Poh-imkv{Xw

-¢mkv XII

kwÿm\ hnZym-̀ ymk Kth-jW ]cn-io-e\ kanXn, (Fkv.-kn.-C.-B¿.-Sn.), tIcfw

2018

tZiob hnZym-̀ ymk Kth-jW ]cn-io-e\ kanXn

First EditionDecember 2006 Pausa 1928

ReprintedJune 2015

PD 255T RPS

© National Council of EducationalResearch and Training, 2007

` 155.00

Printed on 80 GSM paper

Published by the SCERT,ThiruvananthapuramDepartment of Education,Government of Kerala

&

Printed at:Centre for Advanced Printing andTraining (C-apt)(Government of Kerala),Thiruvananthapuram.

ALL RIGHTS RESERVED No part of this publication may be reproduced, stored in a retrieval system or

transmitted, in any form or by any means, electronic, mechanical, photocopying,recording or otherwise without the prior permission of the publisher.

This book is sold subject to the condition that it shall not, by way of trade, be lent,re-sold, hired out or otherwise disposed of without the publisher’s consent, in anyform of binding or cover other than that in which it is published.

The correct price of this publication is the price printed on this page, Any revisedprice indicated by a rubber stamp or by a sticker or by any other means is incorrectand should be unacceptable.

BapJwae-bmf ̀ mj am[y-a-am-°n-s°m≠v GXp hnj-bhpw F{X Bg-Øn¬ ]Tn-°m\pw GXp -

K-l-\-amb Bi-bhpw {]Im-i\w sNøm\pw Ign-tb-≠-Xp-≠v. t{ijvT-̀ m-j-bmbn AwKo-

I-cn-°-s∏´ \ΩpsS ̀ mj-bn¬ lb¿sk-°‚dn ]T-\-Øn\v Ah-kcw \¬Im-\p≈ ]cn-

{i-a-Øns‚ ̀ mK-am-bmWv ]mT-]p-kvX-I-߃ ]cn-̀ m-j-s∏-SpØn {]kn-≤o-I-cn-°p-∂-Xv.

F≥.-kn.-C.-B¿.-Sn. Xbm-dm-°nb F√m tIm¿ hnj-b-ß-fp-sSbpw ]pkvX-I-߃ Fkv.-kn.-

C.-B¿.-Sn. ae-bm-f-Øn-te°v kzX{¥ ]cn-̀ mj \SØn ]pd-Øn-d-°p-I-bm-Wv. hnI-knX

cmPy-߃ amXr-̀ mjbmWv hnZym-̀ ym-k-Øn\p≈ am[y-a-ambn D]-tbm-Kn®p hcp-∂-Xv. tZio-

b-X-e-Øn-ep≈ an° a’-c-∏-co-£-Ifpw {]mtZ-inI ̀ mj-I-fn¬ DØ-c-sa-gp-Xp-∂Xv AwKo-

I-cn-®n-cn-°p∂ Cu Ah-k-c-Øn¬ lb¿sk-°‚dn Xe-Ønepw ae-bm-f-Øn-ep≈ ]pkvX-

I-߃ A\n-hm-cy-am-Wv. tIc-f-Ønse Ip´n-Iƒ Ah-cpsS amXr-̀ m-j-bn¬Øs∂ ⁄m\-

\n¿an-Xn-bn¬ G¿s∏-Sp-∂-Xn\v Cu ]pkvX-I-߃ Ah-k-c-sam-cp-°pw.

]pkvX-I-߃ ]cn-̀ m-j-s∏-Sp-Øp-tºmƒ kmt¶-XnI ]Z-߃ ]c-am-h[n ae-bm-f-Øn-em-°m≥

{ian-®n-́ p-≠v. F∂m¬ ssZ\w-Zn\ hyh-lm-c-Øn\v D]-tbm-Kn-°p∂ ]Z-߃ ae-bmf en]n-

bn¬ AtX ]Sn \ne-\n¿Øm\pw {ian-®n-́ p-≠v. Ip´n-I-fpsS Bi-b-{K-lWw IqSp-X¬

Ffp-∏-am-°p-∂-tXm-sSm∏w ae-bmf ̀ mj-bpsS hf¿®bv°pw Cu ]cn-̀ mj ]pkvX-Iw klm-

b-I-am-Ip-sa∂v \ap°v {]Xym-in-°mw.

tUm.sP. {]kmZv

Ub-d-IvS¿,

Fkv.-kn.-C.-B¿.-Sn. tIcfw

FOREWORDThe National Curriculum Framework (NCF) 2005, recommends that children’s life at school

must be linked to their life outside the school. This principle marks a departure from the

legacy of bookish learning which continues to shape our system and causes a gap between

the school, home and community. The syllabi and textbooks developed on the basis of NCF

signify an attempt to implement this basic idea. They also attempt to discourage rote learning

and the maintenance of sharp boundaries between different subject areas. We hope these

measures will take us significantly further in the direction of a child-centred system of

education outlined in the National Policy on Education (1986).

