Biology

Standard XI

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The Coordination Committee formed by GR No. Abhyas - 2116/(Pra.Kra.43/16) SD - 4
Dated 25.4.2016 has given approval to prescribe this textbook in its meeting held on
20.06.2019 and it has been decided to implement it from academic year 2019-20.

BIOLOGY

Standard XI

2019
Maharashtra State Bureau of Textbook Production and

Curriculum Research, Pune.

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First Edition : 2019 © Maharashtra State Bureau of Textbook Production and Curriculum Research, Pune - 411 004.
Reprint : 2020
The Maharashtra State Bureau of Textbook Production and Curriculum
Research reserves all rights relating to the book. No part of this book
should be reproduced without the written permission of the Director,
Maharashtra State Bureau of Textbook Production and Curriculum
Research, ‘Balbharati’, Senapati Bapat Marg, Pune 411004.

Subject Committee: Illustrations and cover :
Dr. Chandrashekhar V. Murumkar, Shri Vivekanand S. Patil
(Chairman)
Dr. Avinash Ade Coordinator :
Dr. Naikare Shriram Maruti Shri. Rajiv Arun Patole
Dr. Prakash Lohar Special Officer (Biology)
Dr. Madhav Pralhad Bhilve Typesetting : DTP Section, Textbook
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Dr. Kiran Randive Bureau, Pune
Shri. Rajiv Arun Patole Paper : 70 GSM Cream wove
(Member Secretary) Print Order :
Printer :
Study Group:
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The Constitution of India

Preamble

WE, THE PEOPLE OF INDIA, having

solemnly resolved to constitute India into a

SOVEREIGN SOCIALIST SECULAR

DEMOCRATIC REPUBLIC and to secure to

all its citizens:

JUSTICE, social, economic and political;

LIBERTY of thought, expression, belief, faith

and worship;

EQUALITY of status and    of opportunity;

and to promote among them all

FRATERNITY assuring the dignity of

the individual and the unity and integrity of the

Nation;

IN OUR CONSTITUENT ASSEMBLY this

twenty-sixth day of November, 1949, do HEREBY

ADOPT, ENACT AND GIVE TO OURSELVES

THIS CONSTITUTION.

NATIONAL ANTHEM

Preface

Dear Students,

We welcome you all to Std. XI. For the first time, you are being introduced to the subject of
Biology as a separate discipline. You have already been acquainted with some of the concepts of
Biological Sciences from Standard five onwards, especially in the subject of General Science up to
standard Eight and Science and Technology for standard Nine and Ten.

This textbook aims to create awareness about the biological sciences specially Botany,
Zoology and allied aspects of biological sciences. The National Curriculum Framework (NCF)
was formulated in 2005, followed by the State Curriculum Framework (SCF) in 2010. Based on
the given these two frameworks, reconstruction of the curriculum and preparation of a revised
syllabus has been undertaken which will be introduced from the academic year 2019-20. The
textbook incorporating the revised syllabus has been prepared and designed by the Maharashtra
State Bureau of Textbook Production and Curriculum Research, (Balbharati), Pune.

The subject biology intends to give students understanding, and appreciation of the vast diversity
of living beings, their special adaptations to their environments and evolutionary relationships. No
compromise is made in any manner over the use of language in the Biology context, but at the same
time, the textbook is presented in a simple language. In addition, relevant diagrams, graphs, tables
used in the textbook will bring about more clarity in the understanding of various terminologies and
biological concepts. All the illustrations are in colour form. This will enable students to understand
various concepts of botany and zoology thoroughly and correlate this with their day-to-day
practical life. The new syllabus focuses on the conceptual principles of overall life processes, its
understanding, and application in day-to-day life and ability to solve different upcoming problems
and issues like conservation; different diseases and remedies, the application of technology, etc.
The general teaching-learning objectives of the revised syllabus are further determined based on the
‘principle of constructivism’ i.e. self-learning.

The curriculum and syllabus confirms to the maxims of teaching such as moving from
concrete to abstract, known to unknown and from part to whole. For the first time, in the syllabus
of biology various independent activities have been introduced. These activities will not only help
to understand the content knowledge but also provide scope for gaining relevant and additional
application based knowledge on your own efforts. The detailed information of all concepts is also
provided for the better understanding of the subject. Q. R. Code have been introduced for gaining
the additional information, abstracts of chapters and practice questions/ activities.

The efforts taken to prepare the textbook will not only enrich the meaningful learning experience
of the students, but also benefit other stakeholders such as teachers, parents as well as those aspiring
candidates preparing for the competitive examinations.

We look forward to a positive response from the teachers and students.
Our best wishes to all!

