Download Junior Inter Botony Questions English Medium

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Junior Inter Botany
Plant ecology
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2 Marks Questions
1.
Climax stage is achieved quickly in secondary succession as compared to
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primary succession. Why?
A: Secondary succession starts in an area where living organisms already existed.
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Some soil or sediment is already present in this area. Whereas primary succession
starts on a bare rock, newly created pond or reservoir or cooled lava where it takes
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many years for formation of fertile soil. Hence establishment of communities and
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climax stage are quickly achieved in secondary succession as compared to
primary succession.
2.
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Give any two examples of xerarch succession.
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A: Bare rock, newly cooled lava, newly created pond or reservoir.
3.
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Define heliophytes and sciophytes. Name a plant from your locality that is
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either heliophyte or sciophyte.
A: ★ Plants that grow in direct sunlight are heliophytes.
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e.g.: Rose, Jasmine
★ Plants that grow in shady places are called sciophytes.
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e.g.: Pothos, ferns.
4.
Define population and community.
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A: Population: A group of similar individuals belonging to the same species found
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in an area.
Community: An assemblage of all populations belonging to different species in
an area.
5.
Define communities. Who classified plant communities into hydrophytes,
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mesophytes and xerophytes?
A: Communities are assemblages of different populations belonging to different
species living in an area. Eugen Warming classified plant communities into
hydrophytes, mesophytes and xerophytes.
R-11-1-15
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6.
Hydrophytes show reduced xylem. Why?
A: As the epidermis in hydrophytes is composed of thin walled cells and absorbs
water there is no need for xylem in hydrophytes. Hence xerophytes show
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reduced xylem.
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4 Marks Questions
7.
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Briefly discuss the different kinds of hydrophytes with examples.
A: Plants that grow in water or in very wet places are called hydrophytes.
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Types of hydrophytes:
★ Free floating hydrophytes: They do not have contact with the soil and float
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freely on the water. e.g.: Pistia
★ Rooted hydrophytes with floating leaves: These plants have roots and long
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petiolated floating leaves. e.g.: Nymphaea, Victoria regia.
★ Submerged suspended hydrophytes:
These plants are submerged and
suspended in the water but not rooted. e.g.: Hydrilla
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★ Submerged rooted hydrophytes:
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These plants are rooted and completely
submerged in water. e.g.: Vallisnaria
★ Amphibious plants: These plants are partly submerged in water and partly in
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air. e.g.: Saggitaria, Typha
Enumerate the morphological adaptations of xerophytes.
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A: The xerophytes show following morphological adaptations to grow in water
deficit conditions and minimize water loss:
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★ They have very well developed root system to absorb water from deep layers
of soil.
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★ The roots are extensively branched.
★ Root hair and root caps are well developed.
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★ In some plants roots may store water and swell up.
e.g.: Asparagus
★ Stems are stunted, woody, hard and covered with thick bark.
★ Some stems show hairy or waxy coating.
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★ In some plants the stems may store water and photosynthesise.
e.g.: Opuntia.
★ Leaves are reduced to scales or spines.
★ In some plants the leaves are succulent and store water. e.g.: Aloe.
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9.
Define ecosystem / ecological services. Explain in brief with regard to
pollination.
A: The processes by which the environment produces resources like clean water,
oxygen, timber, habitat for fisheries, pollination of native and agricultural plants
etc., are considered as ecosystem services or ecological services.
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Pollination as an ecological service:
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★ Pollination is the process of transfer of pollen grains from the stamens to the
stigma of the flowers.
★ It is very important to produce fruits and seeds in our crops.
★ Insects are the important agents of pollination in many flowering plants.
★ Nearly one lakh invertebrates and one thousand species of vertebrates are
found to help in pollination of many plant species.
★ But due to destruction of habitats and over use of pesticides in agriculture
many pollinator species are becoming extinct.
★ According to US Fish and Wildlife Service list nearly 50 pollinator species
are endangered.
★ The wild honey bee population is reduced to 25%.
★ This results in reduction in crop yields, increase in cost of fruits and
vegetables and imbalance in ecological systems.
★ Measures like planting native flower gardens, reducing pesticides etc., help
in protecting pollinators.
10. Write about the measures to be taken to sustain ecological functions.
A: Measures to sustain ecological functions:
★ Products produced by using less water and causing less environmental
damage should be used.
★ Organic food produced from natural methods which do not use chemical
pesticides and fertilizers should be encourages.
★ Over consumption of goods should be reduced.
★ Production of wastes should be minimized.
★ Renewable energy resources should be used.
★ Using public transport like buses and autos, walking and cycling not only
reduces pollution but also provides health benefits.
★ Community gardens and tree plantation programmes should be a part of
everyone's regular activities.
★ Native species should be protected to provide habitat for wildlife.
Writer: P.Uma Amareswari
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