The success of this effort depends on the steps that school principals and teachers will

take to encourage children to reflect on their own learning and to pursue imaginative activities

and questions. We must recognise that, given space, time and freedom, children generate

new knowledge by engaging with the information passed on to them by adults. Treating the

prescribed textbook as the sole basis of examination is one of the key reasons why other

resources and sites of learning are ignored. Inculcating creativity and initiative is possible if

we perceive and treat children as participants in learning, not as receivers of a fixed body of

knowledge.

These aims imply considerable change in school routines and mode of functioning.

Flexibility in the daily time-table is as necessary as rigour in implementing the annual

calendar so that the required number of teaching days are actually devoted to teaching. The

methods used for teaching and evaluation will also determine how effective this textbook

proves for making children’s life at school a happy experience, rather than a source of stress

or boredom. Syllabus designers have tried to address the problem of curricular burden by

restructuring and reorienting knowledge at different stages with greater consideration for

child psychology and the time available for teaching. The textbook attempts to enhance this

endeavour by giving higher priority and space to opportunities for contemplation and

wondering, discussion in small groups, and activities requiring hands-on experience.

The National Council of Educational Research and Training (NCERT) appreciates the

hard work done by the textbook development committee responsible for this book. We

wish to thank the Chairperson of the advisory group in science and mathematics,

Professor J.V. Narlikar and the Chief Advisor for this book, Professor K. Muralidhar,

Department of Zoology, University of Delhi, Delhi for guiding the work of this committee.

Several teachers contributed to the development of this textbook. We are grateful to their

principals for making this possible. We are indebted to the institutions and organisations which

have generously permitted us to draw upon their resources, material and personnel. We are especially

grateful to the members of the National Monitoring Committee, appointed by the Department of

Secondary and Higher Education, Ministry of Human Resource Development under the Chairmanship

of Professor Mrinal Miri and Professor G.P. Deshpande, for their valuable time and contribution.

As an organisation committed to systemic reform and continuous improvement in the quality

of its products, NCERT welcomes comments and suggestions which will enable us to undertake

further revision and refinement.

Director

New Delhi National Council of Educational

20 November 2006 Research and Training

TEXTBOOK DEVELOPMENT COMMITTEE

CHAIRPERSON, ADVISORY GROUP FOR TEXTBOOKS IN SCIENCE AND MATHEMATICS

J.V. Narlikar, Emeritus Professor, Inter University Centre for Astronomy and Astrophysics(IUCAA), Pune University, Pune

CHIEF ADVISOR

K. Muralidhar, Professor, Department of Zoology, University of Delhi, Delhi

MEMBERS

Ajit Kumar Kavathekar, Reader (Botany), Sri Venkateswara College, University of Delhi, Delhi

B.B.P. Gupta, Professor, Department of Zoology, North-Eastern Hill University, Shillong

B.N. Pandey, Principal, Ordinance Factory Higher Secondary School, Dehradun

C.V. Shimray, Lecturer, Department of Education in Science and Mathematics, NCERT, New Delhi

Dinesh Kumar, Reader, Department of Education in Science and Mathematics, NCERT, New Delhi

J.P. Gaur, Professor, Department of Botany, Banaras Hindu University, Varanasi

J.S. Virdi, Reader, Department of Microbiology, University of Delhi, South Campus, New Delhi

K. Sarath Chandran, Reader (Zoology), Sri Venkateswara College, University of Delhi, Delhi

L.C. Rai, Professor, Department of Botany, Banaras Hindu University, Varanasi

M.M. Chaturvedi, Professor, Department of Zoology, University of Delhi, Delhi

N.V.S.R.K. Prasad, Reader (Botany), Sri Venkateswara College, University of Delhi, Delhi

Sangeeta Sharma, PGT (Biology), Kendriya Vidyalaya, JNU, New Delhi

Savithri Singh, Principal, Acharya Narendra Dev College, University of Delhi, Delhi

Shanti Chandrashekaran, Principal Scientist, Division of Genetics, I.A.R.I., New Delhi

Shardendu, Reader, Department of Botany, Science College, Patna University, Patna

Simminder K. Thukral, Assistant Professor, NIIT Institute of Information Technology, New Delhi

Sunaina Sharma, Lecturer (Biology), Rajkiya Pratibha Vikas Vidyalaya, Dwarka, New Delhi

T.R. Rao, Professor (Retd.) School of Enviornmental Studies, University of Delhi, Delhi

V.K. Kakaria, Reader, Regional Institute of Education, Bhopal

V.V. Anand, Reader, Regional Institute of Education, Mysore

MEMBER-COORDINATOR

B.K. Tripathi, Reader, Department of Education in Science and Mathematics, NCERT, New Delhi

VII

A°m-Z-anIv tImUnt\‰¿

\njn -sI.F.dnk¿®v Hm^o-k¿, Fkv.-kn.C.-B¿.Sn. tIcfw

]cn-̀ mj in¬∏-im-e-bn¬ ]s¶-Sp-Ø-h¿

-KoXm-dmWn B¿.-Fkv.

