The Living World | Free NEET Notes in Hinglish | Class 11
1. Understanding the Amazing Variety of Living Organisms
Jab tum apne aas-paas dekhte ho, toh tumhe bohot saare living beings dikhai denge — jaise chhote potted plants, aas-paas udte hue insects, aasman me udte birds, tumhare pet animals, aur alag-alag tarah ke trees ya animals.
Inke alawa, bohot saare chhote organisms bhi hote hain jo itne microscopic hote hain ki hamari aankhon se dikhai nahi dete, lekin phir bhi hamare aas-paas exist karte hain — jaise bacteria aur dusre microbes. ✅
Ab agar tum thoda bada area observe karoge, toh tumhe aur bhi zyada variety of organisms dikhai degi.
For example, agar tum kisi dense forest me jaate ho, toh wahan tumhe bohot saare naye plants, animals aur insects milenge jo shayad tumne pehle kabhi nahi dekhe honge.
Ye clearly show karta hai ki life bohot saari different forms aur types me exist karti hai.
Har alag type ka living being, chahe wo plant ho, animal ho ya koi chhota organism, usse species kaha jaata hai.
Scientists ab tak lagbhag 1.7 se 1.8 million species discover aur describe kar chuke hain.
Zameen par maujood itne saare alag-alag living organisms ki variety ko biodiversity kaha jaata hai.
Jaise-jaise hum naye ya purane places ka study aur exploration karte jaate hain, hume nayi-nayi species milti rehti hain.
Isliye, known organisms ki total number time ke saath badhti ja rahi hai.
✅ Key Terms:
- Biodiversity – Zameen par paaye jaane wale living organisms ki variety aur total number ko biodiversity kehte hain.
- Species – Ek khaas type ka living organism ko species kehte hain.
2. Scientific Naming of Living Organisms (Nomenclature)
Duniya bhar me millions of different plants aur animals paaye jaate hain.
Hamare local area me, hum in organisms ko unki local names se jaante hain, lekin ye names alag-alag regions me different hote hain — kabhi-kabhi ek hi country ke andar bhi.
Ab socho agar alag-alag jagah ke log ek hi animal ya plant ke baare me baat karte, lekin alag-alag names use karte, toh kitni confusion hoti! 😅
Sabko ek dusre ko samajhna bohot mushkil ho jaata.
Isliye, hume ek standard system ki zarurat hai jisse har living organism ko ek fixed name mil sake, jo poore duniya me same ho.
Is process ko nomenclature kehte hain.
Lekin name dene se pehle, hume organism ko properly identify aur describe karna padta hai.
Is process ko identification kehte hain — yani exactly pata karna ki organism kya hai.
Naming process ko easy aur uniform banane ke liye, scientists ne rules aur procedures banaye hain jisse har known organism ko scientific name assign kiya ja sake.
Ye names poore world ke scientists ke liye accepted hote hain.
- Plants ke liye: Naming rules follow ki jaati hain International Code for Botanical Nomenclature (ICBN) ke according.
- Animals ke liye: Naming rules follow ki jaati hain International Code of Zoological Nomenclature (ICZN) ke according.
Scientific names ka purpose ye hai:
- Har organism ko sirf ek unique name milta hai.
- Ye name poore duniya me recognized hota hai.
- Koi bhi do organisms same scientific name share nahi karte.
- Duniya ke kisi bhi hisse ka insaan is name ko use karke organism ko sahi tarah se identify kar sakta hai.
✅ Key Concepts:
Nomenclature – Kisi organism ko standard scientific name dena.
Identification – Organism ko sahi tarah se pehchanna aur describe karna.
ICBN – Plants ke naming rules.
ICZN – Animals ke naming rules.
🔹 Binomial Nomenclature – Scientific Naming System
Duniya bhar ke biologists living organisms ko scientifically name dene ke liye universal rules follow karte hain.
Har scientific name me do main parts hote hain:
- Genus name
- Species name (isko specific epithet bhi kehte hain)
Is do-part naming method ko Binomial Nomenclature kehte hain.
