{"id":12479,"date":"2024-03-28T10:53:11","date_gmt":"2024-03-28T05:23:11","guid":{"rendered":"https:\/\/wordpress-505192-1602719.cloudwaysapps.com\/?p=12479"},"modified":"2024-03-28T11:22:17","modified_gmt":"2024-03-28T05:52:17","slug":"samacheer-kalvi-12th-bio-botany-solutions-chapter-6","status":"publish","type":"post","link":"https:\/\/samacheerguru.com\/samacheer-kalvi-12th-bio-botany-solutions-chapter-6\/","title":{"rendered":"Samacheer Kalvi 12th Bio Botany Solutions Chapter 6 Principles of Ecology"},"content":{"rendered":"

Are you searching for the Tamilnadu State Board Class 12th Bio Botany Solutions Chapter 6 Principles of Ecology Questions and Answers. Then, you are at the correct place. Verify all the Bio Botany Solutions subject concepts and begin your practice for the exam. Every concept in Samacheer Kalvi 12th Bio Botany Book Solutions<\/a> Chapter 6 Principles of Ecology solutions is explained in detail. Students can easily create an interest in Bio Botany Solutions by referring to Samacheer Kalvi Class 12th Bio Botany Solutions pdf.<\/p>\n

Tamilnadu Samacheer Kalvi 12th Bio Botany Solutions Chapter 6 Principles of Ecology<\/h2>\n

Get updated Samacheer Kalvi Solutions pdf and download it for free. Don’t pay a single penny to get a free pdf of Tamilnadu State Board Board Solutions for Class 12th Bio Botany Solutions Chapter 6 Principles of Ecology Questions and Answers. The Samacheer Kalvi Class 12th Bio Botany Solutions Pdf material is developed as per the latest exam pattern. Get access to all the topics available on Class 12th Samacheer Kalvi Bio Botany Solutions.<\/p>\n

Samacheer Kalvi 12th Bio Botany Principles of Ecology Text Book Back Questions and Answers<\/h3>\n

Question 1.
\nArrange the correct sequence of ecological hierarchy starting from lower to higher level.
\n(a) Individual organism \u2192 Population Landscape \u2192 Ecosystem
\n(b) Landscape \u2192 Ecosystem \u2192 Biome \u2192 Biosphere
\n(c) community \u2192 Ecosystem \u2192 Landscape \u2192 Biome
\n(d) Population \u2192 organism \u2192 Biome \u2192 Landscape
\nAnswer:
\n(a) Individual organism \u2192 Population Landscape \u2192 Ecosystem<\/p>\n

Question 2.
\nEcology is the study of an individual species is called
\n(i) Community ecology
\n(ii) Autecology
\n(iii) Species ecology
\n(iv) Synecology
\n(a) i only
\n(b) ii only
\n(c) i and iv only
\n(d) ii and iii only
\nAnswer:
\n(b) ii only<\/p>\n

Question 3.
\nA specific place in an ecosystem, where an organism lives and performs its functions is
\n(a) habitat
\n(b) niche
\n(c) landscape
\n(d) biome
\nAnswer:
\n(b) niche<\/p>\n

Question 4.
\nRead the given statements and select the correct option.
\n(i) Hydrophytes possess aerenchyma to support themselves in water.
\n(ii) Seeds of Viscum are positively photoblastic as they germinate only in presence of light.
\n(iii) Hygroscopic water is the only soil water available to roots of plant growing in soil as it is present inside the micropores.
\n(iv) High temperature reduces use of water and solute absorption by roots.
\n(a) i, ii, and iii only
\n(b) ii, iii and iv
\n(c) ii and iii only
\n(d) i and ii only
\nAnswer:
\n(d) i and ii only<\/p>\n

Question 5.
\nWhich of the given plant produces cardiac glycosides?
\n(a) Calotropis
\n(b) Acacia
\n(c) Nepenthes
\n(d) Utricularia
\nAnswer:
\n(a) Calotropis<\/p>\n

Question 6.
\nRead the given statements and select the correct option.
\n(i) Loamy soil is best suited for plant growth as it contains a mixture of silt, sand and clay.
\n(ii) The process of humification is slow in case of organic remains containing a large amount of lignin and cellulose.
\n(iii) Capillary water is the only water available to plant roots as it is present inside the micropores.
\n(iv) Leaves of shade plant have more total chlorophyll per reaction centre, low ratio of chi a and chi b are usually thinner leaves.
\n(a) i, ii and iii only
\n(b) ii, iii and iv only
\n(c) i, ii and iv only
\n(d) ii and iii only
\nAnswer:
\n(d) ii and iii only<\/p>\n

Question 7.
\nRead the given statements and select the correct option.
\nStatement A: Cattle do not graze on weeds of Calotropis.
\nStatement B: Calotropis have thorns and spines, as defense against herbivores.
\n(a) Both statements A and B are incorrect.
\n(b) Statement A is correct but statement B is incorrect.
\n(c) Both statements A and B are correct but statement B is not the correct explanation of statement A.
\n(d) Both statements A and B are correct and statement B is the correct explanation of statement A.
\nAnswer:
\n(b) Statement A is correct but statement B is incorrect.<\/p>\n

Question 8.
\nIn soil water available for plants is
\n(a) gravitational water
\n(b) chemically bound water
\n(c) capillary water
\n(d) hygroscopic water
\nAnswer:
\n(c) capillary water<\/p>\n

Question 9.
\nRead the following statements and fill up the blanks with correct option.<\/p>\n

    \n
  1. Total soil water content in soil is called ______<\/li>\n
  2. Soil water not available to plants is called ______<\/li>\n
  3. Soil water available to plants is called ______<\/li>\n<\/ol>\n

    \"Samacheer
    \nAnswer:
    \n(a) Holard, Echard and Cheresard<\/p>\n

    Question 10.
    \nColumn I represent the size of the soil particles components. Which of the following is correct match for the Column I and Column II<\/p>\n

    \"Samacheer
    \n\"Samacheer
    \nAnswer:
    \n(c) i, ii, i and iv<\/p>\n

    Question 11.
    \nThe plant of this group are adapted to live partly in water and partly above substratum and free from water
    \n(a) Xerophytes
    \n(b) Mesophytes
    \n(c) Hydrophytes
    \n(d) Halophytes
    \nAnswer:
    \n(b) Mesophytes<\/p>\n

    Question 12.
    \nIdentify the A, B, C and D in the given table:
    \n\"Samacheer
    \n\"Samacheer
    \nAnswer:
    \n(a) (+) Parasitism (-) Amensalism<\/p>\n

    Question 13.
    \nOphrys an orchid resembling the female of an insect so as to able to get pollinated is due to phenomenon of
    \n(a) Myrmecophily
    \n(b) Ecological equivalents
    \n(c) Mimicry
    \n(d) None of these
    \nAnswer:
    \n(c) Mimicry<\/p>\n

    Question 14.
    \nA free living nitrogen fixing cyanobacterium which can also form symbiotic association with the water fem Azolla
    \n(a) Nostoc
    \n(b) Anabaena
    \n(c) Chlorella
    \n(d) Rhizobium
    \nAnswer:
    \n(b) Anabaena<\/p>\n

    Question 15.
    \nPedogenesis refers to
    \n(a) Fossils
    \n(b) Water
    \n(c) Population
    \n(d) Soil
    \nAnswer:
    \n(d) Soil<\/p>\n