(Dr. Sunil Magar)

Place : Pune Director
Date : 20 June 2019
Bharatiya Saur : 30 Jyestha 1941 Maharashtra State Bureau of Textbook
Production and Curriculum Research,

Pune, 411004

- For Teachers -

Dear Teachers, • Exercises provided after each unit are
  We are happy to introduce the revised prepared using different parameters like

textbook of Biology for Std XI. This book is a observation, co-relation, critical thinking,

sincere attempt to follow the maxims of teaching analytical reasoning etc.
• Evaluation pattern should be based on
as well as develop a ‘constructive’ approach to
the above mentioned parameters. Equal
enhance the quality of learning. The demand
weight age should be assigned to all the
for more activity based, experiential and
topics. Use different combinations of
innovative learning opportunities is the need
questions. Stereotype questions should be
of the hour. The present curriculum has been
avoided.
restructured so as to bridge the credibility gap • Use demonstration, discussion method for

that exists between what is taught and what teaching.
• ‘Can You Recall’ is the first main starting
students learn from direct experience in the
point of lesson which helps for the
outside world. Guidelines provided below will
introduction of topic. This will also helpful
help to enrich the teaching-learning process
for students regarding understanding the
and achieve the desired learning outcomes.
• To begin with, get familiar with the content of lesson.
• Use QR Code given in the textbook.
textbook yourself.
• The present book has been prepared for Keep checking the QR Code for updated

constructive and activity-based teaching. information.
• Teachers must skillfully plan and organize • ‘Internet My Friend’ is used for collecting

the activities provided in each chapter to extra important information related to topic.
• ‘Use Your Brain Power’ is used for the
develop interest as well as to stimulate the
application level questions in different
thought process among the students.
• Always teach with proper planning. lessons.
• Use teaching aids as required for the proper • ‘Do Your Self’, ‘Find Out’, ‘Observe

understanding of the subject. and Discuss’ and ‘Try This’ are used for
• Do not finish the chapter in short.
• Follow the order of the chapters strictly as activity based learning.
• ‘Know the Scientist’ is used for the
listed in the contents because the units are
information of different scientist related to
introduced in a graded manner to facilitate
concepts in lesson.
knowledge building. • ‘Activity’ is used in lesson and exercise for
• Facilitate peer learning as much as
better understanding and application of the
possible by reorganizing the class structure
content which studied.
frequently. • Exercise is given at the end of lesson.
• Teaching-learning interactions, processes
In exercise different type of questions/
and participations of all students are very
activities are given.
essential and so is your active guidance. • Teacher should use their freedom to
• Ask questions based on previous
acquaint the students with flora and fauna
knowledge of different concepts of lesson.
• Do not use the boxes titled ‘Do you of given region.
• Remember that mathematical and
know?’ for evaluation. However, teachers
statistical tools are also important to
must ensure that students read this extra
understand biology
information. • List of abbreviations are provided
• Information provided in boxes with the
towards the end of the textbook for further
title ‘Can You Tell’, ‘Always Remember’
clarification.
should be considered for evaluation.
Best wishes for a wonderful teaching

experience and fruitful welcome!

Competency Statements

Standard XI

Unit Competency Statements
Diversity in After studying the content in Textbook students will …
living world
• Analyse basic characteristics of living and non-living.
Cell structure • Collect and analyse useful data by observing diversity of living organisms using
and functions
different tools.
Structural • Describe plants and animals in the surrounding on scientific basic and classify
organization
in organisms them using taxonomic hierarchy.
• Develop hobbies by watching and collecting the things (livings) and their
Plant
physiology conservation using databases.
• Classify different organisms based on cell structure, body organisation, mode of

nutrition etc.
• Compare and analyse similarities and differences along with phylogeny amongst

different groups of organisms.
• Recognize, analyse and compare structural similarities and differences and

progressive evolutionary changes in different plants and animals.

• Explain and draw the structure and functions of different cell organelles.
• Elaborate the role of nucleus in heredity and controlling characters with structure

of chromosome.
• Compare cell division process and know their role in life cycle of organisms.
• Analyse and specify different biomolecules of cell with their role in structural and

functional aspect of cell.
• Explain basic morphology of dominant plant group of this era i.e. Angiosperms.
• Compare morphological features of different plant parts in different plant families.
• Draw floral parts and floral diagram.
• Identify economic importance of Angiosperms with respect to fruit and seeds.
• Compare morphological feature of two major classes of Angiosperms.
• Explain different types of tissues in plants and reasons for growth viz. primary

and secondary.
• Analyse basic differences in anatomy of different plants like dicot and monocots

with respect to root, stem and leaf.
• Elaborate different animal tissues and their role.
• Explain and draw mechanisms of different physiological process like digestion

and excretion.
• Review the contribution of different scientists in systematics and taxonomy.

• Explain the scientific reasons behind the various physiological activities based
on relationship.

• Understand the relationship between chemical reactions of molecules in daily
life and analyse them to solve various problems.

• Review the contribution made by different workers.

• Plan and implement programs about conservation of environment.

• Explain the importance of green energy and save energy in daily life.

