Biological Classification: Class 11 Biology Chapter 2 Hinglish mein

Kisi sabzi mandi mein ghoom kar dekho, har jagah sorting dikhegi: hari pattedaar sabziyan ek dher mein, lauki-tori doosre mein, pyaaz aur aloo peeche sookhe mein rakhe hue. Yeh grouping bechne wale aur khaana banane wale ke kaam ki hai, biologist ke nahi. Hazaron saal tak log living things ko isi tarah sort karte rahe, is hisaab se ki woh humein khaana, ghar ya kapde dete hain, us se bahut pehle ki kisi ne poocha ho ki organisms bane kaise hain ya ek doosre se kaise related hain.

Two kingdoms se five tak

Ancient Greece mein Aristotle ne sabse pehle life ko uske use ke bajaay uske apne features se sort karne ki koshish ki. Plants ko unhone unke overall form ke hisaab se trees, shrubs ya herbs kaha; animals ko is aadhaar par baanta ki unmein red blood hai ya nahi. Dono simple morphological characters hain: bahari form ke aise features jo organism ko kaate bina dikh jaate hain.

Lagbhag do hazaar saal baad, Linnaeus ke time mein, naturalists ne two-kingdom system apnaya: har organism ya to plant (Plantae) tha ya animal (Animalia). Ise padhana aasaan tha, lekin isne aise organisms ko ek saath daal diya jo buniyaadi taur par alag hain. Bina true nucleus wale cells, nucleus wale cells ke saath baithe the; single cells, many-celled bodies ke saath; aur photosynthesis karne wali green algae un fungi ke saath ek kingdom mein thi jo photosynthesis nahi kar sakti. Bahut se organisms dono mein se kisi box mein theek se fit nahi hote the (Fig. 2.1).

Two kingdoms se three, phir four aur aakhir mein five bane, jab biologists ne un characters par dhyaan dena shuru kiya jo naked eye se nahi dikhte: cell kaise bana hai, uski wall kis cheez ki hai, organism khaana kaise leta hai, kahan rehta hai, reproduce kaise karta hai aur kiska descendant hai. Har revision mein Plantae aur Animalia kingdoms bane rahe, haalaanki plant ya animal kise maana jaaye yeh badalta raha; sabse zyada badlaav baaki kingdoms ki sankhya aur nature mein hua.

1969 mein American ecologist R.H. Whittaker ne five-kingdom classification propose kiya: Monera, Protista, Fungi, Plantae aur Animalia. Unhone organisms ko paanch criteria se sort kiya:

• cell structure: prokaryotic ya eukaryotic;
• body organisation: single cells, loose tissue, ya tissues aur organs;
• mode of nutrition: khud khaana banana (autotrophic) ya bana-banaya khaana lena (heterotrophic);
• reproduction;
• phylogenetic relationships, yaani evolutionary ancestry.

Poocho ki mushroom, moss aur bacterium mein kya common hai, to purana jawaab tha: cell wall. Sirf isi ek shared character ki wajah se flowering plants, gymnosperms, ferns aur mosses ko fungi, blue-green algae aur bacteria ke saath 'plants' maana gaya. Dhyaan se dekho to yeh group teen tarah se bikhar jaata hai:

• Nucleus: bacteria aur blue-green algae prokaryotes hain, jinmein true nucleus nahi hota; group ke baaki sab eukaryote hain.
• Cells ki sankhya: single-celled algae, many-celled algae ke saath rakhi gayi thi.
• Khaana aur walls: fungi bana-banaya khaana absorb karte hain aur chitin ki walls banate hain; green plants apna khaana khud banate hain aur cellulose ki walls banate hain.