    Question 16.
    \nMycorrhiza promotes plant growth by
    \n(a) Serving as a plant growth regulators
    \n(b) Absorbing inorganic ions from soil
    \n(c) Helping the plant in utilizing atmospheric nitrogen
    \n(d) Protecting the plant from infection
    \nAnswer:
    \n(d) Protecting the plant from infection<\/p>\n

    Question 17.
    \nWhich of the following plant has a non-succulent xerophytic and thick leathery leaves with waxy coating?
    \n(a) Bryophyllum
    \n(b) Ruscus
    \n(c) Nerium
    \n(d) Calotropis
    \nAnswer:
    \n(d) Calotropis<\/p>\n

    Question 18.
    \nIn a fresh water environment like pond, rooted autotrophs are
    \n(a) Nymphaea and typha
    \n(b) Ceratophyllum and Utricularia
    \n(c) Wolffia and pistia
    \n(d) Azolla and lemna
    \nAnswer:
    \n(a) Nymphaea and typha<\/p>\n

    Question 19.
    \nMatch the following and choose the correct combination from the options given below:
    \n\"Samacheer
    \nAnswer:
    \n(d) iv, iii, ii, v and i<\/p>\n

    Question 20.
    \nStrong, sharp spines that get attached to animal’s feet are found in the fruits of
    \n(a) Argemone
    \n(b) Ecballium
    \n(c) Heraitier
    \n(d) Crossandra
    \nAnswer:
    \n(a) Argemone<\/p>\n

    Question 21.
    \nSticky glands of Boerhaavia and Cleome support
    \n(a) Anemochory
    \n(b) Zoochory
    \n(c) Autochory
    \n(d) Hydrochory
    \nAnswer:
    \n(b) Zoochory<\/p>\n

    Question 22.
    \nDefine ecology.
    \nAnswer:
    \nEcology is the study of the reciprocal relationship between living organisms and their environment.<\/p>\n

    Question 23.
    \nWhat is ecological hierarchy?
    \nName the levels of ecological hierarchy.
    \nAnswer:
    \nThe interaction of organisms with their environment results in the establishment of grouping of organisms which is called ecological hierarchy.
    \n\"Samacheer<\/p>\n

    Question 24.
    \nWhat are ecological equivalents? Give one example.
    \nAnswer:
    \nTaxonomically different species occupying similar habitats (Niches) in different geographical regions are called Ecological equivalents.
    \nE.g: Certain species of epiphytic orchids of Western Ghats of India differ from the epiphytic orchids of South America. But they are epiphytes.<\/p>\n

    Question 25.
    \nDistinguish habitat and niche.
    \nAnswer:
    \nHabitat:<\/p>\n

      \n
    1. A specific physical space occupied by an organism (species).<\/li>\n
    2. Same habitat may be shared by many organisms (species).<\/li>\n
    3. Habitat specificity is exhibited by organism.<\/li>\n<\/ol>\n

      Niche:<\/p>\n

        \n
      1. a functional space occupied by an organism in the same eco-system<\/li>\n
      2. A single niche is the occupied by a single species<\/li>\n
      3. Organisms may change their niche with time and season<\/li>\n<\/ol>\n

        Question 26.
        \nWhy are some organisms called as eurythermals and some others as stenohaline?
        \nAnswer:<\/p>\n

          \n
        1. Eurythermal: Organisms which can tolerate a wide range of temperature fluctuations.
          \nExample: Zostera.<\/li>\n
        2. Stenothermal: Organisms which can tolerate only small range of temperature variations.
          \nExample: Mango.<\/li>\n<\/ol>\n

          Question 27.
          \n\u2018Green algae are not likely to be found in the deepest strata of the ocean\u2019. Give at least one reason.
          \nAnswer:
          \nAs the name indicates, green algae possess photosynthetic pigments which use the light as energy source for survival and they are not found in deepest sea since there is lack of light.<\/p>\n

          Question 28
          \nWhat is Phytoremediation?
          \nAnswer:
          \nPhytoremediation refers to the using of living green plants to overcome soil or water contamination.
          \nE.g: Growing Eichhomia in cadmium enriched soil reduces the level of cadmium.<\/p>\n

          Question 29.
          \nWhat is Albedo effect and write their effects?
          \nAnswer:
          \nGases let out to atmosphere causes climatic change. Emission of dust and aerosols from industries, automobiles, forest fire,\u00a0 and DMS (dimethyl sulphur) play an important role in disturbing the temperature level of any region. Aerosols with small particles is reflecting the solar radiation entering the atmosphere. This is known as Albedo effect.<\/p>\n

          Question 30.
          \nThe organic horizon is generally absent from agricultural soils because tilling, e.g., plowing, buries organic matter. Why is an organic horizon generally absent in desert soils?
          \nAnswer:
          \nOrganic horizon is generally absent in deserts because of low content of organic matter due to scarcity of plant and animal remains or excreta.<\/p>\n

          Question 31.
          \nSoil formation can be initiated by biological organisms. Explain how?
          \nAnswer:
          \nSoil formation is initiated by the biological weathering process. Biological weathering takes place when organisms like bacteria, fungi, lichens and plants help in the breakdown of rocks through the production of acids and certain chemical substances.<\/p>\n

          Question 32.
          \nSandy soil is not suitable for cultivation. Explain why?
          \nAnswer:
          \nSandy soil has a high porosity leading to decreased water retention hence unfit for cultivation.<\/p>\n

          Question 33.
          \nDescribe the mutual relationship between the fig and wasp and comment on the phenomenon that operates in this relationship.
          \nAnswer:
          \nWasps present in the figs is an example of mutualism where both the interacting species are benefitted from the obligate association. Wasps acts as a pollinating agents for figs intum larvae of wasps are nourished and protected by fruits of figs.<\/p>\n

          Question 34.
          \nLichen is considered as a good example of obligate mutualism. Explain.
          \nAnswer:
          \nLichen is a mutual association of an alga and a fungus, where the algal partner nourishes and provides shelter to fungi, intum fungi confers protection from bacterial infections and also maintains moisture for algal growth.<\/p>\n

          Question 35.
          \nWhat is mutualism? Mention any two example where the organisms involved are commercially exploited in modern agriculture.
          \nAnswer:<\/p>\n

            \n
          1. Mutualism is an interaction between two species of organisms in which both are benefitted from the obligate<\/li>\n
          2. association. Nitrogen fixing cyanobacteria associated with Azolla (a fern) and Rhizobium found in the root nodules of leguminous plant are used in the field of agriculture to increase the soil fertility.<\/li>\n<\/ol>\n

            Question 36.
            \nList any two adaptive features evolved in parasites enabling them to live successfully on their host?
            \nAnswer:
            \nPresence of haustorial roots inside the host plant to absorb nutrients.<\/p>\n

            Question 37.
            \nMention any two significant roles of predation plays in nature.
            \nAnswer:
            \nPredation maintains the stability of food chain in an ecosystem. Population of the insects and small animals are in control due to predation or else it may lead to overgrazing and browsing thereby altering the vegetation.<\/p>\n

            Question 38.
            \nHow does an orchid ophrys ensures its pollination by bees ?
            \nAnswer:
            \nThe plant, Ophrys an orchid, the flower looks like a female insect to attract the male insect to get pollinated by the male insect and it is otherwise called \u2018floral mimicry \u2018<\/p>\n