Ye system scientist Carolus Linnaeus ne develop kiya tha, aur ab poori duniya me use hota hai.
Ye format bohot useful aur easy to use hai.
For example, mango ka scientific name hai Mangifera indica.
- Yahan Mangifera → Genus
- indica → Species (specific epithet)
✅ Universal Rules of Scientific Naming:
Scientific names hamesha Latin me hote hain ya fir unhe Latin jaisa dikhaya jaata hai, chahe organism kahin se bhi aaye.
- Pehla word → Genus
- Doosra word → Species
Writing rules:
- Haath se likhte waqt: Dono words ko alag-alag underline karna chahiye.
- Typing me: Dono words ko italics me likhte hain (ctrl + I), taaki unka Latin origin dikh sake.
- Genus name capital letter se start hota hai, aur species name small letter se.
Example: Mangifera indica
- Species name ke baad author ka short form likha jaata hai, jo pehli baar us species ko describe kiya tha.
Example: Mangifera indica Linn.
Iska matlab hai ki Linnaeus ne pehli baar is species ko describe aur name diya tha.
✅ Key Terms:
Binomial Nomenclature – Scientific naming ka do-word system.
Genus – Related organisms ka bigger group.
Specific epithet – Genus ke andar unique species.
Linnaeus – Modern taxonomy ke father, jinhone ye naming system banaya.
🔹 Classification, Taxonomy & Systematics
Zameen par millions of living organisms hain, isliye har ek ko individually study karna almost impossible hai.
Isliye scientists ek method use karte hain jise classification kehte hain.
Classification ka matlab hai living organisms ko alag-alag categories me group karna, based on easily seen features — jaise unka appearance, behavior, ya type.
For example, hum naturally cheezon ko plants, animals, dogs, cats, ya insects me divide karte hain.
Jab tum “dog” sunte ho, tum cat ka imagine nahi karte — kyunki tumhara dimaag kuch features ko “dog” se connect kar leta hai.
Aur agar koi kahe “Alsatian”, toh hum sab jaante hain ki ye dog ka ek type hai.
Similarly, agar hum “mammal” kehte hain, hum turant sochte hain animals jinke body me hair ho aur external ears ho.
Plants me agar koi kahe “wheat”, toh tum wheat plant imagine karoge — rice ya sugarcane nahi.
Toh ye groups jaise dogs, mammals, wheat, plants, animals helpful categories hain jo life ko study karna easy banati hain.
Scientific terms me, ye groups ko taxa (singular: taxon) kehte hain.
Yaad rahe — taxa alag-alag levels me exist karte hain:
- Dog → ek taxon
- Mammal → ek bada group jo dogs include karta hai
- Animal → aur bhi bada group jo saare mammals include karta hai
Ye method jisme organisms ko features ke basis pe group kiya jaata hai, usse taxonomy kehte hain.
Modern taxonomy sirf outer appearance pe depend nahi karti. Ye include karti hai:
- Internal structures (jaise organs)
- Cell structure
- Organism ka development
- Uska habitat aur ecological role
Isliye taxonomy me 4 main steps hote hain:
- Characterisation – Organism ke features ka study karna
- Identification – Exact pata lagana ki organism kya hai
- Classification – Organism ko ek category (taxon) me group karna
- Nomenclature – Organism ko proper scientific name dena
🧠 What is Systematics ?
Humans hamesha se alag-alag organisms ko samajhne ki koshish karte rahe hain — especially wo organisms jo food, clothing, ya shelter ke kaam aate hain.
Ancient times me, organisms ko iske usefulness ke basis pe group kiya jaata tha.
Lekin dheere-dheere, scientists ka interest sirf grouping me nahi raha, balki ye samajhne me bhi lag gaya ki organisms ek dusre se kaise related hain.
Isse ek broader field ka janm hua, jise systematics kehte hain.
Systematics word Latin se aaya hai — “systema”, matlab systematic arrangement.
Ye term pehli baar Carolus Linnaeus ne use kiya, jinhone Systema Naturae naam ki kitab likhi.