Whittaker ka jawaab tha har tarah ke organisation ko apna alag kingdom dena: har prokaryote ke liye Monera, chitin-walled absorbers ke liye Fungi aur single-celled eukaryotes ke liye Protista, aur many-celled producers aur consumers ke liye Plantae aur Animalia. Iska ek side effect students ko hairaan karta hai. Wall wale, photosynthetic single cells jo pehle algae mein the, ab Protista mein bina wall wale, khaana nigalne wale cells jaise Amoeba ke saath hain, jinhe pehle animals kaha jaata tha. Organisms nahi badle the; rules badle the.

Koi bhi classification final nahi hota. Har naya tool, electron microscope se lekar DNA sequencing tak, aise characters dikhata hai jo lines ko dobara kheench sakte hain, aur aaj ka lakshya ek phylogenetic system hai, jo life ke asli branching history ko dikhaye, sirf shared structure, physiology aur reproduction ko nahi. Aisa hi ek redraw, three-domain system, Monera ko do domains mein baantata hai aur saare eukaryotes ko teesre mein rakhta hai, jisse kul chhe kingdoms bante hain.11Domains Bacteria, Archaea aur Eukarya 1990 mein Carl Woese aur unke saathiyon ne propose kiye the. Inse tum aage ki classes mein miloge; yeh book Whittaker ko follow karti hai. Yeh chapter Monera, Protista aur Fungi ko detail mein padhata hai aur Plantae aur Animalia ki ek jhalak deta hai, jinhe Chapters 3 aur 4 cover karte hain.

Whittaker ke criteria ko ek chhoti key mein badla ja sakta hai, yes-or-no questions ki ek chain jo kisi ek kingdom par khatam hoti hai (Fig. 2.2). Table 2.1 wahi characters ek saath dikhata hai.

2.1 Kingdom Monera

Garden ki upjaau mitti ka ek gram uthao, aur ho sakta hai tumhare haath mein kai crore bacteria hon. Yeh Earth par sabse zyada paaye jaane wale organisms hain aur Monera ke akele members hain. Bahut kam jagah inke liye zyada kathor hain: hot springs, namak ke khet, deserts, polar snow aur deep sea floor, sab jagah bacteria milte hain, aur kai tarah ke bacteria plants aur animals ke upar ya andar rehte hain, kuch bina nuksaan ke aur kuch parasites ki tarah.

Microscope mein bacteria ke chaar basic shapes dikhte hain (Fig. 2.3): gol (coccus, plural cocci), rod jaise (bacillus, plural bacilli), comma jaise (vibrio) aur spiral (spirillum, plural spirilla).22NCERT comma wale form ka singular vibrium aur plural vibrio likhti hai; zyaadatar microbiology books ek cell ko vibrio aur kai cells ko vibrios kehti hain. Kisi anjaan bacterium ke baare mein microbiologist sabse pehle jo cheezein note karta hai, unmein shape ek hai.

Simple bodies ke andar kamaal ki chemistry chhupi hai. Bacteria sunlight par, inorganic chemicals par ya lagbhag kisi bhi organic khaane par jee sakte hain; kisi aur group mein itni wide metabolic diversity nahi dikhti. Autotrophic bacteria inorganic raw materials se apna khaana banate hain, light ki energy se (photosynthetic autotrophs) ya chemical reactions ki energy se (chemosynthetic autotrophs). Lekin zyaadatar bacteria heterotrophs hain jo doosre organisms, zinda ya mare hue, ke banaye khaane par jeete hain.

2.1.1 Archaebacteria

Archaebacteria ki mazbooti ka raaz unki cell wall hai, jo kisi bhi doosre bacterium jaisi nahi hai, aur iski wajah se woh aisi jagahon par bas paate hain jahan zyaadatar cells mar jaayein (Fig. 2.4). Har group ka naam uski extreme jagah par hai: brine mein halophiles ('namak pasand'), garam, acidic springs mein thermoacidophiles ('garmi aur acid pasand'), aur daldali keechad mein methanogens ('methane banane wale').