            Question 39.
            \nWater is very essential for life. Write any three features for plants which enable them to survive in water scarce environment.
            \nAnswer:<\/p>\n

              \n
            1. Presence of highly developed root system to absorb water.<\/li>\n
            2. Stems and leaves are covered with waxing coating or dense hairs to avoid transpirational loss.<\/li>\n
            3. Modified leaves generally leathery and shiny to reflect light and heat.<\/li>\n<\/ol>\n

              Question 40.
              \nWhy do submerged plants receive weak illumination than exposed floating plants in a lake?
              \nAnswer:
              \nSubmerged plants like Vallisneria receive dim illumination because majority of the light are reflected back by the water surface whereas, the floating hydrophytes receive and absorb maximum light as they are on the water surface.<\/p>\n

              Question 41.
              \nWhat is vivipary? Name a plant group which exhibits vivipary.
              \nAnswer:
              \nViviparity is the phenomenon, where the seeds germinate and then starts developing to some extent before they detach from the parent plant body. In plant, it is noticed in Halophytes like Rhizophora.<\/p>\n

              Question 42.
              \nWhat is thermal stratification? Mention their types.
              \nAnswer:
              \nThermal Stratification is usually found in aquatic habitat. The change in the temperature profile with increasing depth in a water body is called thermal stratification. There are three kinds of thermal stratifications.<\/p>\n

                \n
              1. Epilimnion – The upper layer of warmer water.<\/li>\n
              2. Metalimnion – The middle layer with a zone of gradual decrease in temperature.<\/li>\n
              3. Hypolimnion – The bottom layer of colder water.<\/li>\n<\/ol>\n

                Question 43.
                \nHow is rhytidome act as the structural defence by plants against fire?
                \nAnswer:
                \nRhytidome is the structural defense by plants against fire. The outer bark of trees which extends to the last formed periderm is called Rhytidome. It is composed of multiple layers of suberized periderm, cortical and phloem tissues. It protects the stem against fire, water loss, invasion of insects and prevents infections by microorganisms.<\/p>\n

                Question 44.
                \nWhat is myrmecophily?
                \nAnswer:
                \nSometimes, ants take their shelter on some trees such as Mango, Litchi, Jamun and Acacia, etc. These ants act as body guards of the plants against any disturbing agent and the plants in turn provide food and shelter to these ants. This phenomenon is known as Myrmecophily. Example: Acacia and its ants.<\/p>\n

                Question 45.
                \nWhat is seed ball?
                \nAnswer:
                \nSeed ball is an ancient Japanese technique of encasing seeds in a mixture of clay and soil humus (also in cow dung) and scattering them on to suitable ground, not planting of trees manually. This method is suitable for barren and degraded lands for tree regeneration and vegetation before monsoon period where the suitable dispersal agents become rare.<\/p>\n

                Question 46.
                \nHow is anemochory differ from zoochory?
                \nAnswer:
                \nAnemochory:<\/p>\n

                  \n
                1. Anemochory refers to the seed dispersal by wind.<\/li>\n
                2. Anemochory seeds are very minute and may have wings or feathery appendages for dispersal.<\/li>\n
                3. E.g: Orchids<\/li>\n<\/ol>\n

                  Zoochory:<\/p>\n

                    \n
                  1. Zoochory refers to the seed dispersal by animals.<\/li>\n
                  2. Zoochory seeds and fruits are very fleshy and succulent and sticky they may have hooks to adhere to the body of animals.<\/li>\n
                  3. E.g: Mango<\/li>\n<\/ol>\n

                    Question 47.
                    \nWhat is co-evolution?
                    \nAnswer:
                    \nThe interaction between organisms, when continues for generations, involves reciprocal changes in genetic and morphological characters of both organisms. This type of evolution is called Co-evolution. It is a kind of co-adaptation and mutual change among interactive species.
                    \nExamples:<\/p>\n

                      \n
                    • Corolla length and proboscis length of butterflies and moths (Habenaria and Moth).<\/li>\n
                    • Bird\u2019s beak shape and flower shape and size.<\/li>\n<\/ul>\n

                      Question 48.
                      \nExplain Raunkiaer classification in the world\u2019s vegetation based on the temperature.
                      \nAnswer:
                      \nRaunkiaer classified the world\u2019s vegetation into the following four types. They are megatherms, mesotherms, microtherms and hekistotherms.<\/p>\n

                      Question 49.
                      \nList out the effects of fire to plants.
                      \nAnswer:
                      \nEffects of fire:<\/p>\n

                        \n
                      1. Fire has a direct lethal effect on plants.<\/li>\n
                      2. Burning scars are the suitable places for the entry of parasitic fungi and insects.<\/li>\n
                      3. It brings out the alteration of light, rainfall, nutrient cycle, fertility of soil, pH, soil flora and fauna.<\/li>\n
                      4. Some fungi which grow in soil of burnt areas are called pyrophilous.<\/li>\n
                      5. Example: Pyronema confluens.<\/li>\n<\/ol>\n

                        Question 50.
                        \nWhat is soil profile? Explain the characters of different soil horizons.
                        \nAnswer:
                        \nSoil is commonly stratified into horizons at different depth. These layers differ in their physical, chemical and biological properties. This succession of super-imposed horizons is called soil profile.
                        \n\"Samacheer<\/p>\n

                        Question 51.
                        \nGive an account of various types of parasitism with examples.
                        \nAnswer:
                        \n(a) Parasitism: It is an interaction between two different species in which the smaller partner (parasite) obtains food from the larger partner (host or plant). So the parasitic species is benefitted while the host species is harmed. Based on the host-parasite relationship, parasitism is classified into two types they are holoparasite and hemiparasite.<\/p>\n

                        (b) Holoparasites: The organisms which are dependent upon the host plants for their entire nutrition are called Holoparasites. They are also called total parasites.
                        \nExamples:<\/p>\n

                          \n
                        • Cuscuta is a total stem parasite of the host plant Acacia, Duranta and many other plants. Cuscuta even gets flower inducing hormone from its host plant.<\/li>\n
                        • Balanophora, orobanche and Refflesia are the total root parasites found on higher plants.<\/li>\n<\/ul>\n

                          (c) Hemiparasites: The organisms which derive only water and minerals from their host plant while synthesizing their own food by photosynthesis are called Hemiparasites. They are also called partial parasites.
                          \nExamples:<\/p>\n

                            \n
                          • Viscum and Loranthus are partial stem parasites.<\/li>\n
                          • Santalum (Sandal Wood) is a partial root parasite.
                            \nThe parasitic plants produce the haustorial roots inside the host plant to absorb nutrients from the vascular tissues of host plants.<\/li>\n<\/ul>\n

                            Question 52.
                            \nExplain different types of hydrophytes with examples.
                            \nAnswer:
                            \nHydrophytes
                            \nThe plants which are living in water or wet places are called hydrophytes. According to their relation to water and air, they are sub-divided into following categories:<\/p>\n

                              \n
                            1. Free floating hydrophytes<\/li>\n
                            2. Rooted-floating hydrophytes<\/li>\n
                            3. Submerged floating hydrophytes<\/li>\n
                            4. Rooted- submerged hydrophytes<\/li>\n
                            5. Amphibious hydrophytes.<\/li>\n<\/ol>\n

                              1. Free floating hydrophytes: These plants float freely on the surface of water. They remain in contact with water and air, but not with soil. Examples: Eichhornia, Pistia and Wolffia (smallest flowering plant).<\/p>\n

