning and left for regrowth after a year of cultivation. How would you explain the regrowth of forest in ecological term?

3 Climax stage is achieved quickly in secondary succession as compared to primary succession. Why?

4 Why are oceans least productive?

5 Organisms at a higher trophic level have less energy available. Comment.

6 What are the shortcomings of ecological pyramids in the study of ecosystem?

7 How do you distinguish between humification and mineralisation?

8 List three parameters used for constructing ecological pyramids. Describe any one instance where the pyramid may look inverted.

9 Differentiate between a detritivore and a decomposer giving an example of each.

10 Construct an ideal pyramid of energy when 1,00,000 joules of sunlight is available. Label all its trophic levels.

11 Construct a pyramid of biomass starting with phytoplanktons. Label 3 trophic levels. Is the pyramid upright or inverted? Why?

12 Explain with the help of two examples how the pyramid of number and the pyramid of biomass can look inverted.

13 Justify the given statements:

a) Energy flow in an ecosystem is unidirectional

b) Secondary succession is faster than primary succession

14 What will happen to an ecosystem if:

a) All producers are removed

b) All organisms of herbivore level are eliminated

c) All top carnivore population is removed 


Important Questions for NCERT Class 12 Biology Ecosystem

 

Question. The rate of biomass production is called productivity.
It may be primary or secondary productivity. Primary productivity does not depends on
(a) Plants species inhabitating a particular area
(b) Predation
(c) Environmental factors
(d) Photosynthetic capacity

Answer : B

Question. Which among the following is not considered as an ecological service?
(a) Generation of fertile soil
(b) Wild life habitat formation
(c) Products of antibiotics
(d) Crop pollination

Answer : C

Question. Which among the following factors are most important climatic factors that regulate decomposition through their effects on the activities of soil microbes
(a) Temp & soil moisture
(b) Temp and pH of soil
(c) Temp and oxygen
(d) pH of soil and oxygen

Answer : A

Question. Decomposition is one of the important functional aspect of ecosystem. Which of the following statement is not correct for decomposition ?
(a) Warm and moist environment favours decomposition
(b) Nitrogen and sugar component favours decomposition
(c) Low temperature and anaerobiosis favours decomposition
(d) Decomposition is largely an oxygen requiring process

Answer : C

Question. Robert Constanza and his colleagues have put price tags on natures life support services with refrence to this which of the following is not true?
(a) Fundamental ecosystem services = $ 33 trillions
(b) Soil formation = $ 16.5 trillions
(c) Nutrient cycling = less than $ 3.3 trillions
(d) Climate regulation = $ 5 trillions

Answer : D

Question. The annual net primary productivity of the whole biosphere is approximately
(a) 170 billion tons
(b) 50 billion tons
(c) 55 billion tons
(d) 710 billion tons

Answer : A

Question. By digestion and pulverisation detritus get fragmented. This fragmentation step of decomposition helps in
(a) Increasing porocity of detritus
(b) Increasing surface area of detritus
(c) Increasing rate of sedimentation
(d) All of these

Answer : B

Ques. Pyramid of numbers deals with number of
(a) species in an area
(b) individuals in a community
(c) individuals in a trophic level
(d) subspecies in a community. 

Answer: C

Ques. Pyramid of numbers in a pond ecosystem is
(a) irregular
(b) inverted
(c) upright
(d) spindle shaped.

Answer: C

Ques. Which of the following would appear as the pioneer organisms on bare rocks?
(a) Mosses
(b) Green algae
(c) Lichens
(d) Liverworts

Answer: C

Ques. During ecological succession
(a) the numbers and types of animals remain constant
(b) the changes lead to a community that is in near equilibrium with the environment and is called pioneer community
(c) the gradual and predictable change in species composition occurs in a given area
(d) the establishment of a new biotic community is very fast in its primary phase. 

Answer: C

Ques. Secondary succession takes place on/in
(a) newly created pond
(b) newly cooled lava
(c) bare rock
(d) degraded forest. 

Answer: D

Ques. The second stage of hydrosere is occupied by plants like
(a) Azolla
(b) Typha
(c) Salix
(d) Vallisneria.

Answer: D

Ques. Which one of the following statements is correct for secondary succession?
(a) It begins on a bare rock.
(b) It occurs on a deforested site.
(c) It follows primary succession.
(d) It is similar to primary succession except that it has a relatively fast pace. 

Answer: B

Ques. Both hydrarch and xerarch successions lead to
(a) medium water conditions
(b) xeric conditions
(c) highly dry conditions
(d) excessive wet conditions. 

Answer: A

Ques. The correct sequence of plants in a hydrosere is
(a) Volvox → Hydrilla → Pistia → Scirpus → Lantana → Oak
(b) Pistia → Volvox → Scirpus → Hydrilla → Oak → Lantana
(c) Oak → Lantana → Volvox → Hydrilla → Pistia → Scirpus
(d) Oak → Lantana → Scirpus → Pistia → Hydrilla → Volvox. 

Answer: A

Ques. An ecosystem which can be easily damaged but can recover after some time if damaging effect stops will be having
(a) low stability and high resilience
(b) high stability and low resilience
(c) low stability and low resilience
(d) high stability and high resilience. 

Answer: A

Ques. The primary succession refers to the development of communities on a
(a) forest clearing after devastating fire
(b) newly-exposed habitat with no record of earlier vegetation
(c) freshly cleared crop field
(d) pond, freshly filled with water after a dry phase. 

Answer: B

Ques. Natural reservoir of phosphorus is
(a) rock
(b) fossils
(c) sea water
(d) animal bones.

Answer: A

Ques. Which one of the following is not a gaseous biogeochemical cycle in ecosystem?
(a) Sulphur cycle
(b) Phosphorus cycle
(c) Nitrogen cycle
(d) Carbon cycle

Answer: B

Ques. About 70% of total global carbon is found in
(a) oceans
(b) forests
(c) grasslands
(d) agroecosystems.

Answer: A

Ques. Which of the following pairs is a sedimentary type of biogeochemical cycle?
(a) Phosphorus and nitrogen
(b) Phosphorus and sulphur
(c) Oxygen and nitrogen
(d) Phosphorus and carbon dioxide 

Answer: B

Ques. Match the following and select the correct option.
A. Earthworm (i) Pioneer species
B. Succession (ii) Detritivore
C. Ecosystem service (iii) Natality
D. Population growth (iv) Pollination
      A   B    C    D
(a) (i) (ii)  (iii) (iv)
(b) (iv) (i) (iii) (ii)
(c) (iii) (ii) (iv) (i)
(d) (ii) (i) (iv) (iii

Answer: D


Please click the link below to download full pdf file for CBSE Class 12 Biology Ecosystem (1).

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