Pn.F-®v.-F-kv.-F-kv. ]qh-Øq¿, Xncp-h-\-¥-]pcw

tUm. N{μ-Ip-am¿ sI.

Pn.]n.-F-®v.-F-kv.-F-kv. Ipf-\-S, ]Ø-\w-Xn´

^mane C.B¿.

Kh. hn.F®v.-F-kv.-F-kv. Ic-Ipfw

_nt\m-bv hn.Fw.

\h-Po-h≥ F®v.-F-kv.-F-kv. s]¿Sm-e,

Imk¿tKmUv

kp\n¬ Ipam¿ B¿.

Pn.F-®v.-F-kv.-F-kv. Icp-\m-K-]≈n, sIm√w

Acp¨ cho-{μ≥

Pn.F-®v.-F-kv.-F-kv. ]m°w, Imk¿tKmUv

DÆn-Ir-jvW≥ Fkv.

Pn.F-®v.-F-kv.-F-kv. shÃv I√-S, sIm√w

KoXm-\m-b¿ Fkv.

Pn.hn.F-®v.-F-kv.-F-kv. t^m¿ tKƒkv,

\S-°m-hv, tImgn-t°mSv

_nPp-°p-´≥ F.sI.

Pn.F®v.-F-kv.-F-kv. Aø≥tIm-bn-°¬, sIm√w

{ioIp-am-cn -sI.Pn.

_n.F-®v.-F-kv.-F-kv. Icp-\m-K-]-≈n, sIm√w

kPn-dmWn B¿.

apl-Ω-Z≥ Kh. F®v.-F-kv.-F-kv. CS-Ø-d,

]Ø-\m-]pcw, sIm√w

-hn-Z-Kv[¿

-tUm. A\n¬ Ipam¿ hn.-Fkv.

Akn-Â v s{]m^-k¿ (t_m´-Wn)

Kh. tImtf-Pv, Imk¿tKmUv

tUm. tPmkvIp-´n C.sP.

Akn-Â v s{]m^-k¿ (t_m´-Wn)

Kh. {_Æ≥ tImtf-Pv, Xe-ti-cn, IÆq¿

tUm. at\m -tam-l≥ B‚Wn

Akn-Â v s{]m^-k¿ (kpthm-fPn)

bqWn-th-gvkn‰n tImtf-Pv, Xncp-h-\-¥-]pcw

tUm. {ioc-RvPnXv Ipam¿ kn.hn.

Akn-Â v s{]m^-k¿ (kpthm-fPn)

Kh. hnIvtSm-dnb tImtf-Pv, ]me-°mSv

tUm. sI.F-kv.km-P≥

Akn-Â v s{]m^-k¿ (kpthm-f-Pn)

F≥.-F-kv.-F-kv.-s{S-bv\nwKv tImtf-Pv,

H‰-∏m-ew, ]me-°mSv

{]q v̂ do-UnMv

aS-hq¿ iin

VIII

D≈-S°w

bqWn‰v VI {]Xyp-¬∏m-Z\w 11 - 88

A[-ymbw 1 : {]Xyp-¸m-Z\w Pohn-I-fn 13

A[-ymbw 2 : ssewKnI {]Xyp¸m-Z\w k]p-jv]n-I-fn 31

A[-ymbw 3 : {]Xyp-¸m-Z\w a\p-jy-\n 56

A[-ymbw 4 : {]P-\-\m-tcmKyw 76

bqWn‰v VII P\n-X-I-im-kv{Xhpw ]cnWmahpw 89 - 182

A[-ymbw 5 : ]mc-º-cy-Øn-s‚bpw 91

hyXn-bm-\-Øn-s‚bpw XXz-߃

A[-ymbw 6 : ]mcºcyØns‚ X≥am-{XmSnÿm\w 123

A[-ymbw 7 : ]cn-Wmaw 159

bqWn‰v VIII Poh-imkv{Xw a\p-jy-\-∑-bv°mbn 183 - 240

A[-ymbw 8 : a\p-jys‚ Btcm-Kyhpw tcmK-ßfpw 185

A[-ymbw 9 : `t£ym¬∏mZ\w h¿[n∏n°m\p≈ D]mb߃ 211

A[-ymbw10 : kq£va-Po-hn-Iƒ a\p-jy-t£-a-Øn\v 228

IX

bqWn‰v IX ssPh-km-t¶-Xn-I-hnZy 241 - 272

A[-ymbw11: ssPh-km-t¶-XnIhnZy: 243

XXz-ßfpw {]{In-b-Ifpw

A[-ymbw12: ssPhkmt¶XnIhnZybpw 261

AXns‚ {]tbmP\ßfpw

bqWn‰v X ]cn-ÿnXnimkv{Xw 273 - 352

A[-ymbw 13 : PohnIfpw PohnKWhpw 275

A[-ymbw 14 : Bhm-k-hy-hÿ 299

A[-ymbw 15 : ssPh-ssh-hn-[yhpw kwc-£-Whpw 319

A[-ymbw 16 : ]mcn-ÿn-XnI {]iv\-߃ 332

X