Animal • Explain the need and importance of various physiological processes.
Physiology • Explain the structural modifications, observed in various living organisms to carry

out various physiological processes.
• Observe and correlate the histological structure of various organs with their

function.
• Comprehend mechanisms by which these physiological processes help maintain

homeostasis.
• Create memory maps, flow charts to depict major events in these processes.
• Develop insight about connection between life style/habits and physiological

disorders.
• Collect information about latest diagnostic tools and treatments for various

physiological disorders.
• Critically analyse given situational data and come up with rationale of possible

physiological disorders/suggest proper remedial measures.
• Perform various analytical tests to detect presence of certain components in food

materials/waste products.

Contents

Sr. No. Name of the lesson Page No.

1. Living World 1-5
2. Systematics of Living Organisms 6 - 18
3. Kingdom Plantae 19 - 28
4. Kingdom Animalia 29 - 43
5. Cell Structure and Organization 44 - 58
6. Biomolecules 59 - 75
7. Cell Division 76 - 84
8. Plant Tissues and Anatomy 85 - 96
9. Morphology of Flowering Plants 97 - 115
10. Animal Tissue 116 - 126
11. Study of Animal Type : Cockroach 127 - 137
12. Photosynthesis 138 - 150
13. Respiration and Energy Transfer 151 - 160
14. Human Nutrition 161 - 173
15. Excretion and Osmoregulation 174 - 192
16. Skeleton and Movement 193 - 214

DISCLAIMER Note : All attempts have been made to contact copy right/s (©) but we have not heard from them. We
will be pleased to acknowledge the copy right holder (s) in our next edition if we learn from them.

1. Living World

C an y ou recall? There is immense diversity in living
1. What is the difference between livings organisms. Since time immemorial, variety of
organisms are living together on earth. In order
and non-livings? to understand the interrelations between living
2. Enlist the characters of living organisms. and non-living as well as between two living
3. Whether all organism are similar? Justify beings or groups, systematic study of these is
essential. This data is also important for various
your answer. industries and agriculture. Intensive laboratory
and field studies in order to identify and classify
Planet earth is made up of abiotic and the organisms form strong basis for meaningful
biotic components. The biotic components are use of the collected data. If we need to study this
obviously the living beings present around us. diversity, certain aids called taxonomical aids
The question is why do we call them living and can be used. These includes herbaria, botanical
how do they differ from non-living? gardens, museums, biodiversity parks, etc.

1.1 Basic principles of life : 1. Can you tell?
A. The living being once produced / born has 1. How can we study large number of
to survive. For survival, it needs energy and
many chemical molecules. For energy, it has to organisms at a glance?
perform metabolism. Metabolism is breaking 2. Whether all organisms prepare their own
of molecules (catabolism) and making of new
molecules (anabolism). food?
B. From birth onwards, organisms show 3. Which feature can be considered as all
tendency of growth and development. This
growth is a well-orchestrated process. You inclusive characteristic of life? Why?
might have observed sand mounds, boulders
grow, etc.This growth is not from within and Think about it
hence these are not living beings.
C. Growth and development are not the 1. Can metabolic reactions demonstrated in
processes which have unlimited time span. At a test tube (called ‘in vitro’ tests) be called
certain point of time, the molecules, organs, living?
systems begin to lose their effective working
and become old. This is ageing process of the 2. Now a days patients are declared ‘brain
body. dead’ and are on life support. They do not
D. Life has to continue hence the organism show any sign of self-consciousness. Are
tries to produce a young one like itself. It is they living or non - living?
possible through reproduction (asexual or
sexual). This ensures continuity of race. Mules, 1.2 Herbarium :
sterile worker bees do not reproduce; yet are The word herbarium (plural-herbaria)
living. Can we call reproduction as inclusive was coined by Pitton de Tournefort in the
characteristic of life? book ‘Elemens’. The art of herbarium was
E. As the body loses it's capacity to perform initiated by an Italian taxonomist Luca Ghini
metabolism, the organism dies. (1490-1556). Herbaria are effective tools in
taxonomic studies. A herbarium is essentially
F. Any living being responds to thermal, a dried plant specimen that is pressed, treated
chemical or biological changes in the and mounted on standard size sheet in order to
surrounding. Responsiveness or irritability is preserve it.
unique property of living beings.

1

Date, place of collection along with Know the scientists
detailed classification and highlighting with its
ecological peculiarities, characters of the plant In 1543, first
are recorded on the same sheet. Local names botanical garden of the
and name of the collector may be added. This world was established
information is given at lower right corner of by an Italian Prof.
sheet and is called 'label'. Luca Ghini (A. D.
1490-1556) at Pisa,
Italy. Botanical garden
at Kew in England
is known for largest
collection of more Prof. Luca Ghini
than 30,000 specimens (preserved plants) and
more than 7 million herbaria.

Fig. 1.1 Herbarium Internet my friend

1.3 Botanical Gardens : Collect information about Prof.
Botanical gardens are the places where Almeida, Prof. V. N. Naik, Dr. A. V. Sathe,
plants of different varieties collected from Dr. P. G. Patwardhan with reference to
different parts of the world, are grown in a their taxonomic work and biodiversity
scientific and systematic in a in vivo manner. conservation.
Plants are labeled. The label-board shows
scientific as well as common name of the plant.