                              2. Rooted floating hydrophytes: In these plants, the roots are fixed in mud, but their leaves and flowers are floating on the surface of water. These plants are in contact with soil, water and air. Examples: Nelumbo, Nymphaea, Potomogeton and Marsilea.<\/p>\n

                              3. Submerged floating hydrophytes: These plants are completely submerged in water and not in contact with soil and air. Examples: Ceratophyllum and Utricularia.<\/p>\n

                              4. Rooted-submerged hydrophytes: These plants are completely submerged in water and rooted in soil and not in contact with air. Examples: Hydrilla, Vallisneria and Isoetes.<\/p>\n

                              5. Amphibious hydrophytes (Rooted emergent hydrophytes): These plants are adapted to both aquatic and terrestrial modes of life. They grow in shallow water. Examples: Ranunculus, Typha and Sagittaria.<\/p>\n

                              Question 53.
                              \nEnumerate the anatomical adaptations of xerophytes.
                              \nAnswer:<\/p>\n

                                \n
                              1. Presence of multilayered epidermis with heavy cuticle to prevent water loss due to transpiration.<\/li>\n
                              2. Hypodermis is well developed with sclerenchymatous tissues.<\/li>\n
                              3. Sunken shaped stomata are present only in the lower epidermis with hairs in the sunken pits.<\/li>\n
                              4. Scotoactive type of stomata found in succulent plants.<\/li>\n
                              5. Vascular bundles are well developed with several layered bundle sheath.<\/li>\n
                              6. Mesophyll is well differentiated into palisade and spongy parenchyma.<\/li>\n
                              7. In succulents, the stem possess a water storage region.<\/li>\n<\/ol>\n

                                Question 54.
                                \nList out any five morphological adaptations of halophytes.
                                \nAnswer:
                                \nMorphological adaptations<\/p>\n

                                  \n
                                1. The temperate halophytes are herbaceous but the tropical halophytes are mostly bushy.<\/li>\n
                                2. In addition to the normal roots, many stilt roots are developed.<\/li>\n
                                3. A special type of negatively geotropic roots called pneumatophores with pneumathodes to get sufficient aeration are also present. They are called breathing roots.
                                  \nExample: Avicennia.<\/li>\n
                                4. Presence of thick cuticle on the aerial parts of the plant body.<\/li>\n
                                5. Leaves are thick, entire, succulent and glossy. Some species are aphyllous (without leaves).<\/li>\n<\/ol>\n

                                  Question 55.
                                  \nWhat are the advantages of seed dispersal?
                                  \nAnswer:
                                  \nAdvantages of seed dispersal:<\/p>\n

                                    \n
                                  1. Seeds escape from mortality near the parent plants due to predation by animals or getting diseases and also avoiding competition.<\/li>\n
                                  2. Dispersal also gives a chance to occupy favourable sites for growth.<\/li>\n
                                  3. It is an important process in the movement of plant genes particularly this is the only method available for self-fertilized flowers and maternally transmitted genes in outcrossing plants.<\/li>\n
                                  4. Seed dispersal by animals help in conservation of many species even in human altered ecosystems.<\/li>\n
                                  5. Understanding of fruits and seed dispersal acts as a key for proper functioning and establishment of many ecosystems from deserts to evergreen forests and also for the maintenance of biodiversity conservation and restoration of ecosystems.<\/li>\n<\/ol>\n

                                    Question 56.
                                    \nDescribe dispersal of fruit and seeds by animals.
                                    \nAnswer:
                                    \nBirds and mammals, including human beings play an efficient and important role in the dispersal of fruit and seeds. They have the following devices.<\/p>\n

                                      \n
                                    1. Hooked fruit: The surface of the fruit or seeds have hooks (Xanthium), barbs (Andropogon), spines (Aristida) by means of which they adhere to the body of animals or clothes of human beings and get dispersed.<\/li>\n
                                    2. Sticky fruits and seeds:\n
                                        \n
                                      • Some fruits have sticky glandular hairs by which they adhere to the fur of grazing animals. Example: Boerhaavia and Cleome.<\/li>\n
                                      • Some fruits have viscid layer which adhere to the beak of the bird which eat them and when they rub them on to the branch of the tree, they disperse and germinate.
                                        \nExample: Cordia and Alangium.<\/li>\n<\/ul>\n<\/li>\n
                                      • Fleshy fruits: Some fleshy fruits with conspicuous colours are dispersed by human beings to distant places after consumption.<\/li>\n<\/ol>\n

                                        Samacheer Kalvi 12th Bio Botany Principles of Ecology Additional Questions and Answers<\/h3>\n

                                        1 – Mark Questions<\/span><\/p>\n

                                        Question 1.
                                        \nWho is called as the father of Modem Ecology?
                                        \nAnswer:
                                        \nEugene P. Odum<\/p>\n

                                        Question 2.
                                        \nAutoecology deals with the study of ________
                                        \n(a) Community
                                        \n(b) Population
                                        \n(c) Individual species
                                        \n(d) Niche of species
                                        \nAnswer:
                                        \n(c) Individual species<\/p>\n

                                        Question 3.
                                        \nEnvironment of any community is called
                                        \n(a) Paratope
                                        \n(d) Biotope
                                        \n(c) Opitope
                                        \n(d) Biotope
                                        \nAnswer:
                                        \n(d) Biotope<\/p>\n

                                        Question 4.
                                        \nMatch Coloumn I with Column II
                                        \n\"Samacheer
                                        \nAnswer:
                                        \n(a) – iii
                                        \n(b) – i
                                        \n(c) – iv
                                        \n(d) – ii<\/p>\n

                                        Question 5.
                                        \nThe study of soil is called as __________
                                        \n(a) Lithotripsy
                                        \n(b) Lithosphere
                                        \n(c) Pedology
                                        \n(d) Pedology analysis
                                        \nAnswer:
                                        \n(c) Pedology<\/p>\n

                                        Question 6.
                                        \nIdentify the indicators of fire.
                                        \n(a) Pucinia
                                        \n(b) Pyricularia
                                        \n(c) Pyronema
                                        \nAnswer:
                                        \n(c) Pyronema<\/p>\n

                                        Question 7.
                                        \nThe surface features of earth are called __________
                                        \nAnswer:
                                        \nTopography<\/p>\n

                                        Question 8.
                                        \nAmensalism is called as __________
                                        \nAnswer:
                                        \nAntibiosis<\/p>\n

                                        Question 9.
                                        \nis the transition zone between two ecosystems.
                                        \nAnswer:
                                        \nEcotone<\/p>\n

                                        Question 10.
                                        \nMatch the type of species interaction with correct combination. Interaction Type Combination
                                        \n\"Samacheer
                                        \nAnswer:
                                        \n(a) – iii (b) – i (c) – iv (d) – ii<\/p>\n

                                        Question 11.
                                        \nWasps is the fruits of fig is an example for ________ type of species interaction.
                                        \nAnswer:
                                        \nMutualism<\/p>\n

                                        Question 12.
                                        \nStatement 1: Latitudes represent distance from the equator.
                                        \nStatement 2: Height above the seal level from longitude.
                                        \n(a) Statement 1 is correct. Statement 2 is incorrect.
                                        \n(b) Statement 1 is incorrect. Statement 2 is correct.
                                        \n(c) Both the statements are correct.
                                        \n(d) Both the statements are incorrect.
                                        \nAnswer:
                                        \n(a) Statement 1 is correct. Statement 2 is incorrect.<\/p>\n