Methanogens cows aur buffaloes jaise ruminants ke gut mein bhi rehte hain. Kyunki in animals ka gobar unhe saath le aata hai, band tank mein ferment hone ke liye chhoda gaya gobar biogas chhodta hai, ek fuel jo zyaadatar methane hota hai.

2.1.2 Eubacteria

Baaki hazaron tarah ke bacteria eubacteria hain, yaani 'true bacteria'. Har cell ke chaaron taraf ek rigid cell wall hoti hai, aur jo tairte hain unhe ek flagellum chalata hai.

Eubacteria mein cyanobacteria (blue-green algae) plants ke sabse kareeb hain: yeh chlorophyll a se photosynthesis karte hain, wahi pigment jo green plants use karte hain. Yeh jahan bhi geela ya nam ho wahan milte hain, ponds mein, samudra mein aur nam mitti par, single cells ke roop mein, gelatinous sheath mein bandhi colonies ke roop mein, ya filaments ke roop mein. Kuch filamentous kinds, jaise Nostoc aur Anabaena, khaas thick-walled cells mein atmospheric nitrogen bhi fix karte hain jinhe heterocysts kehte hain (Fig. 2.5). Jab kisi pond ya lake mein sewage ya fertiliser runoff mil jaata hai, to cyanobacteria badh kar ek ghana hara bloom bana sakte hain.

Kuch eubacteria poore andhere mein khaana banate hain. Yeh chemosynthetic autotrophs ammonia aur nitrite jaise inorganic substances ko oxidise karke energy lete hain, aur us energy ko ATP ke roop mein store karte hain. Is process mein woh nitrogen, phosphorus, iron aur sulphur jaise nutrients ko ecosystems mein recycle karne mein madad karte hain.

Heterotrophic bacteria baaki sab se sankhya mein zyada hain. Inke bina sookhi pattiyan aur mare hue sharir jama hote jaate, kyunki zyaadatar decomposers (saprophytes) hain jo mare hue matter mein band minerals ko mitti mein wapas lautate hain. Hamari zindagi inse judi hai: rasoi ka dahi, kai antibiotics aur chana aur moong ki roots par nitrogen-fixing nodules, sab inka kaam hai. Kuch pathogens bhi hain. Logon mein cholera, typhoid aur tetanus, aur nimbu aur santre ke baagon mein citrus canker bacterial diseases hain, aur kuch species fasalon, farm animals aur pets par bhi hamla karti hain.

Bacterium ke badhne ka aam tareeka fission hai: woh apna DNA copy karta hai, bada hota hai aur do daughter cells mein toot jaata hai (Fig. 2.6); ideal conditions mein kuch kinds har lagbhag 20 minute mein divide hote hain. Mushkil samay mein response alag hota hai, aur kai bacteria resistant spores banate hain. Bacteria ek primitive tarah ka sexual reproduction bhi dikhate hain, jismein DNA ek bacterium se doosre mein jaata hai.

Mycoplasmas ke naam bacteria mein do records hain: inmein cell wall bilkul nahi hoti, aur yeh sabse chhote known living cells hain. Yeh oxygen ke bina jee sakte hain, aur kai plants aur animals ke pathogens hain.

2.2 Kingdom Protista

Protista un eukaryotes ka kingdom hai jo kabhi single cell se aage nahi badhe. Iski seemaon par behes hoti hai (kya ek photosynthetic one-celled alga protist hai ya plant? biologists ek mat nahi hain), isliye books mein isme shaamil cheezein alag hoti hain. Yahan ismein paanch groups hain, zyaadatar aquatic: chrysophytes, dinoflagellates, euglenoids, slime moulds aur protozoans.

Andar se protist ek poora eukaryotic cell hai, jismein membrane se ghira nucleus aur doosre membrane-bound organelles hote hain. Kai flagella ya cilia se tairte hain. Asexual reproduction ke alaawa, protists sexually bhi reproduce karte hain jab do cells fuse hokar zygote banate hain. Kuch plant jaise, kuch animal jaise aur kuch fungus jaise dikhte hain, isliye Protista ko aksar in teen kingdoms ke beech ki kadi kaha jaata hai.