Aaj, systematics me ye include hota hai:
- Identification
- Nomenclature
- Classification
Aur saath hi, ye evolutionary relationships ka bhi study karta hai — yani ki organisms evolution ke through kitne closely related hain.
✅ Key Concepts:
Classification – Organisms ko features ke basis pe group karna.
Taxa – Scientific categories jaise species, genus, etc.
Taxonomy – Organisms ko classify aur name karne ki science.
Systematics – Classification ka study + organisms ke evolutionary relationships ka study.
3. Hierarchy of Taxonomic Ranks in Living Organisms
Living organisms ki classification ek hi step me nahi hoti — ye multiple levels ya ranks ke through hoti hai.
Har step ya level ko taxonomic category kehte hain, aur ye saari categories milke taxonomic hierarchy banati hain.
Har category classification ka ek unit hoti hai, matlab ye classification system me ek specific position ya rank rakhti hai. Is unit ko taxon (plural: taxa) kehte hain.
Example se samjhte hain:
Insects ko lo — inme kuch common features hote hain, jaise 3 pairs of jointed legs.
Is similarity ki wajah se, insects ko same group ya category me rakha jaata hai.
Toh “insects” sirf ek general group nahi hai — ye classification system me proper taxonomic rank hold karta hai.
Tum aur aise groups ke baare me soch sakte ho? Jaise birds, mammals, grasses etc. — ye sab categories based on shared features hain.
Aur inme se har ek taxon hai, jo overall classification structure ka part hai.
Ye categories (jaise species, genus, family etc.) sirf appearance (morphology) pe nahi based hain, balki ye biological groups hain jinka real scientific meaning hai.
🧬 Main Taxonomic Categories (Ranks) in Order:
- Kingdom
- Phylum (used for animals) / Division (used for plants)
- Class
- Order
- Family
- Genus
- Species
Har living organism — chahe wo plant ho ya animal — ko species level tak classify kiya jaata hai, jo sabse lowest aur most specific rank hai.
🤔 How do we decide which organism goes in which category ?
Ek organism ko sahi tarah se classify karne ke liye, hume uske features ya characters ke baare me pata hona chahiye.
Ye include karte hain:
- Uska body structure (internal aur external)
- Uska functioning
- Uska reproduction ka tareeka
- Aur dusre organisms se comparison
Ye sab scientists ko help karta hai similarities aur differences find karne me, aur organism ko sahi taxonomic ranks me place karne me.
✅ Key Points:
- Taxonomic Category – Classification ka har level (jaise genus ya species).
- Taxon – Kisi bhi rank ka group (jaise mammals, birds etc.).
- Taxonomic Hierarchy – Kingdom se species tak arranged categories ka complete system.
- Species – Sabse chhota aur most specific group.
- Characteristics ka knowledge correct classification ke liye essential hai.
3.1 Species
Taxonomy (classification ki science) me, species ek aisa group hai jisme organisms apne main features me bohot similar hote hain.
Members of a species:
- Common characteristics share karte hain (appearance, behavior, etc.)
- Dusre closely related species se clearly distinguishable hote hain
Examples:
- Mango → Mangifera indica
- Potato → Solanum tuberosum
- Lion → Panthera leo
In names me:
- Pehla word (Mangifera, Solanum, Panthera) → Genus
- Doosra word (indica, tuberosum, leo) → Species / specific epithet
Har genus me ek ya zyada species ho sakti hain, jo appearance me related hain lekin different enough hain alag species maanne ke liye.
Example:
- Genus Panthera me:
- Panthera leo (lion)
- Panthera tigris (tiger)
- Genus Solanum me:
- Solanum tuberosum (potato)
- Solanum nigrum (black nightshade)
- Solanum melongena (brinjal/eggplant)
Similarly, humans species sapiens me aate hain aur genus Homo me.
Toh humans ka scientific name hai: Homo sapiens
✅ Key Concepts:
Species – Aise organisms ka group jo similar traits share karte hain.
Specific epithet – Scientific name ka doosra word, jo species ko identify karta hai.