                                        Question 13.
                                        \nStatement 1: Holoparsites depend totally on other organisms for nutrition.
                                        \nStatement 2: Dumta is holoparasite.
                                        \n(a) Statement 1 is correct. Statement 2 is incorrect.
                                        \n(b) Statement 1 is incorrect. Statement 2 is correct.
                                        \n(c) Both the statements are correct.
                                        \n(d) Both the statements are incorrect.
                                        \nAnswer:
                                        \n(c) Both the statements are correct.<\/p>\n

                                        Question 14.
                                        \nStatement 1: Ephemerals are drought evaders.
                                        \nStatement 2: They are not true xerophytes.
                                        \n(a) Statement 1 is correct. Statement 2 is incorrect.
                                        \n(b) Statement 1 is incorrect. Statement 2 is correct.
                                        \n(c) Both the statements are correct.
                                        \n(d) Both the statements are incorrect.
                                        \nAnswer:
                                        \n(c) Both the statements are correct.<\/p>\n

                                        Question 15.
                                        \nAssertion (A) : Plains and valleys are rich in vegetation
                                        \nReason (R): Slow drain of surface water and better water retention is noticed.
                                        \n(a) A is true R is false
                                        \n(b) R explains A
                                        \n(c) A and R are false
                                        \n(d) A and R are true. But R doesnot explains A
                                        \nAnswer:
                                        \n(b) R explains A<\/p>\n

                                        Question 16.
                                        \nUtricularia is a _______
                                        \n(a) Rooted floating hydrophyte
                                        \n(b) Submerged floating hydrophyte
                                        \n(c) Rooted submerged hydrophyte
                                        \n(d) Amphibious hydrophyte
                                        \nAnswer:
                                        \n(b) Submerged floating hydrophyte<\/p>\n

                                        Question 17.
                                        \nEarth day is observed on
                                        \n(a) April 22nd
                                        \n(b) March 21st
                                        \n(c) July 07th
                                        \n(d) September 16th
                                        \nAnswer:
                                        \n(a) April 22nd<\/p>\n

                                        Question 18.
                                        \nPlants in sandy soils are commonly called as _______
                                        \nAnswer:
                                        \nPsammophytes<\/p>\n

                                        2 – Mark Questions<\/span><\/p>\n

                                        Question 1.
                                        \nHow Earnest Haeckel defined ecology?
                                        \nAnswer:
                                        \nEarnest Haeckel defined \u201cEcology is the study of the reciprocal relationship between living organisms and their environment.\u201d<\/p>\n

                                        Question 2.
                                        \nWhat is ecological hierarchy?
                                        \nAnswer:
                                        \nThe interaction of organisms with their environment results in the establishment of grouping of organisms which is called ecological hierarchy.<\/p>\n

                                        Question 3.
                                        \nSequentially arrange the different units of ecological hierarchy.
                                        \nAnswer:
                                        \n\"Samacheer<\/p>\n

                                        Question 4.
                                        \nDefine<\/p>\n

                                          \n
                                        1. Autecology<\/li>\n
                                        2. Synecology.<\/li>\n<\/ol>\n

                                          Answer:<\/p>\n

                                            \n
                                          1. Autecology is the ecology of an individual species and is also called species ecology.<\/li>\n
                                          2. Synecology is the ecology of a population or community with one or more species and also called as community ecology.<\/li>\n<\/ol>\n

                                            Question 5.
                                            \nWhat is Niche?
                                            \nAnswer:
                                            \nAn ecological niche refers to an organism\u2019s place in the biotic environment and its functional role in an ecosystem.<\/p>\n

                                            Question 6.
                                            \nWhat are ecological factors?
                                            \nAnswer:
                                            \nThe environment (surrounding) includes physical, chemical and biological components. When a component surrounding an organism affects the life of an organism, it becomes a factor. All such factors together are called environmental factors or ecological factors.<\/p>\n

                                            Question 7.
                                            \nName the climatic factors that affect plant life.
                                            \nAnswer:
                                            \nLight, Temperature, Water, Wind and Fire.<\/p>\n

                                            Question 8.
                                            \nName any four physiological processes in plants, where the light plays a crucial role.
                                            \nAnswer:<\/p>\n

                                              \n
                                            1. Photosynthesis<\/li>\n
                                            2. Transpiration<\/li>\n
                                            3. Seed germination<\/li>\n
                                            4. Flowering<\/li>\n<\/ol>\n

                                              Question 9.
                                              \nHeliophytes differ from Sciophytes. How?
                                              \nAnswer:
                                              \nHeliophytes – Light loving plants. Example: Angiosperms.
                                              \nSciophytes – Shade loving plants. Example: Bryophytes and Pteridophytes.<\/p>\n

                                              Question 10.
                                              \nBased on temperature prevalence, Raunkiaer classified world\u2019s vegetation into four types. Name them.
                                              \nAnswer:
                                              \nRaunkiaer classified the world\u2019s vegetation into the following four types. They are megatherms, mesotherms, microtherms and hekistotherms.<\/p>\n

                                              Question 11.
                                              \nDistinguish between evergreen forests and sclerophyllous forests.
                                              \nAnswer:
                                              \nEvergreen Forests: Found where heavy rainfall occurs throughout the year.
                                              \nSclerophyllous Forests: Found where heavy rainfall occurs during winter and low rainfall during summer.<\/p>\n

                                              Question 12.
                                              \nWhat does the term \u2018Timber line\u2019 refers to?
                                              \nAnswer:
                                              \nTimber line is an imaginary line in a mountain or higher areas of land that marks the level above which trees do not grow. The altitudinal limit of normal tree growth is about 3000 to 4000 m.<\/p>\n

                                              Question 13.
                                              \nCompare Euryhaline organisms with stenohaline organisms.
                                              \nAnswer:<\/p>\n

                                                \n
                                              1. Euryhaline: Organisms which can live in water with wide range of salinity. Examples: Marine algae and marina angiosperms.<\/li>\n
                                              2. Stenohaline: Organisms which can withstand only small range of salinity. Example: Plants of estuaries.<\/li>\n<\/ol>\n

                                                Question 14.
                                                \nWrite the composition of gases in atmosphere.
                                                \nAnswer:
                                                \nNitrogen -78% , Oxygen -21%, Carbon-di-oxide -0.03%, Argon and other gases – 0.93%.<\/p>\n

                                                Question 15.
                                                \nWhat is Albedo effect?
                                                \nAnswer:
                                                \nGases let out to atmosphere causes climatic change. Emission of dust and aerosols from industries, automobiles, forest fire, S02 and DMS (dimethyl sulphur) play an important role in disturbing the temperature level of any region. Aerosols with small particles is reflecting the solar radiation entering the atmosphere. This is known as Albedo effect.<\/p>\n

                                                Question 16.
                                                \nPoint any two adverse effects of fire in an environment.
                                                \nAnswer:<\/p>\n

                                                  \n
                                                1. Fire has a direct lethal effect on plants.<\/li>\n
                                                2. It brings out the alteration of light, rainfall, nutrient cycle, fertility of soil, pH, soil flora and fauna<\/li>\n<\/ol>\n

                                                  Question 17.
                                                  \nPyronema confluens is the indicator of fire – comment.
                                                  \nAnswer:
                                                  \nPyronema confluens is a fungus which grow on the soil of burnt or fire disturbed areas. Hence it is called as indicator of fire.<\/p>\n