2.2.1 Chrysophytes

Har pond aur ocean mein aise anginat microscopic organisms behte rehte hain jo current ke khilaaf tair nahi sakte: yeh plankton hain. Inmein se kai chrysophytes hain, ek group jismein diatoms aur golden algae (desmids) aate hain.33Aaj zyaadatar phycologists desmids ko green algae mein rakhte hain; exams ke liye NCERT ki grouping follow karo. Chrysophytes meethe paani aur samudra dono mein rehte hain, aur zyaadatar photosynthesis karte hain. Diatoms bahut zaroori hain: yeh oceans ke chief producers hain, woh aadhaar jis par marine life ka bada hissa tika hai.

Diatom ek kaanch jaise dabbe mein rehta hai. Iski wall do patle halves ki hoti hai, ek thoda bada, jo dabbe aur dhakkan ki tarah overlap karte hain (Fig. 2.7). Walls mein silica bhara hota hai, isliye woh sadti nahi. Laakhon saalon mein mare hue diatoms ke shells lake aur sea floor par mote deposits ke roop mein jama ho gaye hain jinhe diatomaceous earth kehte hain, ek khurdura powder jo polishing aur oils aur syrups ko filter karne mein use hota hai.

2.2.2 Dinoflagellates

Kabhi-kabhi coastal samudra ka ek hissa laal ho jaata hai. Iska kaaran hai red tide: Gonyaulax jaise red dinoflagellates itni tezi se badhte hain ki paani rang jaata hai, aur itni maatra mein toxins chhodte hain ki fish aur doosre marine animals mar jaate hain.

Dinoflagellates zyaadatar marine, photosynthetic protists hain jinka rang, yellow, green, brown, blue ya red, unke main pigments par depend karta hai. Wall ki bahari surface par sakht cellulose plates kavach ki tarah hoti hain. Zyaadatar mein do flagella hote hain: ek plates ke beech ek groove mein cell ke aar-paar rehta hai, aur doosra uski lambai ke saath chalta hai (Fig. 2.8).

2.2.3 Euglenoids

Euglena wale pond ke paani ka jar ek andhere cupboard mein rakh do, phir bhi cells bhookhe nahi marte. Euglenoids sunlight mein photosynthesis karte hain, lekin light na mile to heterotrophic feeding par switch kar jaate hain aur chhote organisms ka shikaar karte hain (Fig. 2.9). Hairaani ki baat yeh hai ki inke pigments higher plants jaise hi hote hain. Zyaadatar euglenoids ruke hue meethe paani mein rehte hain. Inmein cell wall nahi hoti; ek protein-rich layer, pellicle, body ko flexible rakhti hai, aur har cell mein do flagella hote hain, ek chhota aur ek lamba.

2.2.4 Slime Moulds

Jungle ki geeli zameen par tumhe kisi sadte hue lakdi ke tukde par rengti ek chipchipi peeli parat mil sakti hai: yeh slime mould hai, saprophytic protists mein se ek. Yeh sadti tehniyon aur pattiyon ke organic matter ko nigal kar khaata hai. Jab tak khaana aur nami rehti hai, cells ikattha hokar ek plasmodium banate hain, ek mass jo kai feet tak fail sakta hai (Fig. 2.10). Jab conditions kharab hoti hain, plasmodium khud ko fruiting bodies mein badal leta hai jinke siron par spores hote hain. Spores ki true walls hoti hain aur woh behad resistant hote hain, kai saalon tak zinda rehte hain, aur hawa ke current unhe door le jaate hain.