Fig. 1.2 Botanical Garden : Kolkata 255 years old Banyan tree

2

Conservation of Biodiversity : 1.5 Zoological Parks :
Biodiversity is the degree of variation Zoological Park generally known as
of life forms in an ecosystem. Biodiversity zoo, is a place of interest for common man.
is essential to maintain ecological stability. In a zoo, wild animals are kept in captivity.
The extent of complexity and density of They are protected and care is taken to provide
biodiversity can be regarded as a measure conditions similar to their natural habitat. (ex-
of health of an ecosystem. Population situ) In a zoo, a naturalist can study food habits
explosion and over exploitation of resources and behavior of animals.
have resulted in loss of biodiversity at Flora, manuals, Monographs and
an alarming rate. Conservation involves Catalogue are some other tools of maintaining
attempting to slow down, stop or even reverse biodiversity records. Flora is the plant
the loss in the natural habitat of organism. life occurring in a particular area on time.
This is known as in-situ conservation. Why A Monograph describes any one selected
does the loss of biodiversity matter? For biological group where as manual provides
many people, it is a simple moral or ethical information, keys about identification of species
issue. We share our planet with a huge range found in a particular area.
of other organisms and we have no right to
harm them. Biodiversity helps to maintain
stability in an ecosystem. Loss of one variety
of organisms can affect entire ecosystem.

1.4 Museum : Fig. 1.4 Zoological Park
Museums are the places where,
collections of preserved plant and animal 1. C an you tell? 1. What are the
specimens are kept. Plant and animal
specimens may be preserved in formalin (10% essentials of a good herbarium?
to 40% formaledehyde) in transperent jars.
Jars are labelled. Larger animals like birds and 2. Why should we visit botanical gardens,
mammals are usually stuffed and preserved. museums and zoo?
This science is known as taxidermy. Specimens
in dried form are also kept in museum. 3. What is 'ex-situ' and 'in-situ' conservation?
We can even find systematic collections
of shells, skeletons of animals, insect boxes in
museums.
Thus, biological museums in
educational institutes are reference hubs of
biodiversity studies.

Fig. 1.3 Biological Museum 1.6 Biodiversity parks :
It is an ecological assemblage of
species that form self-sustaining communities
on degraded / barren landscape e.g. Late
Uttamrao Patil biodiversity park Gureghar,
Mahabaleshwar. This park is the best model
for conservation of natural heritage in urban
landscape.

3

Systematic classification of living 1.7 Key :
organisms is helpful in understanding Key is taxonomical aid used for
the interrelations. In order to understand classification of plants and animals. The keys
interrelations between organisms and maintain are based on contrasting characters. One of the
harmony on planet earth, study of biodiversity contrasting characters gets accepted and other
is a must. rejected. The statement in key is called a lead.
Normally keys are analytical in nature. Let us
Know the scientists study about classification of living organisms
in next chapter.
Dr. S. P. Agharkar
D o you k now ?
One of the leading When plants from any forest locality
botanists of India, Dr. are conserved on the name of holy place it is
S. P. Agharkar was born called as sacred grove these also considered
in November 1884 in as sacred natural sites by IUCN.
Malvan, Maharashtra. He
explored biodiversity of Internet my friend
Western Ghats where he
came across a species of freshwater jellyfish, 1. Collect information about botanical gar-
which was until then only known to be found dens, zoological parks and biodiversity hot
in Africa. These findings were published spots in India.
in scientific journal Nature in 1912. Dr.
Annandale, the Superintendent of the Indian 2. Collect information of endemic flora and
Museum in Kolkata, helped Dr.Agharkar in fauna of India.
his further endeavours to collect, preserve and
conduct microscopic examinations of animal
and plant specimens. The institute ARI, Pune
has been named after his name.

Find out

Human being is at key position in maintaining biodiversity of earth. Find out more
information about the following.
1. Laws to protect and conserve biodiversity in India.
2. Environmental effects of ambitious projects like connecting rivers or connecting cities by

constructing roads.
3. Did Bauxite mining in Western Ghats affect critically endangered species like – Black

panther, different Ceropegia spp., Eriocanlon spp.?

4

Exercise

1. Choose correct option E. What do you understand from terms like
in situ and ex situ conservation?
A. Which is not a property of living being?
4. Write short notes
a. Metabolism A. Role of human being in biodiversity
b. Decay conservation.
c. Growth B. Importance of botanical garden.
d. Reproduction
5. How can you, as an individual, prevent the
B. Aparticular plant is strictly seasonal plant. loss of Biodiversity?
Which one of the following is best suited
if it is to be studied in the laboratory? Practical / Project :

a. Herbarium 1. Make herbarium under the guidance of
b. Museum your teacher.
c. Botanical garden
d. Flower exhibition 2. Find out information about any one
sacred grove (devrai) in Maharashtra.
C. A group of students found two
cockroaches in the classroom. They had
a debate whether they are alive or dead.
Which life property will help them to do
so?

a. Metabolism
b. Growth
c. Irritability
d. Reproduction

2. Distinguish between botanical gardens,
zoological park and biodiversity park
with reference to characteristics

3. Answer the following questions

A. Jijamata Udyan, the famous zoo in
Mumbai has acclimatised humbolt
penguins. Why should penguins be
acclimatised when kept at a place away
from their natural habitat?