                                                  Question 18.
                                                  \nWhat are edaphic factors?
                                                  \nAnswer:
                                                  \nEdaphic factors are the abiotic factors related to soil, include the physical and chemical composition of the soil formed in a particular area.<\/p>\n

                                                  Question 19.
                                                  \nName the study that deals with soil factors. Also mention the optimal soil pH for crop cultivation.
                                                  \nAnswer:
                                                  \nThe study of soil is called pedology. The best pH of soil for crop cultivation is 5.5 to 6.8.<\/p>\n

                                                  Question 20.
                                                  \nDefine soil profile.
                                                  \nAnswer:
                                                  \nSoil is commonly stratified into horizons at different depth. These layers differ in their physical, chemical and biological properties. This succession of super-imposed horizons is called soil profile.<\/p>\n

                                                  Question 21.
                                                  \nGiven below are few types of plants. Mention their habitats.<\/p>\n

                                                    \n
                                                  1. Halophytes<\/li>\n
                                                  2. Chasmophytes<\/li>\n
                                                  3. Cryophytes<\/li>\n
                                                  4. Psammophytes.<\/li>\n<\/ol>\n

                                                    Answer:<\/p>\n

                                                      \n
                                                    1. Halophytes: Plants living in saline soils.<\/li>\n
                                                    2. Chasmophytes: Plants living in rocky crevices.<\/li>\n
                                                    3. Cryophytes: Plants living in ice surface.<\/li>\n
                                                    4. Psammophytes: Plants living in sandy soils.<\/li>\n<\/ol>\n

                                                      Question 22.
                                                      \nMention any four topographic factors that affect vegetation.
                                                      \nAnswer:<\/p>\n

                                                        \n
                                                      1. Latitude<\/li>\n
                                                      2. Altitude<\/li>\n
                                                      3. Direction of mountain and<\/li>\n
                                                      4. Steepness of mountain.<\/li>\n<\/ol>\n

                                                        Question 23.
                                                        \nHow the steepness of mountain affects the vegetation?
                                                        \nAnswer:
                                                        \nThe steepness of the mountain or hill allows the rain to run off. As a result the loss of water causes water deficit and quick erosion of the top soil resulting in poor vegetation. On the other hand, the plains and valley are rich in vegetation due to the slow drain of surface water and better retention of water in the soil.<\/p>\n

                                                        Question 24.
                                                        \nName any two positive interactions with an example for each.
                                                        \nAnswer:<\/p>\n

                                                          \n
                                                        1. Mutualism – E.g: Lichen<\/li>\n
                                                        2. Commensalism – E.g: Orchids.<\/li>\n<\/ol>\n

                                                          Question 25.
                                                          \nDefine mutualism with an example.
                                                          \nAnswer:
                                                          \nMutualism is an interaction between two species of organisms in which both are benefitted from the obligate association. E.g: Lichens (alga with fungus).<\/p>\n

                                                          Question 26.
                                                          \nWhat is the principle of commensalism?
                                                          \nAnswer:
                                                          \nCommensalism is an interaction between two organisms in which one is benefitted and the other is neither benefitted nor harmed. The species that derives benefit is called the commensal, while the other species is called the host.<\/p>\n

                                                          Question 27.
                                                          \nSpecify the type of interactions between the given pair of species.<\/p>\n

                                                            \n
                                                          1. Spanish moss and Oak tree<\/li>\n
                                                          2. Cuscuta and Acacia<\/li>\n
                                                          3. Nepenthes and Ants<\/li>\n
                                                          4. Alga and fungus<\/li>\n<\/ol>\n

                                                            Answer:<\/p>\n

                                                              \n
                                                            1. Commensalism<\/li>\n
                                                            2. Parasitism<\/li>\n
                                                            3. Predation<\/li>\n
                                                            4. Mutualism<\/li>\n<\/ol>\n

                                                              Question 28.
                                                              \nExplain the concept of proto co-operation.
                                                              \nAnswer:
                                                              \nProto Co-operation is an interaction between organisms of different species in which both organisms benefit but neither is dependent on the relationship. Example: Soil bacteria \/ fungi and plants growing in the soil.<\/p>\n

                                                              Question 29.
                                                              \nWhat are Holoparasites? Give example.
                                                              \nAnswer:
                                                              \nThe organisms which are dependent upon the host plants for their entire nutrition are called Holoparasites. They are also called total parasites.
                                                              \nExample: Cuscuta is a total stem parasite of the host plant Acacia.<\/p>\n

                                                              Question 30.
                                                              \nWhat are hemiparasites? Give example.
                                                              \nAnswer:
                                                              \nHemiparasites is the organisms which derive only water and minerals from their host plant while synthesizing their own food by photosynthesis are called Hemiparasites. They are also called partial parasites.
                                                              \nExample: Viscum.<\/p>\n

                                                              Question 31.
                                                              \nCite an example for partial stem parasite and partial root parasite.
                                                              \nAnswer:<\/p>\n

                                                                \n
                                                              1. Partial stem parasite – E.g: Loranthus.<\/li>\n
                                                              2. Partial root parasite – E.g: Santalum.<\/li>\n<\/ol>\n

                                                                Question 32.
                                                                \nDefine Amensalism.
                                                                \nAnswer:
                                                                \nAmensalism is an interspecific interaction in which one species is inhibited while the other species is neither benefitted nor harmed. The inhibition is achieved by the secretion of certain chemicals called allelopathic substances. Amensalism is also called antibiosis.<\/p>\n

                                                                Question 33.
                                                                \nPoint out any two morphological adaptations noticed in the roots of hydrophytes.
                                                                \nAnswer:<\/p>\n

                                                                  \n
                                                                1. Roots are totally absent in Wolffia and Salvinia or poorly developed in Hydrilla or well developed in Ranunculus.<\/li>\n
                                                                2. The root caps are replaced by root pockets.
                                                                  \nExample: Eichhomia.<\/li>\n<\/ol>\n

                                                                  Question 34.
                                                                  \nWhat are hygrophytes? Give example.
                                                                  \nAnswer:
                                                                  \nThe plants which can grow in moist damp and shady places are called hygrophytes. Examples: Habenaria (Orchid) and Mosses (Bryophytes), etc.<\/p>\n

                                                                  Question 35.
                                                                  \nWhat are trichophyllous plants? Give example.
                                                                  \nAnswer:
                                                                  \nIn xerophytic plants, with the leaves and stem are covered with hairs are called trichophyllous plants.
                                                                  \nExample: Cucurbits (Melothria and Mukia)<\/p>\n

                                                                  Question 36.
                                                                  \nGive an example for following type of adaptations.<\/p>\n

                                                                    \n
                                                                  1. Phyllode<\/li>\n
                                                                  2. Cladode<\/li>\n<\/ol>\n

                                                                    Answer:<\/p>\n

                                                                      \n
                                                                    1. Phyllode – E.g: Acacia.<\/li>\n
                                                                    2. Cladode – E.g: Asparagus.<\/li>\n<\/ol>\n

                                                                      Question 37.
                                                                      \nWrite a brief note on pneumatophores. Give an example.
                                                                      \nAnswer:
                                                                      \nPneumatophores are the special type of negatively geotropic roots developed by halophytes. It possess pneumathodes to get sufficient aeration. They are also called breathing roots.
                                                                      \nExample: Avicennia.<\/p>\n

