Exploring Our Environment

InthisarticleTheLifeSciencesPlantsPartsofaPlantFunctionsoftheLeafSo,Howdoplantsgrow?TheLifeSciences:Asweallknowthereisagreatvarietyoflivingthingsaroundus.Manslifelargelydependsonthem.Lifeonearthcannotexistwithouttheseplants&animals.Letstakeasanexample,ahugetree(sayaBanyanTree).Weobserveanumberoftinyplantsgrowingunderitsshade.Similarlytherearedifferentvarietiesofanimals-alluniqueinsizeandshape.But,whatiscommontoallofthem?Althoughtheylookdifferentfromoneanother,theyshareanumberoffeatures.Alllivingthingsgrow,change,move,needfood,feel,respondtochangesaroundthem,breatheandreproduce.Youwillfindbelowanexplanationoftheabovementionedlines.Livingthingsgrowandchange:Whenseedsaresown,theygrowintoplants.Similarly,BudschangeintoflowersandPupsgrowintodogs.Livingthingsmove:Sinceplantsmaketheirownfood,theydonothavetomove,butanimalsmoveinsearchoffoodusingtheirlegs,finsandwings-whateverthecasemaybe.Livingthingsneedfood:Energyisimportantforalllivingthings.Bothanimalsandplantsgetenergyfromfood.Livingthingsfeelandrespondtochangesaroundthem:Plantsnormallygrowtowardsthedirectionoflightandwarmth.TheleavesofthePitcherplantandTouchMeNotcanrespondtosomethingtouchingthem.Animalshavesenseorganslikeeyes,ears,nosesandtheskin,whichhelpthemrespondtochanges.Livingthingsbreatheandreproduce:Plantshavesmallholesintheirleaves,(calledstomata),throughwhichtheybreathe.Animalsbreathethroughanorgancalledthenosewhileinsectslikecockroachesbreathethroughsmallholes.Plantsproducenewoffspringfromtheirstems,leavesorseedswhilebirdslayeggsandanimalsgivebirthtoyoungones.Plants:Plantsaresaidtobethemostusefulgiftsofnaturetoman.Theplantkingdomcomprisesofabout260,000knownspeciesofwoodyplants,bushes,vinesandtrees..Mostplantsaregreenbecausetheycontainasubstancecalledchlorophyll.Itisasubstancethattapstheenergy(ofsunlight)whichplantsneedtomaketheirownfood.Plantsareanchoredinagrowingmediumsuchassoil.Mostplantshaveroots,stem,leaves,flowersandfruits,althoughtheremightbeexceptions.Therootoftheplantremainsunderthegroundwhiletheotherpartsoftheplantwhichremainabovethegroundareknownasshoots.Givenbelowisalistofthecommonpartsofaplantandtheirfunctions.Theflowerontheleftillustratesthevariouspartsoftheplant.PartsofaPlant:TheRoot:Rootsofplantsareof2types:Taproots:Amainthickrootextendsfromthestemandmanybranchesgrowoutfromit.e.g.Mustard,Beans.Fibrousroots:Theydonothaveamainrootbutanumberofrootsareattachedtotheendofthestem.e.g.Rice,Onions.FunctionsoftheRoot:Rootsfixtheplantfirmlyinthesoil.Rootsabsorbthewaterandmineralsfromthesoil.TheStem:Itgivessupporttotheplant.Leaves,branches,buds,flowersandfruitsgrowonit.FunctionsoftheStem:Thewatertakenbytherootoftheplanttravelsthroughthestem.Thiswaterisusedtomakefoodwhichisrequiredbyallpartsoftheplant.TheLeaf:Theleafisanimportantpartoftheplant,whichmakesitsownfood.Theflatpartofaleafiscalledtheleafblade.Themainveinandsideveincanbeseenontheleafblade.FunctionsoftheLeafTheleafhelpstheplanttobreathe.Thewateriscarriedthroughtheveinstotheleaf.Theleafbladehastinyholesontheundersidecalledstomata.Theleaftakesinairthroughtheseholesandgivesoutexcesswater.Theleafgetsitsgreencolorfromasubstancecalledchlorophyll.Itmakesfoodfortheplantusingsunlight,agaspresentinaircalledcarbondioxide,chlorophyllandwater.Whilemakingfood,theleavestakeincarbondioxideandgiveoutoxygen.Foodisstoredinsomeleaves.Clickhereforanafter-schoolexercise.Flowers,fruitsandseeds:Flowershelpaplanttoreproduce.Theymaketheplantlookbeautifulandgivesweetsmell.Differenttypesoffruitsgrowfromflowers.Seedsarepresentinsidethefruits.So,Howdoplantsgrow?Aplantproducesmanyseedsbutonlyfewofthemareabletoproducemoreplants.Aseedhasaseedcoat,seedleavesandababyplantisinsideit,thedevelopmentofaseedintoseedlingiscalledgermination.Airwaterandwarmthareneededforgermination.Seedsarescatteredordispersedsothattheygetfavorableconditionstogrow,dispersalagentsarewater,windandanimals.Aplantcanreproducefromleaves,stemcuttingsandundergroundpartsetc.