2.2.5 Protozoans

Protozoans animal jaise protists hain, jinhe animals ke primitive rishtedaar maana jaata hai. Inmein se har ek heterotroph hai, jo predator ki tarah shikaar karta hai ya parasite ki tarah rehta hai. Biologists chaar major groups maante hain (Fig. 2.11):

• Amoeboid protozoans (meetha paani, samudra ka paani, nam mitti) pseudopodia, yaani 'false feet', bahar nikalte hain, rengne ke liye bhi aur prey ko gherne ke liye bhi; Amoeba iska classic example hai. Marine species silica shells rakhti hain, aur Entamoeba insaan ke gut mein parasite ki tarah rehta hai.
• Flagellated protozoans flagella hila kar tairte hain. Kuch free-living hote hain; parasitic waalon mein Trypanosoma hai, jo tsetse fly se failta hai aur sleeping sickness karta hai.
• Paramoecium jaise ciliated protozoans hazaron cilia se dhake hote hain aur tezi se tairte hain. Cilia ki coordinated lehrein paani ko, aur usmein maujood khaane ko, gullet mein dhakelti hain, jo cell surface par khulne wali ek cavity hai.
• Sporozoans ek infectious, spore jaisi stage se guzarte hain. Sabse badnaam Plasmodium hai: female Anopheles mosquitoes se failne wala yeh malaria karta hai, jo aaj bhi har saal laakhon logon ki jaan leta hai.

2.3 Kingdom Fungi

Monsoon mein bread ka ek slice ya kata hua amrood bahar chhod do, aur kuch hi dinon mein us par rui jaisi parat aa jaati hai: yeh fungus hai. Fungi heterotrophs ka ek kingdom hai jo hairaan karne wale shapes aur jagahon mein milte hain. Kuch humein khaana dete hain ya hamare kaam aate hain: market ke mushrooms, yeast (ek single-celled fungus) jo bread ka aata phulata hai aur beer ferment karta hai, aur Penicillium, jo antibiotics ka source hai. Kuch dushman hain: toadstools khaane laayak nahi hote, ek parasitic fungus sarson ki pattiyon par safed dhabbe karta hai, aur Puccinia gehun ka rust disease karta hai.

Fungal spores hawa aur paani ke saath udte hain aur mitti, plants aur animals par baith jaate hain, isliye fungi cosmopolitan hain. Garmi aur nami inhe sabse zyada pasand hai. Isi wajah se monsoon mein leather ke joote par fungus lag jaata hai, aur refrigerator khaane ko thanda rakh kar fungi aur bacteria se uske kharab hone ko dheema karta hai.

Hand lens se is rui ko dekho to tumhe threads dikhenge. Har thread ek hypha hai, aur hyphae ka uljha hua network mycelium hai (Fig. 2.12); sirf yeasts is pattern ko todte hain kyunki woh single cells ki tarah rehte hain. Hyphae do design ke hote hain. Coenocytic hyphae lagaataar tubes hote hain jinke cytoplasm mein kai nuclei bikhre hote hain, jabki septate hyphae mein septa naam ki cross walls tube ko compartments mein baant deti hain. Dono hi tarah se, walls chitin aur doosre polysaccharides se bani hoti hain.

Fungi khaana kabhi ingest nahi karte; woh use absorb karte hain. Zyaadatar giri pattiyon aur sadti lakdi jaise mare hue substrates se soluble organic matter absorb karte hain, isliye saprophytes hain. Parasitic fungi ise zinda plants aur animals se absorb karte hain. Symbiotic fungi ek partner ke saath len-den karte hain: lichen mein ek alga (Lichens), ya mycorrhiza mein kisi higher plant ki roots.

Fungi spores se failte hain, aur spores kai tarah ke hote hain. Asexual spores conidia, sporangiospores ya zoospores hote hain; sexual spores oospores, ascospores ya basidiospores hote hain; aur dono khaas structures, fruiting bodies, ke upar ya andar bante hain. Fungi vegetatively bhi badh sakte hain, fragmentation, fission ya budding se.