B. Riya found peculiar plant on her visit to
Himachal Pradesh. What are the ways
she can show it to her biology teacher and
get information about it?

C. At Andaman, authorities do not allow
tourists to collect shells from beaches.
Why it must be so?

D. Why do we have green house in botanical
gardens?

5

2. Systematics of Living Organisms

Can you recall? Natural : It is the classification which is based
on objectively significant rather than being
What is five kingdom system of selected for convenience like artificial system
of classification e.g. Bentham and Hooker's
classification? system of classification.

There is a great diversity of organisms Phylogenetic : It is the classification based on
around us. Since time immemorial, we common evolutionary descent. e.g. Engler and
humans have been exploiting this wealth for Prantl classification.
our own benefit. During this process man In the system of classification the terms
tried to differentiate between and identify like ‘taxa’ and ‘categories’ are often used. Each
the organisms. This evolved into a branch of category is referred as a unit of classification.
biology known as classification that has led In fact, it represents a rank and is commonly
eventually to systematics. The methods of termed as taxon.
classification dates back to ancient time when
Indian, Greek and Roman philosophers have Archaea
contributed their might to systematise science.
Bacteria Eukarya
2.1 Systematics :
‘‘Systematics is the study of kinds and Common ancestor
diversity of organisms and their comparative
and evolutionary relationship’’(G. Simpson, Fig 2.1 Phylogenetic descent
1961).
2.3 Three domains of life :
Taxonomy : It is believed that the life originated on
Taxonomy means classification earth in its very simple form. Constant struggle
following certain rules or principles. Word of the early living beings gave rise to more and
Taxonomy comes from two Greek words, more perfect forms of life. This struggle and
taxis – meaning arrangement and nomous progress is evolution which led to formation of
meaning law or rule. The term taxonomy was diverse life forms. Carl Woese in 1990 proposed
first introduced by A. P. de Candolle (Swiss three domains of life to classify life forms. They
Botanist) [1778-1841]. are Archaea, Bacteria and Eukarya. Domain is
an unit larger than Kingdom in the system of
2.2 Classification : classification.
It is the arrangement of organisms Bacteria and Archaea both have
or groups of organisms in distinct categories prokaryotic cells where as Eukarya have
in accordance with a particular and well eukaryotic cell. All the three domains have
established plan. This classification is based very unique ribosomal RNA (rRNA). Archaea
on similarities and dissimilarities among the are known for their survival in very extreme
organisms. conditions like high temperature, salinity,
acidic conditions, etc. Bacteria, though are
Artificial : prokaryotes differ from Archaea in structure of
It is the classification that is based on cell wall.
few easily observable and non-evolutionary
features such as habit, colour, etc.; often
irrespective of their affinity (relationship)
with other organisms. e.g. Linnaeus system of
classification.

6

2.4 Chemotaxonomy : It helps to study newly identified
It is method of biological classification species as well as understanding ecological
based on similarities and differences in and evolutionary relationships between living
structure of certain compounds present among beings. The process of DNA barcoding includes
the organisms being classified. In short, it is the two basic steps: (a) collecting DNA barcode
classification based on chemical constituents data of known species and (b) matching the
of organisms. e.g. Archaea cell wall is without barcode sequence of the unknown sample
peptidoglycan and that of Prokarya is with against the barcode library for identification.
peptidoglycan. Among Eukarya, fungi have DNA barcoding has many applications. A
chitinous cell wall while plants have cellulosic few to mention are, protection of endangered
cell wall. species, preservation of natural resources,
pest control in agriculture, identifying disease
2.5 Numerical taxonomy : vectors, authentication of natural health
The system is based on quantification products and identification of medicinal plants.
of characters and develops an algorithm for
classification. The basic aim of this taxonomy Can you tell?
was to create a taxonomy using numeric
algorithms like cluster analysis rather than 1. Which characters of organisms are visible
using subjective evaluation of their properties. characters?
This system was first proposed by Sokel and
Sneath in 1963. 2. Name the recent approaches in taxonomy.
3. What is DNA barcoding?
2.6 Cladogram : 4. What is evolution?
It is a typical branching pattern. As 5. Enlist uses of taxonomy.
shown on previous page, a diagram of three
domains of life is a cladogram. It represents 2.9 Taxonomic Categories :
a hypothetical relationship denoting a Classification is not a single step
comparison of organisms and their common process but involves hierarchy of steps in which
ancestors. each step represents a rank or category. Since
the category is a part of overall taxonomic
2.7 Phylogeny : arrangement it is called taxonomic category
It is evolutionary relationship of and all categories together constitute the
organism. It is an important tool in classification taxonomic hierarchy. Kingdom, division, class,
as it takes into account not merely the order, family, genus, species are the categories
morphological status but also the relationship in hirarchial sequence. These are compulsory
of one group of organism with other groups categories. Besides, there are some facultative
of life. The system helps to understand the categories like sub-order, sub-family, etc. to be
evolution and also focuses on the similarities used as per need.
of their metabolic functioning. Woese’s three
domain concept as well as Whittakar’s five 2.10 Taxonomic Hierarchy :
kingdom system are very good examples of
phylogenetic relationship. Taxon : A taxon is a taxonomic group
of any rank in the system of classification
2.8 DNA barcoding : (H.J. Lam 1948) e.g. in plant kingdom each
DNA barcoding, is a new method for one of the following such as Angiospermae,
the identification of any species based on its Dicotyledonae, Polypetalae, Malvaceae
DNA sequence from a tiny tissue sample of the represents a taxonomic group i.e. a taxon.
organism under study.