Genus – Species se higher rank, jo similar species ko ek saath group karta hai.
Scientific Name – Hamesha do parts me likha jaata hai: Genus + Species (e.g., Homo sapiens).
3.2 Genus
Genus ek aisa group hai jisme closely related species hoti hain — yani wo species jisme bohot saare common features hote hain.
Simple words me:
- Same genus ke species ek dusre se zyada look aur behave alike karte hain
- Aur inke beech similarities different genera ke species se zyada hoti hain
Examples se samjhte hain:
- Potato (Solanum tuberosum) aur Brinjal (Solanum melongena) → alag species hain, lekin dono same genus Solanum me aate hain kyunki unke similar features hain.
- Lion (Panthera leo), Leopard (Panthera pardus), aur Tiger (Panthera tigris) → alag species hain, lekin same genus Panthera me aate hain kyunki unme strong bodies, sharp teeth, aur carnivorous nature jaise common features hain.
Lekin ye genus Panthera dusre genus Felis se alag hai, jisme domestic cats aur chhote wild cats aate hain.
Yadi general sense me sab cats hain, fir bhi Panthera aur Felis alag genera me rakhe gaye hain structural aur behavioral differences ki wajah se.
✅ Key Concepts:
Genus – Aise species ka group jo closely related ho.
Same genus ke species ek dusre ke saath zyada features share karte hain.
Example:
- Panthera leo (lion), Panthera tigris (tiger), Panthera pardus (leopard) → Same genus: Panthera
- Felis catus (domestic cat) → Different genus: Felis
3.3 Family
Family – Genus se higher taxonomic category hai.
Ye un related genera ka group hai jo kuch common features share karte hain, lekin species ya genus level ke comparison me similarities kam hoti hain.
Short me:
Species → Genus → Family
Families broader groups hain, jo similar genera se bante hain.
🪴 In Plants:
Families ko classify karne ke liye vegetative features (jaise leaves aur stems) aur reproductive features (jaise flowers aur fruits) dono use kiye jaate hain.
Example:
- Genera Solanum (potato, brinjal),
- Petunia (flowering plant), aur
- Datura (thorn apple)
Ye sab family Solanaceae me aate hain, kyunki inme similar floral aur structural characteristics hain
🐾 In Animals:
Genus Panthera (lion, tiger, leopard) aur genus Felis (domestic cats) ko same family – Felidae me rakha gaya hai, kyunki inme common features hain jaise body structure, sharp teeth, aur carnivorous diet.
Ab cats aur dogs ko lo — dono me kuch similarities hain (four legs, tails, sharp teeth), lekin major differences bhi hain.
Isliye, ye alag families me rakhe gaye:
- Cats → Family Felidae
- Dogs → Family Canidae
✅ Key Points:
- Family – Related genera ka group.
- Family me similarities genus ya species ke comparison me kam hoti hain.
- Plants me families ko leaves, flowers, fruits ke structure ke basis pe group kiya jaata hai.
- Animals me families ko body structure, behavior, aur habits ke basis pe group kiya jaata hai.
3.4 Order
Taxonomic hierarchy me Family ke upar ek category hoti hai — Order.
Ye un related families ka group hai jo kuch common characteristics share karte hain.
Species, genus, aur family ke comparison me — jahan grouping me bohot close similarities hoti hain — order me families ko group kiya jaata hai, jinme kam features common hote hain, lekin kuch key similarities phir bhi hoti hain.
Toh, jaise-jaise hum higher levels me jaate hain (order, class, etc.), organisms ko group karne ke liye kam characteristics share karna sufficient hota hai.
🪴 In Plants:
Families jaise Solanaceae (potato, tomato, brinjal) aur Convolvulaceae (sweet potato, morning glory) ko Order Polymoniales me rakha gaya hai, mainly kyunki inme similar floral structures hain — jaise flower arrangement aur reproductive parts.
