जीव विज्ञान - कक्षा 12: जीवों में जनन (Reproduction in Organisms)

Is chapter mein hum jeevon ke janan ke prakar aur prakriya ko samjhenge. Janan (reproduction) ek moolbhoot prakriya hai jisse jeev apni aane wali peedhi ko janm dete hain. Yeh notes NCERT textbook par aadharit hain aur examination ke liye upyogi hain.

Mukhya Bindu (Key Points)

• Janan ke do mukhya prakar: Laingik (sexual) aur Alaiangik (asexual)
• Alaiangik janan ke prakar: khandan (fission), mukulan (budding), beejanu (spores) aadi
• Laingik janan mein nishwachan (gamete formation) aur garbhadhan (fertilization) shamil hai
• Prakriti me vibhinn jeev alag-alag janan vidhiyan apnate hain

Here we have provided NCERT notes for Class 12 जीवand विज्ञान in hindi Language, Just select the chapters below to get notes of the same:

जीवों मैं जनन

पुष्पीय पादपों में लैंगिंक जनन

मानव जनन

जनन स्वास्थ्य

वंशागति तथा विविधता के सिद्धांत

वंशागति का आणविक आधार

विकास

मानव स्वास्थ और रोग

खाध उत्पादन में वृद्धि कार्यनीति

मानव कल्याण में सूक्ष्मजीव

जैव प्रोधोगिकीand सिद्धान्त एवं प्रक्रम

जैव प्रोधोगिकी एवं उसके उपयोग

जीव और समष्टिया

पारितंत्र या पारिस्थितिक तंत्र

जैव विविधता व संरक्षण

पर्यावरण के मुद्दे

Alaiangik Janan (Asexual Reproduction)

Alaiangik janan mein keval ek janak (parent) hota hai aur isme gamete nahi bante. Is prakar ke janan se utpann santati aapas mein aur janak se anuvanshiki roop se samaan (identical) hoti hai. Kuch pramukh vidhiyan hain:

1. Khandan (Fission)

Isme jeev do ya adhik bhagon mein bat jata hai. Jaise- द्विखंडन (Binary fission) - Amoeba aur Paramecium mein hota hai. बहुखंडन (Multiple fission) - Plasmodium mein hota hai.

2. Mukulan (Budding)

Janak jeev ke sharir par ek chota sa udbhed (bud) banta hai jo bad mein alag ho jata hai aur naya jeev banta hai. Jaise- Hydra, yeast.

3. Beejanu Nirmaan (Spore Formation)

Kai fungi aur algae beejanu (spores) banaate hain jo pratikul paristhitiyon mein lambi samay tak jeevit rah sakte hain. Jaise- Rhizopus (bread mould).

4. Pravridhi (Regeneration)

Kuch prani apne shareer ke kate hue bhagon se naya poora jeev bana lete hain. Jaise- Planaria, starfish.

5. Kalika Janan (Vegetative Propagation)

Paudhon mein jad, tana ya patti se naya paudha banta hai. Jaise- aalu (tuber), pyaaz (bulb), ganna (stem cutting).

Laingik Janan (Sexual Reproduction)

Isme do janak (father aur mother) ki aavashyakta hoti hai. Dono apne-apne gametes (nishwachan) banaate hain jo garbhadhan ke baad zygote mein badalte hain. Zygote se embryo aur phir naya jeev viksit hota hai. Is prakar ke janan se anuvanshiki vividhata (genetic variation) aati hai jo evolution ke liye jaroori hai.

Laingik Janan ke Charan (Stages)

• Yughanak Nirmaan (Gametogenesis): Male gamete (shukranu) aur female gamete (andaan) ka nirmaan.
• Garbhadhan (Fertilization): Shukranu aur andaan ka milan. Yeh either bahya (external) - jaise meinak, mendak, ya antah (internal) - jaise manushya, pakshi mein hota hai.
• Bhruun Vikas (Embryogenesis): Zygote se embryo ka vikas aur phir bachche ka janm.

Laingik Janan ke Prakaar

Kuch jeev eklingi (monoecious/unisexual) hote hain - jaise manushya, jahan nar aur madah alag hain. Kuch jeev hermafrodit (bisexual) hote hain - jaise kenchua (earthworm), jisme nar aur madah dono ang ek hi jeev mein hote hain.

Mahatvpurn Paribhashayein (Important Definitions)

• जीवनकाल (Life span): Jeev ke janm se lekar mrityu tak ka samay.
• जनन क्षमता (Reproductive capacity): Jeev kitni santati utpann kar sakta hai.
• क्लोन (Clones): Alaiangik janan se bane anuvanshiki roop se ek samaan jeev.
• Meiosis: Vahan prakar ka koshika vibhajan jo gametes banane ke liye hota hai, jisme kromosom sankhya aadhi ho jati hai.

Chart: Alaiangik vs Laingik Janan

Alaiangik	Laingik
Ek janak	Do janak
Gamete nahi bante	Gamete bante hain
Santati ek jaise (identical)	Santati mein vividhata (variation)
Tej aur saral	Dheema aur jateel

Yeh notes aapko NCERT Class 12 Biology ke 'Reproduction in Organisms' chapter ko samajhne mein madad karenge. Exam ke liye important points yaad rakhein aur diagrams practice karein.