Sexual reproduction mein compatible mating types ke do haploid hyphae milte hain aur fuse hote hain. Phir cycle teen steps mein chalta hai (Fig. 2.13):

1. Plasmogamy: do gametes, motile ya non-motile, ka protoplasm fuse hota hai.
2. Karyogamy: unke do nuclei fuse hote hain.
3. Zygote mein meiosis se haploid spores bante hain.

Fungi mein do fusions ke beech ka gap alag hota hai. Agar karyogamy plasmogamy ke turant baad ho, to cells usi waqt diploid (2n) ban jaate hain. Ascomycetes aur basidiomycetes beech mein rukte hain: kuch samay tak har cell mein do alag parental nuclei hote hain, is condition ko dikaryon (n + n) kehte hain, aur life cycle ka yeh hissa dikaryophase hai. Aakhir mein nuclei fuse hote hain, aur fruiting body ke andar meiosis fungus ko wapas haploid spores tak le aata hai.

Teen features kingdom ko classes mein baantte hain: mycelium ka form, spores banne ka tareeka, aur fruiting body ka type. Yahan chaar classes maani gayi hain.

2.3.1 Phycomycetes

Mucor, Rhizopus (upar wali activity ka bread mould) aur Albugo, jo sarson ki pattiyon par safed dhabbe karta hai, phycomycetes hain. Is class ke members paani mein, nam sadti lakdi par, ya plants ke obligate parasites ki tarah rehte hain, aur inka mycelium aseptate aur coenocytic hota hai. Asexual spores ek sporangium ke andar (endogenously) bante hain: ya to zoospores, jo tairte hain, ya aplanospores, jo nahi tair sakte. Do gametes ke sexual fusion se zygospore banta hai; gametes ek jaise (isogamous) ya alag (anisogamous ya oogamous) ho sakte hain.

2.3.2 Ascomycetes

Ascomycetes ka common naam, sac fungi, thaili jaise ascus (plural asci) se aata hai jiske andar inke sexual spores, ascospores, bante hain (endogenously); asci ascocarps naam ki fruiting bodies mein bhare hote hain. Asexually yeh khaas hyphae, conidiophores, par bahar (exogenously) conidia banate hain, aur har conidium germinate hokar naya mycelium bana sakta hai. Mycelium branched aur septate hota hai. Zyaadatar ascomycetes multicellular hote hain, jaise Penicillium, lekin yeast (Saccharomyces) ek single cell hai.

Ascomycetes saprophytes, decomposers ya parasites ki tarah rehte hain, aur kuch coprophilous hain, yaani gobar par ugte hain. Doosre examples hain Aspergillus, Claviceps aur Neurospora, jo geneticists aur biochemists ka pasandida organism hai. Kuch ascomycetes khaas pakwaan hain: morels (Himalayan jungalon ki gucchi) aur truffles bahut mehngi bikti hain.

2.3.3 Basidiomycetes

Har basidiomycete ki pehchaan uska basidium (plural basidia) hai: ek club-shaped cell jismein karyogamy aur meiosis hote hain aur jiske bahar chaar basidiospores bante hain (exogenously). Basidia basidiocarps naam ki fruiting bodies mein grouped hote hain, jaise mushroom ka chhaata. Mushrooms, bracket fungi aur puffballs jaane-pehchaane members hain, jo mitti mein aur lakdi ke tukdon aur ped ke thoontho par ugte hain; rusts aur smuts basidiomycetes hain jo zinda plants ke andar parasites ki tarah rehte hain. Examples: Agaricus (button mushroom), Ustilago (smut) aur Puccinia (rust).

Inka sexual cycle anokha hai: ismein sex organs nahi hote. Plasmogamy tab hoti hai jab alag strains ya genotypes ke do vegetative (somatic) cells fuse hote hain, jisse dikaryotic mycelium banta hai jo aakhir mein basidia banata hai. Asexual spores aam taur par nahi bante, haalaanki branched, septate mycelium aksar fragmentation se badhta hai.