                                                                      3 – Mark Questions<\/span><\/p>\n

                                                                      Question 38.
                                                                      \nDifferentiate habitat from niche.
                                                                      \nAnswer:
                                                                      \nHabitat:<\/p>\n

                                                                        \n
                                                                      1. A specific physical space occupied by an organism (species).<\/li>\n
                                                                      2. Same habitat may be shared by many organisms (species).<\/li>\n
                                                                      3. Habitat specificity is exhibited by organism.<\/li>\n<\/ol>\n

                                                                        Niche:<\/p>\n

                                                                          \n
                                                                        1. A functional space occupied by an organism in the same eco-system.<\/li>\n
                                                                        2. A single niche is occupied by a single species.<\/li>\n
                                                                        3. Organisms may change their niche with time and season.<\/li>\n<\/ol>\n

                                                                          Question 39.
                                                                          \nWhat is thermal stratification? Explain its types.
                                                                          \nAnswer:
                                                                          \nThermal stratification is usually found in aquatic habitat. The change in the temperature profile with increasing depth in a water body is called thermal stratification. There are three kinds of thermal stratifications.<\/p>\n

                                                                            \n
                                                                          1. Epilimnion – The upper layer of warmer water.<\/li>\n
                                                                          2. Metalimnion – The middle layer with a zone of gradual decrease in temperature.<\/li>\n
                                                                          3. Hypolimnion – The bottom layer of colder water.<\/li>\n<\/ol>\n

                                                                            Question 40.
                                                                            \nWhat are the adverse effects of temperature on plant?
                                                                            \nAnswer:<\/p>\n

                                                                              \n
                                                                            1. Temperature affects the enzymatic action of all the bio-chemical reactions in a plant body.<\/li>\n
                                                                            2. Low temperature with high humidity can spread diseases to plants.<\/li>\n
                                                                            3. The varying temperature with moisture determines the distribution of the vegetation types.<\/li>\n<\/ol>\n

                                                                              Question 41.
                                                                              \nExplain briefly about the three types of fire.
                                                                              \nAnswer:<\/p>\n

                                                                                \n
                                                                              1. Ground fire – Which is flameless and subterranean.<\/li>\n
                                                                              2. Surface fire – Which consumes the herbs and shrubs.<\/li>\n
                                                                              3. Crown fire – Which bums the forest canopy.<\/li>\n<\/ol>\n

                                                                                Question 42.
                                                                                \nClassify soil based on its formation.
                                                                                \nAnswer:
                                                                                \nBased on soil formation (pedogenesis), the soils are divided into:<\/p>\n

                                                                                  \n
                                                                                1. Residual soils -These are soils formed by weathering and pedogenesis of the rock.<\/li>\n
                                                                                2. Transported soils – These are transported by various agencies.<\/li>\n<\/ol>\n

                                                                                  Question 43.
                                                                                  \nLoamy soil is ideal for crop cultivation – Justify.
                                                                                  \nAnswer:
                                                                                  \nLoamy soil is ideal soil for cultivation, since it consists of 70% sand and 30% clay or silt or both. It ensures good retention and proper drainage of water. The porosity of soil provides adequate aeration and allows the penetration of roots.<\/p>\n

                                                                                  Question 44.
                                                                                  \nDirection of mountain determines the richness of vegetation – Justify.
                                                                                  \nAnswer:
                                                                                  \nNorth and south faces of mountain or hill possess different types of flora and fauna because they differ in their humidity, rainfall, light intensity, light duration and temperature regions. The two faces of the mountain or hill receive different amount of solar radiation, wind action and rain. Of these two faces, the windward region possesses good vegetation due to heavy rains and die leeward region possesses poor vegetation due to rain shadows (rain deficit).<\/p>\n

                                                                                  Question 45.
                                                                                  \nWhat are epiphytes? Explain their characteristic features.
                                                                                  \nAnswer:
                                                                                  \nThe plants which are found growing on other plants without harming them are called epiphytes. They are commonly found in tropical rain forest The epiphytic higher plant (Orchids) gets its nutrients and water from the atmosphere with the help of their hygroscopic roots which contain special type of spongy tissue called Velamen. So it prepares its own food and does not depend on the host. They use the host plant only for support and does not harm.<\/p>\n

                                                                                  Question 46.
                                                                                  \nDiscuss on predator – prey interaction with example.
                                                                                  \nAnswer:
                                                                                  \nPredation: It is an interaction between two species, one of which captures, kills and eats up the other. The species which kills is called a predator and the species which is killed is called a prey. The predator is benefitted while the prey is harmed. Many herbivores are predators. Cattles, Camels and Goats etc., frequently browse on the tender shoots of herbs, shrubs and trees.<\/p>\n

                                                                                  Question 47.
                                                                                  \nGive an account of Mimicry.
                                                                                  \nAnswer:
                                                                                  \nMimicry is a phenomenon in which living organism modifies its form, appearance, structure or behavior and looks like another living organism as a self defence and increases the chance of their survival. Floral mimicry is for usually inviting pollinators but animal mimicry is often protective. Mimicry is a result of evolutionary significance due to shape and sudden heritable mutation and preservation of natural selection.<\/p>\n

                                                                                  Question 48.
                                                                                  \nMention any two species that exhibits protective mimicry.
                                                                                  \nAnswer:<\/p>\n

                                                                                    \n
                                                                                  1. Carausium morosus (Stick insect)<\/li>\n
                                                                                  2. PhyIlium frondosum (Leaf insect).<\/li>\n<\/ol>\n

                                                                                    Question 49.
                                                                                    \nWhat is co-evolution? Explain with example.
                                                                                    \nAnswer:
                                                                                    \nThe interaction between organisms, when continues for generations, involves reciprocal changes in genetic and morphological characters of both organisms. This type of evolution is called Co-evolution. It is a kind of co-adaptation and mutual change among interactive species.
                                                                                    \nExamples:<\/p>\n

                                                                                      \n
                                                                                    • Corolla length and proboscis length of butterflies and moths (Habenaria and Moth).<\/li>\n
                                                                                    • Bird\u2019s beak shape and flower shape and size.<\/li>\n<\/ul>\n

                                                                                      Question 50.
                                                                                      \nHow physical dryness differ from physiological dryness?
                                                                                      \nAnswer:<\/p>\n

                                                                                        \n
                                                                                      1. Physical dryness: In these habitats, soil has a little amount of water due to the inability of the soil to hold water because of low rainfall.<\/li>\n
                                                                                      2. Physiological dryness: In these habitats, water is sufficiently present but plants are unable to absorb it because of the absence of capillary spaces.
                                                                                        \nExample: Plants in salty and acidic soil.<\/li>\n<\/ol>\n

                                                                                        Question 51.
                                                                                        \nPoint out the Anatomical adaptations exhibited by the Halophytes.
                                                                                        \nAnswer:
                                                                                        \nAnatomical adaptations:<\/p>\n

                                                                                          \n
                                                                                        1. Epidermal cells of stem is heavily cutinized, almost squarish and are filled with oil and tannins.<\/li>\n
                                                                                        2. Star\u2019 shaped sclereids and \u2018H\u2019 shaped heavy thickened spicules that provide mechanical strength to cortex are present in the stem.<\/li>\n
                                                                                        3. The leaves may be dorsiventral or isobilateral with salt secreting glands.<\/li>\n<\/ol>\n

