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Plant Ecology - Ecological Adaptations, Succession and Ecological Services

Questions - Answers

Very short answer type questions (2 marks)

1. Define heliophytes and sciophytes. Name a plant from your locality that is either heliophyte or sciophyte.

A: Heliophytes: Plants that grow in direct sunlight.

         Sciophytes: Plants that grow in shady places.

 e.g.: Pothos (Money plant)

2. Define population and community.
A: Population: A group of similar individuals belonging to the same species found in an area.
Community: A group of different populations in an area.

 

3. Define communities? Who classified plant communities into hydrophytes, mesophytes and xerophytes?
A: A community is a group of all populations in a area.
Eugen Warming classified plant communities into hydrophytes, mesophytes and xerophytes.

 

4. Hydrophytes show reduced xylem. Why?
A: In hydrophytes all submerged organs are able to absorb water. So there is no need for internal water conduction from roots to shoots. Hence hydrophytes show reduced xylem.

 

SHORT ANSWER TYPE QUESTIONS:
1. What are hydrophytes? Briefly discuss the different kinds of hydrophytes with examples.
A: Plants that grow in water or in very wet places are called hydrophytes.
        They may be classified into:

1) Free floating hydrophytes: They do not have any contact with soil and float freely on water. e.g.: Pistia, Lemna, Salvinia
2) Rooted hydrophytes with floating leaves: Roots are fixed in the mud but leaves float on water due to long petioles. e.g.: Nymphaea, Victoria
3) Submerged suspended hydrophytes: They are completely submerged but not rooted in the mud. e.g.: Hydrilla, Utricularia
4) Submerged rooted hydrophytes: They are completely submerged and rooted to the substratum. e.g.: Vallisnaria
5) Amphibious plants: They live partly in water and partly in air. e.g.: Saggitaria, Typha, Limnophila

 

2. Write a brief account on classification of xerophytes.
A: Xerophytes grow in habitats deficient in water.
         They may be classified into:
1) Ephemerals: They are annuals which complete their life cycle within a very short periods. e.g.: Tribulus.

2) Succulents: These xerophytes store water in their parts in the form of mucilage when it is available and swell up. They use this stored water during dry periods. e.g.: Opuntia (Stem succulent), Aloe (leaf succulent) and Asparagus (leaf succulent).
3) Non-succulents: These are perennials which can withstand prolonged period of drought.
e.g.: Casuarina

 

3. Give in detail the anatomical adaptations shown by xerophytes.
A:  Anatomical adaptations in xerophytes:
* Epidermis is multilayered and covered with thick cuticle.
* It may contain silica crystals.
* Stomata are present on lower epidermis and sunken in position.
* Mechanical tissues (Sclerenchyma) are well developed.
* Vascular tissues are also well developed.

 

4. Define ecosystem/ecological services. Explain in brief with regard to pollination.
A: Ecosystem services or ecological services are life supporting and life enhancing services.

Ecosystem service – pollination
* Decline in pollinator activity results in loss of crop yield.
* Nearly one lakh species of invertebrates and 1035 species of vertebrates act as pollinators.
* According to US Fish and Wildlife Service lists 50 pollinator species are threatened or endangered.
* Causes of decline in pollinators are deforestation and chemical pesticides.

 

5. What measure do you suggest to protect the pollinators?
A: Measures to protect pollinators:
* Growing native flowering plants in our surroundings.
* Reducing use of chemical pesticides.
* Building artificial habitats like butterfly gardens, bee boards and bee boxes.
* Protection of pollinators to be on the agenda of agricultural policies.

Long Answer type questions:
1. Give an account of ecosystem services with reference to carbon fixation and oxygen release.
A: Ecosystem service – carbon fixation
* Forests accumulate large amounts of carbondioxide in the form of timber and provide oxygen in return.
* Based on the equation of photosynthesis the amount of CO2 absorbed may be calculated.
* 264 gms of CO2, 108 gms of water and 677.2 K.cal of solar energy produce 180 gms of glucose and 193 gms of oxygen.
* 180 gms of glucose can be converted into 162 gms of polysaccharide or dry matter.
* Therefore for every one gram of dry matter produced 1.63 gms of CO2 is fixed.
* If a standard cost per unit CO2 fixed is multiplied with the total fixed CO2 the economic value of CO2 can be obtained.
* Natural ecosystems reduce green house gases and also help to moderate regional and local weather.
* Carbon tax system established by many countries also reduces green house gases.
* Afforestation is an effective measure to prevent global warming.

 

Ecosystem service – oxygen release:
* Trees and planktons produce oxygen during photosynthesis.
* The amount of oxygen produced by a tree depends on the species of the tree, its age, its health and its surroundings.
* A mature leafy tree produces oxygen enough for 10 people to inhale in a year.
* Submerged macrophytes (larger plants in water) enrich dissolved oxygen in water.
* The plants and planktons are called "the lungs of the world" because they exhale billions of tonnes of oxygen.
* Some microbes like cyanobacteria release oxygen directly while others produce oxygen indirectly.

Posted Date : 29-07-2021

గమనిక : ప్రతిభ.ఈనాడు.నెట్‌లో కనిపించే వ్యాపార ప్రకటనలు వివిధ దేశాల్లోని వ్యాపారులు, సంస్థల నుంచి వస్తాయి. మరి కొన్ని ప్రకటనలు పాఠకుల అభిరుచి మేరకు కృత్రిమ మేధస్సు సాంకేతికత సాయంతో ప్రదర్శితమవుతుంటాయి. ఆ ప్రకటనల్లోని ఉత్పత్తులను లేదా సేవలను పాఠకులు స్వయంగా విచారించుకొని, జాగ్రత్తగా పరిశీలించి కొనుక్కోవాలి లేదా వినియోగించుకోవాలి. వాటి నాణ్యత లేదా లోపాలతో ఈనాడు యాజమాన్యానికి ఎలాంటి సంబంధం లేదు. ఈ విషయంలో ఉత్తర ప్రత్యుత్తరాలకు, ఈ-మెయిల్స్ కి, ఇంకా ఇతర రూపాల్లో సమాచార మార్పిడికి తావు లేదు. ఫిర్యాదులు స్వీకరించడం కుదరదు. పాఠకులు గమనించి, సహకరించాలని మనవి.

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