🐾 In Animals:
Order Carnivora me ye families aati hain:
- Felidae (cats, lions, tigers)
- Canidae (dogs, wolves, foxes)
Ye families same order me isliye rakhi gayi hain kyunki ye sab meat-eating mammals hain aur inme special adaptations hain jaise sharp teeth aur claws hunting ke liye.
✅ Key Points:
Order – Related families ka group.
Order me similarities genus ya family ke comparison me kam hoti hain.
Grouping aksar important structural ya functional traits ke basis pe hoti hai.
Examples:
- Plant Order: Polymoniales (includes Solanaceae, Convolvulaceae)
- Animal Order: Carnivora (includes Felidae, Canidae)
3.5 Class
Class – Ek higher taxonomic category hai jo related orders ka group include karti hai.
Ye Order ke upar aur Phylum/Division ke neeche aati hai taxonomic hierarchy me.
Jab multiple orders me kuch common features hote hain, toh unhe ek class me group kiya jaata hai.
🐾 Example from Animals:
Order Primata me animals jaise monkeys, gorillas, gibbons aate hain.
Order Carnivora me tigers, cats, dogs aate hain.
Ye dono orders Class Mammalia me group kiye gaye hain kyunki inme kuch key features common hain:
- Mammary glands present hain jo young ones ko feed karte hain
- Hair ya fur body pe hoti hai
- External ears hote hain
- Giving birth to young ones (zyadatar cases me)
Class Mammalia me bohot saare aur orders bhi aate hain jo ye characteristics share karte hain.
Toh, chahe monkeys aur tigers kaafi different animals hain, phir bhi same class me rakhe gaye hain kyunki ye fundamental features common to all mammals share karte hain.
✅ Key Points:
Class – Ek category jo multiple related orders include karti hai.
Orders in a class basic structural aur functional traits share karte hain.
Example:
Class Mammalia includes:
- Order Primata (monkeys, gorillas)
- Order Carnivora (tigers, cats, dogs)
- Aur other mammalian orders
3.6 Phylum (Animals) / Division (Plants)
Jab hum related classes of animals ko group karte hain, toh unhe ek higher category – Phylum me rakha jaata hai.
Ye animals ke classification system ke top levels me se ek hai.
🐾 In Animals:
For example, animals jaise:
- Fishes
- Amphibians (like frogs)
- Reptiles (like snakes, lizards)
- Birds
- Mammals
Ye sab alag-alag classes me aate hain, lekin inme kuch common features hain:
- Notochord present hai (development ke time ek rod-like supporting structure)
- Dorsal hollow nerve cord present hai (nervous system ka part)
In shared features ki wajah se, ye sab Phylum Chordata me rakhe gaye hain.
Toh, Phylum Chordata me sab animals with backbone ya similar internal structure aate hain, chahe ye bahar se kaafi different dikhte ho. ✅
🌿 In Plants:
Plants me Phylum word use nahi hota; uske equivalent category ko Division kehte hain.
Example:
Alag-alag classes of plants (jaise ferns, flowering plants, etc.) ko Divisions me group kiya jaata hai, based on similarities jaise reproduction method, vascular tissues, etc.
✅ Key Points:
Phylum (animals) – Related classes ka group jo kuch fundamental similarities share karte hain.
Division (plants) – Phylum jaisa hi, lekin plant classes ko group karne ke liye use hota hai.
Example (Animals):
- Phylum Chordata includes fishes, amphibians, reptiles, birds, mammals
- Basis of grouping: Presence of notochord, dorsal nerve cord, etc.
3.7 Kingdom – Highest Level of Biological Classification
Biological classification system me, sabse highest taxonomic category ko Kingdom kehte hain.
Ye ek bada group hota hai jisme organisms hote hain jo sirf kuch common features share karte hain.
🐾 Kingdom Animalia:
Sabhi animals — chahe wo insects, fishes, reptiles, birds, ya mammals ho — alag-alag phyla me aate hain, lekin inhe ek hi kingdom – Animalia me group kiya gaya hai.
Ye kingdom include karta hai sabhi multicellular, eukaryotic, heterotrophic organisms jo move karte hain aur food consume karte hain.