7

Category Taxon Taxon • Cohort / Order : It is taxonomic rank
used in the classification of organisms and
Kingdom Plantae Animalia recognised by nomenclature codes. An order
Division/Phylum Angiospermae Chordata is a group of closely related families showing
Class Dicotyledonae Reptilia definite affinities. Order thus is a step above
family in taxonomic hierarchy. Members
Sub-class Polypetalae Diapsida belonging to same order but different families
Series Thalamiflorae - may show very few dissimilarities. e.g. family
Order Malvales - Papavaraceae, Brassicaceae, Capparidaceae,
Squamata etc with parietal plancentation are grouped
in order Parietales. Families of dogs and cats
Family Malvaceae Elapidae though are different, they belong to same order
Carnivora.
Genus Hibiscus Naja • Class : The class is the distinct
taxonomic rank of biological classification
Species rosa-sinensis naja having its own distinctive name. A group of
higher taxonomic rank than order. Class is the
Table 2.2 Classification of China-rose and assemblage of closely allied orders. Orders
Carnivora and order Primates belong to class
Cobra Mammalia. Thus monkeys, gorillas, gibbons
(Primates) and dogs, cats, tigers (Carnivora)
2.11 Units of Classification : belong to same class.
• Species : Species is the principle • Division / Phylom : The division is
natural taxonomic unit, ranking below a genus a category composed of related classes e.g.
and denoted by latin binomial (considered as division. Angiospermae includes two classes
the basic) unit of classification. It is a group - Dicotyledonae and Monocotyledonae (In
of organisms that can interbreed under natural animal classification division is a sub-unit of
condition to produce fertile offspring. It was Category / Phylum).
thought to be an indivisible, stable and static • Sub-kingdom : Different divisions
unit. However in the modern taxonomy, sub- having some similarities form sub-kingdom.
division of species such as sub-species, varities e.g. The divisions Angiospermae and
and populations are seen and given more Gymnospermae will the sub-kingdom
importance. Phanerogams or Spermatophyta.

• Genus : Genus is a taxonomic rank • Kingdom : It is the highest taxonomic
or category larger than species used in the category composed of different sub-
biological classification of living and fossil kingdoms. e.g. sub-kingdom Phanerogams
organisms. Genus is a group of species bearing and Cryptogams form the Plant kingdom or
close resemblance to one another in their Plantae which includes all the plants while all
morphological characters but they do not animals are included in kindom Animalia.
interbreed. e.g. Tiger, Leopard, Lion all three
belong to same genus Panthera. They have The taxonomic categories we have
common characters yet are different from considered so far are broad categories.
each other because their genus is same but Scientists have added sub-categories to these
species are different. Another example is genus in order to place organisms in more scientific
Solanum. Brinjal and potato both belong to this manner. You will observe that as we go higher
genus. in taxonomical ladder, number of common
characters go on decreasing.
• Family : It is one of the major
hierarchial taxonomic rank. A family represents
a group of closely related genera. e.g. genera
like Hibiscus, Gossypium, Sida, Bombax are
included in same family Malvaceae. Cat also
belongs to family of leopards, tigers and lions,
family Felidae but dog belongs to different
family Canidae.