2.3.4 Deuteromycetes

Alternaria, Colletotrichum aur Trichoderma deuteromycetes, yaani imperfect fungi, mein aate hain. 'Imperfect' ka matlab hai ki inki sirf asexual ya vegetative stages hi pata hain: yeh sirf conidia se reproduce karte hain, aur inka mycelium branched aur septate hota hai. Kuch saprophytes hain aur kuch parasites, jabki kai leaf litter ko decompose karke minerals ka cycle chalate rehte hain.

Yeh class asal mein ek holding area hai. Jaise hi kisi member ki sexual ('perfect') stage mil jaati hai, fungus us class mein chala jaata hai jahan woh sach mein aata hai, aksar ascomycetes ya basidiomycetes. Kabhi kisi fungus ki asexual stage ka ek naam tha aur woh yahan rakhi thi, jabki uski sexual stage ka alag naam tha aur woh doosri class mein thi; jab dikhaya gaya ki dono ek hi organism hain, to woh deuteromycetes se bahar ho gaya.

2.4 Kingdom Plantae

Algae, bryophytes, pteridophytes, gymnosperms aur angiosperms milkar Kingdom Plantae banate hain: chlorophyll wale eukaryotes jinhe hum aam taur par plants kehte hain. Plant cells mein saaf dikhne wale chloroplasts hote hain aur walls zyaadatar cellulose ki hoti hain (Chapter 8 cell structure ko detail mein dekhta hai).

Har plant sirf photosynthesis se nahi jeeta. Meghalaya ka pitcher plant Nepenthes khasiana, sundews aur bladderworts jaise insectivorous plants extra nitrogen ke liye chhote animals ko bhi phansate hain, aur Cuscuta (dodder, अमरबेल), jiske peele dhaage jhaadiyon ko dhak lete hain, ek parasite hai jo host plant se apna khaana leta hai. Aise plants partly heterotrophic hote hain.

Plant ka life cycle do generations ke beech badalta rehta hai, is pattern ko alternation of generations kehte hain (Fig. 2.16). Diploid sporophyte meiosis se spores banata hai; har spore badh kar haploid gametophyte banta hai, jo gametes banata hai; gametes fuse hote hain, aur zygote badh kar naya sporophyte banta hai. Har generation kitne samay tak rehti hai, aur woh independent rehti hai ya doosri par depend karti hai, yeh alag-alag plant groups mein alag hai; Chapter 3 inki tulna karta hai.

2.5 Kingdom Animalia

Animal kise kehte hain? Uske khaane se shuru karo. Animals khaana body ke andar lete hain aur use ek internal cavity mein digest karte hain: yeh holozoic nutrition hai. Aakhir mein yeh khaana plants se aata hai, seedhe khaya gaya ho ya food chain ke zariye, aur bacha hua khaana glycogen ya fat ke roop mein store hota hai. Animal bodies multicellular aur eukaryotic hoti hain, aur unke cells mein cell wall nahi hoti.

Zyaadatar animals ek jagah se doosri jagah ja sakte hain, aur zyada complex animals mein vistrit sense organs aur neuromotor (nerve-aur-muscle) systems hote hain. Animal ek nishchit pattern se badh kar nishchit shape aur size ka adult banta hai, jiski shuruaat ek embryo se hoti hai jo sexual reproduction se banta hai, jismein male aur female copulate karte hain. Chapter 4 animal phyla ka survey karta hai.

2.6 Viruses, Viroids, Prions aur Lichens

Whittaker ke five kingdoms mein chaar cheezein chhoot jaati hain jinse tum biology mein baar-baar miloge: lichens, aur teen acellular (non-cellular) agents, viruses, viroids aur prions. Yeh section har ek ka chhota sa parichay deta hai.