🌿 Kingdom Plantae:
Dusri taraf, alag-alag divisions ke plants ko Kingdom Plantae me group kiya gaya hai.
Ye usually multicellular, photosynthetic, aur non-motile organisms hote hain.
Aage se, hum in dono major groups ko Plant Kingdom aur Animal Kingdom ke naam se commonly refer karte hain.
🔼 Taxonomic Hierarchy – From Species to Kingdom
Sabhi taxonomic categories — species se leke kingdom tak — ascending order me arranged hain:
👉 Species → Genus → Family → Order → Class → Phylum/Division → Kingdom
- Jaise-jaise hum hierarchy me upar jaate hain (Kingdom ki taraf), common features kam ho jaate hain.
- Neeche jaane par, category me organisms zyada similar characteristics share karte hain.
Isliye:
- Species → sabse specific category
- Kingdom → sabse broadest category
Higher levels me, jaise kingdom, exact relationships identify karna mushkil ho jaata hai, kyunki organisms ek dusre se kaafi different hote hain
🧠 Sub-categories in Classification:
Classification ko aur accurate banane ke liye, scientists ne sub-categories create kiye hain, jaise:
- Subspecies
- Subclass
- Suborder, etc.
Ye sub-categories help karte hain organisms ko zyada precise aur scientific tarike se hierarchy me place karne me
📊 Examples of Classification
| Organism | Genus | Family | Order | Class | Phylum/Division | Kingdom |
|---|---|---|---|---|---|---|
| Human | Homo | Hominidae | Primata | Mammalia | Chordata | Animalia |
| Housefly | Musca | Muscidae | Diptera | Insecta | Arthropoda | Animalia |
| Mango | Mangifera | Anacardiaceae | Sapindales | Dicotyledonae | Angiospermae | Plantae |
| Wheat | Triticum | Poaceae | Poales | Monocotyledonae | Angiospermae | Plantae |
✅ Key Concepts Recap:
Kingdom – Sabse broadest taxonomic category.
Animalia – Sabhi animals.
Plantae – Sabhi plants.
Taxonomic Hierarchy – Specific (species) se general (kingdom) tak.
- Upar jaane par → similarities decrease
- Neeche jaane par → similarities increase
4. Summary – The Living World
Hamare aas-paas ki duniya me bohot saari variety ke living organisms hain — chhote microscopic forms se leke bade animals aur plants tak. Scientists ne millions of species discover aur name kar liye hain, lekin bohot saare abhi bhi undiscovered hain.
Size, shape, color, habitat, aur functions me itni wide diversity hone ki wajah se, ye samajhna zaroori hai ki kya cheez “living” hai aur hum in organisms ko kaise group aur name kar sakte hain.
Itni badi variety ka study aasaan banane ke liye, biologists ne ek system develop kiya hai:
- Identify organisms
- Name them correctly
- Classify them into groups based on similarities and differences
Ye scientific system of naming aur grouping ko taxonomy kehte hain.
Taxonomy kaafi useful hai agriculture, forestry, industry me, aur hume biological resources aur biodiversity ko samajhne me help karta hai.
Sabhi organisms ko proper scientific name diya jaata hai, jo global rules (jaise ICBN aur ICZN) pe based hota hai. Ye names binomial nomenclature system pe based hote hain, jisme har name ke do parts hote hain — genus aur species.
Har organism ko specific level me place kiya jaata hai classification system me. Ye levels ko taxonomic categories ya taxa kehte hain, aur saath me ye taxonomic hierarchy banate hain — species (most specific) se kingdom (most general) tak.
✅ Key Concepts Recap:
The living world me bohot saare diverse organisms hote hain.
Taxonomy hume help karta hai organisms ko identify, name, aur classify karne me.
Binomial nomenclature har organism ko do-part scientific name deta hai.
Organisms ko levels me arrange kiya jaata hai:
Species → Genus → Family → Order → Class → Phylum/Division → Kingdom
Ye system scientific study, conservation, aur biodiversity ke use me kaafi useful hai.