8

If we are comparing two organisms Before 2011, the code which was set up
that are related to each other only at division or to confirm the scientific names was ICBN
phylum level, their classification may become means International Code of Botanical
difficult. Nomenclature. Recently XIX International
Botanical Congress (IBC) was held in
Can you tell? Shenzhen, China in July 2017. This code
is also called "Shenzhen code", so the old
1. Why horse and ass are considered to be code ICBN has been changed to ICNAFP
two different species or animals? means "International Code of Nomenclature
for Algae, Fungi and Plants". This code was
2. Make a flow chart showing taxonomic published on 26th June 2018.
hierarchy.
According to this system the scientific
2.12 Nomenclature : name of sunflower is Helianthus annuus. In
Any object that becomes known to the above Helianthus indicates name of the
human intelligence must possess a name. It genus (generic name) and second word annuus
may not be possible or convenient to describe it denotes name of the species.
in order to communicate ideas about it. The art
of naming the objects is in fact, a science called The Binomial Nomenclature system follows
nomenclature. All living organisms are known certain rules.
by a particular name. y Name of organism is composed of two

1. Vernacular / Local names / Common Latin / Greek words.
names: Widely distributed organisms have y Generic epithet is a simple noun. It should
a large number of common names. Pansy
(Viola tricolor L.) grown in most European come first and begin with capital letter.
and American gardens has about 50 common y Specific epithet is the descriptive adjective
English names. In a multilingual country like
India, almost all useful plants have local names which should come later and begin with
which differ from language to language and small letter.
even from dialect to dialect. As in Ayurveda, y Scientific epithet must be underlined
mango (Mangifera indica L.) is known by over separately if hand written and must be
50 different names, all in the Sanskrit language. printed in italics.
y The generic and specific epithet should not
Hence the common names obviously have have less than three letters and more than
limited usage and for universal applications, a thirteen letters.
unique name for a particular individual is very y Usually the name of the author who names
much essential. a plant or animal is also written in full or
abbreviated form after scientific name. e.g.
2. Scientific Names : To overcome the Mangifera indica L. Where L stands for
difficulties raised by common names, scientists Linnaeus.
have given scientific names to all the known
organisms. These are systematic, thus provide Internet my friend
means for international communication.
Initially the polynomial system was used 1. Collect the information about most
but Carl Linnaeus used binomial system of
nomenclature. He introduced this system in his recent system of classification of living
book ‘‘Species Plantarum’’ published in 1753. organisms and Kingdom System of
International Code of Botanical Nomenclature Classification. e.g. Search for APG
(ICBN) has been set up to confirm the scientific system of classification for Plants.
names. 2. Collect the information about
classification systems for all types of
organisms.

9

Know the scientists Membrane bound organelles e.g.
mitochondria, chloroplast, endoplasmic
Carl Linnaeus classified living reticulum are absent. Ribosomes are smaller in
organisms in two kingdoms based on mode size (70S) than in eukaryotic cells. The mode of
of nutrition, whether they are migratory, reproduction in monera is asexual or with the
sedentary, etc. But this broad classification help of binary fission or budding. Very rarely,
as Kingdom Plantae and Kingdom Animalia sexual reproduction is by conjugation method.
was found inadequate. It could not classify Morphologicaly, bacteria are
the organisms that show characters of both the categorised into four groups, the spherical-
Kingdoms for ex. Bacteria, Fungi, Euglena Coccus, the rod-shaped bacillus, the comma or
etc. Hence to avoid confusion scientist R.H. kidney shaped- vibrio and the spiral- spirillum.
Whittaker (1969) proposed Five Kingdom On the basis of evolution, bacteria can
system of classification. This system shows be classified as Archaebacteria and Eubacteria.
the Phylogenetic relationship between the
organisms. The five kingdoms are. Coccus Coccobacillus Vibrio Bacillus

1. Kingdom Monera Spirillum Spirochete
2. Kingdom Protista
3. Kingdom Plantae Fig. 2.3 Different shapes of bacterial cells
4. Kingdom Fungi
5. Kingdom Animalia a. Archebacteria :
These are differentiated from other
R. H. Whittaker bacteria on the basis of their different cellular
features. These bacteria are mostly found
2.13 Salient features of Five Kingdoms : in the extreme environments; hence termed
extremophiles. They are found in a variety
1. Kingdom Monera : of places from volcanic craters to salty lakes
and hot springs. Their ability to withstand such
It contains unicellular organisms with hostile environment speaks of their capacity
prokaryotic cellular organization. Monera to survive in very severe conditions. Bacteria
includes unicellular prokaryotic organisms. that can withstand high salinities are called
These are omnipresent. They are found in all halophiles while those that withstand extreme
types of environment which are not generally temperature are known as thermophiles. A
inhabited by other living beings. Few are very common example is of methanogenic
photoautotrophs or chemoautotrophs; but bacteria found in gut of ruminants (cows and
majority are heterotrophic in nature. These buffaloes). These bacteria help in production of
organisms do not have well defined nucleus. methane in biogas plants.
DNA exists as a simple double stranded b. Eubacteria :
circular single chromosome called as nucleoid. These are commonly referred as true
Smaller circular molecules of DNA as extra- bacteria. They have cell wall of peptidoglycan.
chromosomal genetic elements called plasmids They are found as autotrophs and heterotrophs.
are often present. Cell wall is made up of The autotrophs can be photosynthetic like
peptidoglycan (also called murein) which is a Chlorobium (Green sulphur bacteria) and
polymer of sugars and amino acids. Chromatium or chemosynthetic like sulphur
bacteria.

