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Chapter: 12th Botany : Competitive Examination Questions

Plant Ecology - Competitive Examination Questions

Botany : Competitive Examination Questions

UNIT IX - Plant Ecology


1. Plants which produce characteristic pneumatophores and show vivipary belong to

a) Halophytes

b) psammophytes

c) hydrophytes

d) mesophytes


2. Mycorrhizae are the example of

a) amensalism

b) antibiosis

c) mutualism

d) fungistatis


3. If ‘+’ sign is assigned to beneficial interaction, ‘-’ sign to detrimental and ‘0’ sign to neutral interaction, then the population interaction represented by ‘+’ ‘-’ refers to

a) mutualism

b) amensalism

c) commensalism

d) parasitism


4. Which of the following is correctly matched?

a) Aerenchyma - Opuntia

b) Age pyramid - Biome

c) Parthenium hysterophorus  - Threat to biodiversity

d) Stratification - Population


5. An association of individuals of different species living in the same habitat and having functional interactions is

a) Population

b) Ecological niche

c) Biotic community

d) Ecosystem


6. Roots play in significant role in absorption of water in

a) Wheat

b) Sunflower

c) Pistia

d) Pea


7. If we uncover half of the forest covering the earth, what crisis will be produced at most and the first?

a. Some species will be extinct

b. Population and ecological imbalance will rise up

c. Energy crisis will occur

d. Rest half forests will maintain this imbalance.


8. Most animals are tree dwellers in a

a) Tropical rain forest

b) Coniferous forest

c) Thorn woodland

d) Temperate deciduous fo


9. Cuscuta is an example of

a) Ectoparasitism

b) Brood parasitism

c) Predation

d) Endoparasitism


10. Large woody vines are more commonly found in

a) Alphine forests

b) Temperate forests

c) Mangroves

d) Tropical rain forests


11. Niche overlap indicates

a) Active co-operation between two species

b) Two different parasites on the same host

c) Sharing of one or more resources between the two species

d) Mutualism between two species


12. Which one of the following pairs is mismatched?

a) Savanna – Acacia trees

b) Prairie – Epiphytes

c) Tundra – Permafrost

d) Coniferous forest – Evergreen trees


13. Which ecosystem has the maximum biomass?

a) Grassland ecosystem

b) Pond ecosystem

c) Lake ecosystem

d) Forest ecosystem


14. Which of the following would appear as the pioneer organisms on bare rocks?

a) Mosses

b) Green algae

c) Lichens

d) Liverworts


15. In which of the following both pairs have correct combination?

a) Gaseous nutrient cycle Sulphur Sedimentary nutrient cycle : - Nitrogen and Carbon and Phosphorous

b) Gaseous nutrient cycle Sedimentary nutrient cycle : - Sulphur and Phosphorous Carbon and Nitrogen

c) Gaseous nutrient cycle Sedimentary nutrient cycle : - Carbon and  Nitrogen Sulphur and Phosphorous

d) Gaseous nutrient cycle Sedimentary nutrient cycle : - Carbon and Sulphur Nitrogen and Phosphorous


16. Secondary succession takes place on / in

a) newly created pond

b) newly cooled lava

c) bare rock

d) degraded forest


17. In an ecosystem the rate of production of organic matter during photosynthesis is termed as

a) Secondary productivity

b) net productivity

c) Net primary productivity

d) gross primary productivity


18. Natural reservoir of phosphorous is

a) rock

b) fossils

c) sea water

d) animal bones


19. Secondary productivity is rate of formation of new organic matter by

a) consumers

b) decomposers

c) producers

d) parasites


20. Which one of the following processes during decomposition is correctly described?

a) Catabolism – Last step in the decomposition under fully anaerobic condition

b) Leaching – Water soluble inorganic nutrient rise to the top layers of soil

c) Fragmentation – Carried out by organisms such as earthworms.

d) Humification – Leads to the accumulative of a dark coloured substance humus which undergoes microbial action in a very fast rate.


21. Which one of the following is not a functional unit of an ecosystem?

a) Energy flow

b) decomposition

c) Productivity

d) stratification


22. The upright pyramid of number is absent in

a) Pond

b) forest

c) lake

d) grassland


23. The rate of formation of new organic matter by rabbit in a grassland is called

a) net productivity

b) secondary productivity

c) net primary productivity

d) gross primary productivity


24. The second stage of hydrosere is occupied

by plants like

a) Azolla

b) Typha

c) Salix

d) Vallisneria


25. Which one of the following is a characteristic feature of cropland ecosystem?

a) Ecological succession

b) Absence of soil organisms

c) Least genetic diversity

d) Absence of weeds


26. Most animals that live in deep oceanic waters are

a) Detritivores

b) Primary consumers

c) Secondary consumers

d) Tertiary consumers


27. During ecological succession

a) The changes lead to a community that is in near equilibrium with the environment and is called pioneer community.

b) The gradual and predictable change in species composition occurs in a given area.

c) The establishment of a new biotic community is very fast in its primary phase.

d) The number and types of animals remain constant.