                                                                                          5-Mark Question<\/span><\/p>\n

                                                                                          Question 52.
                                                                                          \nExplain various edaphic factors that affect vegetation.
                                                                                          \nAnswer:
                                                                                          \nThe important edaphic factors which affect vegetation are as follows:<\/p>\n

                                                                                            \n
                                                                                          1. Soil moisture: Plants absorbs rain water and moisture directly from the air.<\/li>\n
                                                                                          2. Soil water: Soil water is more important than any other ecological factors affecting the distribution of plants. Rain is the main source of soil water. Capillary water held between pore spaces of soil particles and angles between them is the most important form of water available to the plants.<\/li>\n
                                                                                          3. Soil reactions: Soil may be acidic or alkaline or neutral in their reaction. pH value of the . soil solution determines the availability of plant nutrients. The best pH range of the soil for cultivation of crop plants is 5.5 to 6.8.<\/li>\n
                                                                                          4. Soil nutrients: Soil fertility and productivity is the ability of soil to provide all essential plant nutrients such as minerals and organic nutrients in the form of ions.<\/li>\n
                                                                                          5. Soil temperature: Soil temperature of an area plays an’important role in determining the
                                                                                            \ngeographical distribution of plants. Low temperature reduces use of water and solute absorption by roots. .<\/li>\n
                                                                                          6. Soil atmosphere: The spaces left between soil particles are called pore spaces which contains oxygen and carbon-di-oxide.<\/li>\n
                                                                                          7. Soil organisms: Many organisms existing in the soil like bacteria, fungi, algae, protozoans, nematodes, insects and earthworms, etc. are called soil organisms.<\/li>\n<\/ol>\n

                                                                                            Question 53.
                                                                                            \nWhat does competition refers to? Classify and describe it.
                                                                                            \nAnswer:
                                                                                            \n1.Competition: It is an interaction between two organisms or species in which both the organisms or species are harmed. Competition is the severest in population that has irregular distribution. Competition is classified into intraspecific and interspecific.<\/p>\n

                                                                                            2. Intraspecific competition: It is an interaction between individuals of the same species. This competition is very severe because all the members of species have similar requirements of food, habitat and pollination etc., and they also have similar adaptations to fulfill their needs.<\/p>\n

                                                                                            3. Interspecific competition: It is an interaction between individuals of different species. In grassland, many species of grasses grow well as there is little competition when enough nutrients and water is available. During drought Shortage of water occurs. A life and death competition starts among the different species of grass lands.<\/p>\n

                                                                                            Survival in both these competitions is determined by the quantity of nutrients, availability of water and migration to new areas. Different species of herbivores, larvae and grass hopper competing for fodder or forage plants. Trees, shrubs and herbs in a forest struggle for sunlight, water and nutrients and also for pollination and dispersal of fruits and seeds, The Utricularia (Bladderwort) competes with tiny fishes for small crustaceans and insects.<\/p>\n

                                                                                            Question 54.
                                                                                            \nPoint out any five morphological adaptations of epiphytes.
                                                                                            \nAnswer:
                                                                                            \nMorphological adaptations:<\/p>\n

                                                                                              \n
                                                                                            1. Root system is extensively developed. These roots may be of two types. They are Clinging roots and Aerial roots. Clinging roots fix the epiphytes firmly on the surface of the supporting objects. Aerial roots are green coloured roots which may hang downwardly and absorb moisture from the atmosphere with the help of a spongy tissue called velamen.<\/li>\n
                                                                                            2. Stem of some epiphytes are succulent and develop pseudo bulb or tuber.<\/li>\n
                                                                                            3. Generally the leaves are lesser in number and may be fleshy and leathery.<\/li>\n
                                                                                            4. Myrmecophily is a common occurrence in the epiphytic vegetation to prevent the predators.<\/li>\n
                                                                                            5. The fruits and seeds are very small and usually dispersed by wind, insects and birds.<\/li>\n<\/ol>\n

                                                                                              Higher Order Thinking Skills (HOTs) Questions<\/span><\/p>\n

                                                                                              Question 1.
                                                                                              \nBeing a tropical country, India is the largest producer of delicious mangoes. These mango tree don\u2019t grow in temperate countries. Give reason.
                                                                                              \nAnswer:
                                                                                              \nMango tree show very narrow range of thermal tolerance. Hence they cannot grow in temperate countries.<\/p>\n

                                                                                              Question 2.
                                                                                              \nWhat is cause of flag forms in trees?
                                                                                              \nAnswer:
                                                                                              \nUnidirectional wind stimulates the development of flag forms in trees.<\/p>\n

                                                                                              Question 3.
                                                                                              \nIn the picture given below, A and B represents the two different biomes. What does the letter C denotes? What will be its impact on the organisms in C Explain with example.
                                                                                              \nAnswer:
                                                                                              \n\"Samacheer
                                                                                              \nThe letter C denotes Ecotone – a transition zone between two different ecosystem. Those species found in the ecotone will have impact of environment of two habitats.
                                                                                              \nE.g. Owl in the ecotone area between forest and grassland.<\/p>\n

                                                                                              Question 4.
                                                                                              \nObserve the tabular column and complete it using proper terms.
                                                                                              \n\"Samacheer
                                                                                              \nAnswer:
                                                                                              \nA = +
                                                                                              \nB = Commensalism
                                                                                              \nC = –
                                                                                              \nD = Parasitism
                                                                                              \nE = –<\/p>\n

                                                                                              The data given about Chapterwise Samacheer Kalvi Class 12th Bio Botany Solutions Chapter 6 Principles of Ecology Questions and Answers will help the students to score good marks in the exam. Contact us for more updated information and also to clear your queries. Keep every single update by bookmarking our website. Get advanced skills by referring to Samacheer Kalvi Class 12th Bio Botany Solutions Chapter 6 Principles of Ecology solutions pdf.<\/p>\n","protected":false},"excerpt":{"rendered":"

                                                                                              Are you searching for the Tamilnadu State Board Class 12th Bio Botany Solutions Chapter 6 Principles of Ecology Questions and Answers. Then, you are at the correct place. Verify all the Bio Botany Solutions subject concepts and begin your practice for the exam. Every concept in Samacheer Kalvi 12th Bio Botany Book Solutions Chapter 6 […]<\/p>\n","protected":false},"author":3,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"spay_email":"","footnotes":""},"categories":[8],"tags":[],"blocksy_meta":"","jetpack_featured_media_url":"","_links":{"self":[{"href":"https:\/\/samacheerguru.com\/wp-json\/wp\/v2\/posts\/12479"}],"collection":[{"href":"https:\/\/samacheerguru.com\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/samacheerguru.com\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/samacheerguru.com\/wp-json\/wp\/v2\/users\/3"}],"replies":[{"embeddable":true,"href":"https:\/\/samacheerguru.com\/wp-json\/wp\/v2\/comments?post=12479"}],"version-history":[{"count":1,"href":"https:\/\/samacheerguru.com\/wp-json\/wp\/v2\/posts\/12479\/revisions"}],"predecessor-version":[{"id":56074,"href":"https:\/\/samacheerguru.com\/wp-json\/wp\/v2\/posts\/12479\/revisions\/56074"}],"wp:attachment":[{"href":"https:\/\/samacheerguru.com\/wp-json\/wp\/v2\/media?parent=12479"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/samacheerguru.com\/wp-json\/wp\/v2\/categories?post=12479"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/samacheerguru.com\/wp-json\/wp\/v2\/tags?post=12479"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}