Viruses

Cell ke bahar ek virus utna hi zinda hai jitna namak ka ek daana: yeh kuch nahi karta, aur kai viruses ko crystallise kiya ja sakta hai. Kisi suitable host cell ke andar yeh cell ki machinery par kabza kar leta hai, apni copies banata hai aur aam taur par host ko maar deta hai; jab bhi tumhe cold ya flu hua, tumne iska nateeja mehsoos kiya hai. Kyunki viruses cells nahi hain, aur 'living' ka matlab aam taur par 'cells se bana' maana jaata hai, Whittaker ne inhe koi kingdom nahi diya. To kya viruses living hain ya non-living?

Virus shabd Latin ke venom ya zehreele fluid wale shabd se aata hai. Tobacco mosaic disease par experiments ki ek series ne dikhaya ki yeh kis tarah ka agent hai (timeline). Viruses obligate parasites nikle: bahar yeh inert rehte hain, aur sirf kisi khaas host ke living cells ke andar hi badhte hain.

Har virus ek nucleoprotein hai: nucleic acid ka ek core, jo infection failata hai, protein ke ek coat ke andar. Kuch viruses mein nucleic acid RNA hota hai aur kuch mein DNA, lekin dono kabhi nahi, aur virus mein kaun sa hai yeh aksar uske host se juda hota hai (Table 2.5).

Protein coat, yaani capsid, nucleic acid ki raksha karta hai. Yeh capsomeres naam ke kai chhote subunits se banta hai, jo ya to helix ki tarah lage hote hain, jisse tobacco mosaic virus jaisa rod banta hai, ya polyhedron ki tarah, jaise bacteriophage ka kai faces wala head (Fig. 2.18).

Kisi viral disease ka naam lo to tum mumps, smallpox (ab khatam ho chuka), herpes, influenza ya AIDS gina sakte ho. Fasalon mein virus pattiyon se apni pehchaan deta hai: halke aur gaadhe hare rang ka dhabbedaar mosaic, mudti ya lipti pattiyan, peela padna, veins ka feeka padna (vein clearing), aur plants ka bauna aur ruka hua rehna.

Viroids

Socho ek aisa infectious agent jo sirf RNA ka ek chhota strand hai, bilkul bina protein coat ke. Yeh viroid ('virus jaisa') hai, jise 1971 mein T.O. Diener ne potato spindle tuber disease ke kaaran ke roop mein discover kiya. Iska RNA low molecular weight ka hota hai, aur poora agent kisi bhi virus se chhota hai.

Prions

Bovine spongiform encephalopathy (BSE), jise mad cow disease ke naam se zyada jaana jaata hai, aur insaanon mein iska counterpart Creutzfeldt–Jakob disease (CJD) nervous system ki infectious diseases hain jinka kaaran ajeeb hai: ek agent jo sirf abnormally folded protein se bana hai, bina nucleic acid ke, lagbhag virus ke size ka.44NCERT doosre naam ki spelling Jacob likhti hai; yeh disease German neurologists Hans Gerhard Creutzfeldt aur Alfons Maria Jakob ke naam par hai. Aise agents ko prions kehte hain.

Lichens

Purani deewaron aur ped ke tano par grey-green parten aur pattedaar dhabbe single organisms jaise dikhte hain, lekin har lichen asal mein do hai: ek fungus aur ek alga jo ek symbiotic partnership mein rehte hain jisse dono ko fayda hota hai (Fig. 2.19). Fungal partner, mycobiont, heterotrophic hai; yeh alga ko shelter deta hai aur dono ke liye paani aur mineral nutrients absorb karta hai. Algal partner, phycobiont, autotrophic hai; yeh photosynthesis karta hai aur banaya hua khaana share karta hai.

Lichens air pollution, khaas kar sulphur dioxide, ke liye bahut sensitive hote hain, aur polluted areas mein nahi ugte. Isliye yeh behtareen pollution indicators hain: lichens se bhare tane saaf hawa ka sanket hain.