28. The mass of living material at a trophic level at a particular time is called

a) Standing crop

b) Gross primary productivity

c) Standing state

d) Net primary productivity


29.Match the following and select the correct option

Column I Column II

(I) Earthworm (i) pioneer species

(II) Succession (ii) Detritivore

Ecosystem service (iii) Natality (IV) Population growth (iv) Pollination


a) I : i, II: ii, III:  iii, IV:  iv

b) I : iv, II:  i, III:  iii, IV: ii

c) I : iii, II:  ii, III:  iv, IV:  i

d) I : ii, II:  i, III:  iv, IV:  iii


30. Given below is a simplified model of phosphorous cycling in a terrestrial ecosystem with four blanks (A – D. Identify the blanks.

 A B C D

a) Rock minerals - Detritus - Litter fall - Producers

b) Litter fall  - Producers - Rock minerals - Detritus

c) Detritus - Rock minerals - Producers - Litter fall

d) Producers - Litter fall - Rock minerals - Detritus


31. If 20 J of energy is trapped at producer level, then how much energy will be available to peacock as food in the following chain?

Plant → Mice → Snake → Peacock

a) 0.02 J

b) 0.002 J

c) 0.2 J

d) 0.0002 J


32. Given below is an imaginary pyramid of numbers. What could be one of the possibilities about certain organisms at some of the different levels ?

a) Level one PP is ‘pipal trees’ and the level SC is ‘sheep’.

b) Level PC is ‘rats’ and level SC is ‘cats’

c) Level PC is ‘insects’ and level SC is ‘small insectivorous birds’

d) Level PP is ‘phytoplanktons’ in sea and ‘whale’ on top level TC


33. Which one of the following statements for pyramid of energy is incorrect, whereas the remaining three are correct?

a) It is upright in shape

b) Its base is broad

c) It shows energy content of different trophic level organisms

d) It is inverted in shape


34. Which one of the following animals may occupy more than one trophic levels in the same ecosystem at the same time?

a) Goat

b) Frog

c) Sparrow

d) Lion


35. Both hydrarch and xerarch successions lead to

a) Highly dry conditions

b) Excessive wet conditions

c) Medium water conditions

d) Xeric conditions


36. Of the total incident solar radiation the proportion of PAR is

a) More than 80%

b) About 70%

c) About 60%

d) Less than 50%


37. The breakdown of detritus into smaller particles by earthworm is a process called

a) Mineralisation

b) Catabolism

c) Humification

d) Fragmentation


38. The biomass available for consumption by the herbivores and the decomposers is called

a) Gross primary productivity

b) Net primary productivity

c) Secondary productivity

d) Standing crop


39. 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


40. About 70% of the total global carbon is found in

a) Forests

b) Grasslands

c) Agro ecosystems

d) Oceans


41. Consider the following statements concerning food chains

i) Removal of 80% tigers from an area resulted in greatly increased growth of vegetation.

ii) Removal of most of the carnivores resulted in an increased population of deers.

iii) The length of food chains is generally limited to 3 – 4 trophic levels due to energy loss.

iv) The length of food chains may vary from 2 to 8 trophic levels.

Which two of the above statements are correct?

a) i and ii

b) ii and iii

c) iii and iv

d) i and iv


42. Which one of the following is not used for construction of ecological pyramids?

a) Dry weight

b) Number of individuals

c) Rate of energy flow

d) Fresh weight


43. The UN Conference of Parties on climate change in the year 2012 was held at

a. Lima

b. Warsaw

c. Durban

d. Doha.


44. Which of the following are most suitable indicators of SO2 pollution in the environment?

a. Algae

b. Fungi

c. Lichens

d. Conifers


45. Which of the following is not one of the prime health risks associated with greater UV radiations through the atmosphere due to depletion of stratospheric ozone?

a. Damage to eyes

b. Increased liver cancer

c. Increased skin cancer

. Reduced Immune system


46. A location with luxuriant growth of lichens on the trees indicates that the

a. trees are very healthy

b. trees are heavily infested

c. location is highly polluted

d. location is not polluted.


47. The ozone of atmosphere in which the ozone layer is present is called

a. ionosphere

b. mesosphere

c. stratosphere

d. troposphere


48. Which one of the following is a wrong statement?

a. Most of the forests have been lost in tropical areas.

b. Ozone in upper part of atmosphere is harmful to animals.

c. Greenhouse effect is a natural phenomenon.

d. Eutrophication is a natural phenomenon in freshwater bodies.


49. Good ozone is found in the

a. mesosphere


c. stratosphere

d. ionosphere


50. Chipko movement was launched for the protection of

a. forests

b. livestock




51. Identify the correctly matched pair.

a. Basal convention – Biodiversity conservation

b. Kyoto protocol -Climatic change

c. Montreal protocol -Global warming

d. Ramsar convention -Ground water pollution


52. Common indicator organism of water pollution is

a. Lemna pancicostata

b. Eichhornia crassipes

c. Escherichia coli

d. Entamoeba histolytica


53. Which country has the greatest contribution for the hole formation in ozone layer?

a. Russia

b. Japan

c. USA

d Germany


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12th Botany : Competitive Examination Questions : Plant Ecology - Competitive Examination Questions |

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