The Life Sciences:

As we all know there is a great variety of living things around us. Man's life largely depends on them. Life on earth cannot exist without these plants & animals.

Lets take as an example, a huge tree (say a 'Banyan Tree'). We observe a number of tiny plants growing under its shade. Similarly there are different varieties of animals-all unique in size and shape. But, what is common to all of them? Although they look different from one another, they share a number of features. All living things grow, change, move, need food, feel, respond to changes around them, breathe and reproduce.

You will find below an explanation of the above mentioned lines.

Living things grow and change: When seeds are sown , they grow into plants. Similarly, Buds change into flowers and Pups grow into dogs.

Living things move: Since plants make their own food, they do not have to move, but animals move in search of food using their legs, fins and wings- whatever the case may be.

Living things need food: Energy is important for all living things. Both animals and plants get energy from food.

Living things feel and respond to changes around them: Plants normally grow towards the direction of light and warmth. The leaves of the 'Pitcher plant' and 'Touch Me Not' can respond to something touching them. Animals have sense organs like eyes, ears, noses and the skin, which help them respond to changes.

Living things breathe and reproduce: Plants have small holes in their leaves, (called stomata), through which they breathe. Animals breathe through an organ called the nose while insects like cockroaches breathe through small holes. Plants produce new offspring from their stems, leaves or seeds while birds lay eggs and animals give birth to young ones.

Plants:

Plants are said to be the most useful gifts of nature to man. The plant kingdom comprises of about 260,000 known species of woody plants, bushes, vines and trees. . Most plants are green because they contain a substance called chlorophyll. It is a substance that taps the energy (of sunlight) which plants need to make their own food. Plants are anchored in a growing medium such as soil.

Most plants have roots, stem, leaves, flowers and fruits, although there might be exceptions. The root of the plant remains under the ground while the other parts of the plant which remain above the ground are known as shoots.

Given below is a list of the common parts of a plant and their functions. The flower on the left illustrates the various parts of the plant.

Parts of a Plant:

The Root: Roots of plants are of 2 types: Taproots: A main thick root extends from the stem and many branches grow out from it. e.g. Mustard, Beans. Fibrous roots: They do not have a main root but a number of roots are attached to the end of the stem. e.g. Rice, Onions.

Functions of the Root: Roots fix the plant firmly in the soil. Roots absorb the water and minerals from the soil.

The Stem: It gives support to the plant. Leaves, branches, buds, flowers and fruits grow on it.

Functions of the Stem: The water taken by the root of the plant travels through the stem. This water is used to make food which is required by all parts of the plant.

The Leaf: The leaf is an important part of the plant, which makes its own food .The flat part of a leaf is called the leaf blade. The main vein and side vein can be seen on the leaf blade.

Functions of the Leaf

The leaf helps the plant to breathe. The water is carried through the veins to the leaf. The leaf blade has tiny holes on the underside called stomata. The leaf takes in air through these holes and gives out excess water.

The leaf gets its green color from a substance called chlorophyll. It makes food for the plant using sunlight, a gas present in air called carbon dioxide, chlorophyll and water.

Food is stored in some leaves.

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Flowers, fruits and seeds: Flowers help a plant to reproduce. They make the plant look beautiful and give sweet smell. Different types of fruits grow from flowers. Seeds are present inside the fruits.

So, How do plants grow?

A plant produces many seeds but only few of them are able to produce more plants. A seed has a seed coat, seed leaves and a baby plant is inside it, the development of a seed into seed ling is called germination. Air water and warmth are needed for germination. Seeds are scattered or dispersed so that they get favorable conditions to grow, dispersal agents are water, wind and animals. A plant can reproduce from leaves, stem cuttings and underground parts etc.