UPSC Darpan

BiologyPushan · Class 9-10

Trophic level, 10% ka niyam aur zeher ka ulta safar

Neha ke papa ne gaon ke khet par keede maarne ki dawa chhidki thi. Kuch hafton baad gaon ke vigyan shikshak ne bataya ki sabse zyada zeher us chidiya ke sharir mein mila jo khet se door ped par rehti thi. Neha hairaan thi: zeher us tak pahuncha kaise — aur itna zyada kyun?

Socho pehle… phir dekho jawab

Neha ne khet ki taraf dekha — ghaas, tidde, mendak, aur ped par chidiya. Usne kaha, 'Khaane ki kadi se! Ghaas par thoda zeher, phir tidde ne bahut ghaas khaayi, phir mendak ne bahut tidde, phir chidiya ne bahut mendak — har kadam par zeher jama hota gaya.' Shikshak ne joda, 'Urja ghat-ti hai, par na tootne wala zeher badhta hai.'

Shikshak Neha ko khet ki med par le gaye aur kadi ke star ginaaye. 'Trophic level (poshan star): pehla star utpaadak (paudhe), doosra shakahari, teesra maansahari, chautha upar ke maansahari.' Neha ne ghaas ko pehla star aur tidde ko doosra likha. Phir unhone gire hue patton ke neeche mitti dikhayi: 'Apghatak har star ke mare jeev tod kar poshak tatva mitti aur paani mein lautate hain — isliye padarth (carbon, nitrogen) chakra mein ghoomta hai, par urja ek disha mein behti hai.'

'Toh urja kitni aage jaati hai?' Neha ne poocha. Shikshak bole, '10% ka niyam: ek trophic level ki urja ka lagbhag 10% hi agle level ke sharir mein jama hota hai; baaki saans, garmi aur mal mein nikal jaata hai.' Neha ne copy mein hisaab likha: 1,000 J ghaas ki urja → 100 J tidde mein → 10 J mendak mein → 1 J saanp mein. 'Isiliye kadi 4-5 star se lambi nahi hoti aur upar ke jeev kam hote hain,' shikshak ne kaha.

Ab zeher ki baari thi. Shikshak ne naya shabd sikhaya: biomagnification (jaiv-aavardhan). 'Kuch rasayan — jaise purana keetnashak DDT — sharir mein toot-te nahi aur nikal nahi paate. Har level kai neeche wale jeev khaata hai, isliye zeher har kadam par gadha hota jaata hai.' Neha samajh gayi: upar ke jeev — shikari chidiya, bade jeev, aur hum — mein sabse zyada. 'Isliye keetnashak ka chhidkaav mitti ki baat nahi, poore jaal ki baat hai.'

Neha ne apni kadi soch board par likhi: khet par DDT, phir paani mein, phir chhote jeevon mein, phir unhe khaane walon mein, isliye door baithi chidiya ke ande kamzor. Shaam ko usne papa se baat ki, aur dono ne milkar faisla kiya ki keetnashak ki jagah pehle mendak aur chidiya ginenge — 'pehle dekhein, jaal khud kitna sambhal raha hai.'

Raat ko dadi ne Neha ki baat suni aur ek purani pankti yaad dilayi. Taittiriya Upanishad (3.2) kehta hai 'annad dhyeva khalvimani bhutani jayante' — sab jeev anna se janmte hain, anna se jeete hain, anna mein lautte hain. Dadi boli, 'Hazaaron saal pehle kaha gaya yeh vaakya aaj ke poshan-chakra ki hi baat hai: ek vyakhya yahi hai.'

Neha ab har chhidkaav se pehle sochti hai. Tum Neha hoti toh gaon ke doosre kisaanon ko jaal ki yeh baat kaise samjhaati?

Humne kya kiya :- Chidiya tak zeher ka raasta kadi ke har star par urja aur zeher ka hisaab lagakar samjha.

Isse kya hua :- Saaf hua ki urja upar jaate hue ghat-ti hai (10%), par na tootne wala zeher badhta hai — isliye jaal ke upar wale jeev sabse pehle sanket dete hain.

Ghar pe try karo

Ek khet ka food web banao aur har jeev ke paas 'urja' likho: ghaas 10,000 J, tidda 1,000 J, mendak 100 J, saanp 10 J. Phir ek doosre rang se 'zeher' likho jo har kadam par 10 guna gadha ho. Dono teer ulte kyun hain? Ek para likho.

Wow!

DDT ka asar is kadar upar pahuncha ki kai shikari chidiyon ke ande itne patle ho gaye ki ghosle mein hi toot jaate the — zeher chhidka khet par tha, nuksaan aasmaan mein hua!

3 sawaal

  1. 10% ke niyam ke anusaar ek trophic level se agle tak kitni urja pahunchti hai?
    Jawab dekho

    Lagbhag 10%. Baaki saans, garmi aur mal mein kharch ho jaati hai; isliye kadi chhoti aur upar ke jeev kam.

  2. Biomagnification mein zeher sabse zyada kis level mein milta hai?
    Jawab dekho

    Sabse upar ke upbhokta. Na tootne wale rasayan har kadam par gadhe hote jaate hain; upar ke jeev kai neeche wale khaate hain.

  3. Ecosystem mein urja aur padarth mein kya farak hai?
    Jawab dekho

    Urja ek disha mein behti hai, padarth chakra mein ghoomta hai. Apghatak poshak tatva wapas lautate hain (chakra), par urja har star par garmi ban kar nikal jaati hai.

NCERT se jodo: NCERT Class 10 Science — hamara paryavaran: food chain, trophic level, 10% niyam, biological magnification (idea in words)

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