10

These are mostly multicellular 2. Kingdom Protista :
filamentous forms living in fresh water. The This group includes all the unicellular
body is covered by mucilagenous sheath. but eukaryotic organisms. These organisms
The genetic material is typical prokaryotic. show link with all eukaryotic Kingdoms like
Chl-a, Chl-b, carotenes and xanthothylls are Plantae, Fungi and Animalia.
the photosynthetic pigments. Filaments show
heterocyst which helps in nitrogen fixation. a. Plant-like protists :
Heterotrophs are the most abundant. They are also termed Chrysophytes.
Most of them are decomposers and known They are commonly termed phyto-planktons.
for breaking down large molecules in simple They are microscopic and mostly photosynthetic
molecules or minerals. They can be anaerobes and are major producers in oceans. Most of
helping in curdling of milk (Lactobacilli), them are referred to as diatoms as the have
fixation of nitrogen (Azotobacter), antibiotic body wall made up of two soap-box like fitting
production (Streptomyces), composting and silica covers. “Diatomaceous earth" is nothing
degrading oil. But the story doesn’t end here, but these shells left behind for so many years.
some of them are pathogens i.e. causing disease Diatomaceous earth is granular hence finds use
(typhoid, cholera, tuberculosis, tetanus). in polishing and filtration.

Heterocyst

Mucilagenous
sheath

Fig. 2.4 Cynaobacterium (Nostoc) Fig. 2.5 Diatoms

Can you tell? b. Animal-like Protists :- They are also termed
1. What are salient features of Monera? protozoans. They lack cell wall. They are
2. What will be the shape of a bacillus and heterotrophs. They are believed to be primitive
animal forms. Amoeboid protozoans have
coccus type of bacteria? pseudopodia as locomotory organs. Amoeba is
3. Write a note on useful and harmful free living form but Entamoeba is endoparasite
and causes amoebic dysentery. Flagellated
bacteria. protozoans have flagella as locomotory
organ. Trypanosoma is a common flagellated
Mycoplasma : pathogen which causes sleeping sickness.
These are smallest of the living forms.
They do not have cell wall. Many forms are Paramoecium is a cilliate protozoan
pathogenic. They are found resistant to having cilia for locomotion. In Paramoecium,
common antibiotics due to absence of cell wall. gullet (a cavity) opens on the cell surface.
Plasmodium is a sporozoan protozoa. It causes
malaria. It forms spores in one of its life stage.

11

Contractile Euglenoids :- They lack cell wall but have a
Micronucleus Macronucleus vacuole tough covering of proteinaceous pellicle.
They possess two flagella, one short
Food and other long. They behave as heterotrophs in
Vacuoles absence of light but possess pigments, similar
to that of higher plants, for photosynthesis.
Cilia

Cytopyge

Gullet Nucleus Nucleolus
Lysosomes Trichocyst Oral Groove Mitochondria
Chloroplasts
Fig. 2.6 Paramoecium Flagellum
Stored
Dinoflagellates :- These are aquatic (mostly carbohydrate
marine) and photosynthetic. The cell wall
is made up of cellulosic stiff plates. They Photoreceptor Endoplasmic
possess a pair of flagella. They have a wide reticulum
range photosynthetic pigments, which can be
yellow, green, brown, blue and red. Gonyaulax Golgi apparatus
is dinoflagellate that is responsible for famous Contractile vacuole
‘red tide’. It makes even sea appear red.
Fig. 2.8 Euglena

Apical horn 3. Kingdom Plantae:
Flagellar pore (s) The kingdom is dominated by
autotrophs. It also includes some semi-
Epitheca autotrophic members, the insectivorous plants
like Venus fly trap, pitcher plant, bladderwort,
Cingulum as well as heterotrophic parasitic members
like Cuscuta. Members of this kingdom
Hypotheca Flagella Plates are multicellular, having eukaryotic cells
containing chlorophyll. Cells have cell wall
Sulcus mostly made up of cellulose. Plants exhibit
Ventral view alternation of generation i.e., life cycle has two
distinct phases. Kingdom Plantae is divided into
Anatomical horns two major groups Cryptogamae / Cryptogams
Dorsal view and Phanerogamae / Phanerogams.

We will study this kingdom in detail in
next chapter.

Fig. 2.7 Gonyaulax 4. Kingdom Fungi : These are eukaryotic
heterotrophs showing extracellular digestion.
c. Fungi like protists :- They are commonly They are found in warm and humid places. They
from the group Myxomycetes. These are have simple body which may be unicellular or
saprophytic organisms found on decaying made up of long thread like structures called
leaves. Their cells aggregate to form a large hyphae. Large fungi such as mushrooms have
cell mass called plasmodium (not a malaria a compact mass of cells. Unicellular organisms
parasite). The spores produced by plasmodium have a protoplast with many nuclei. e.g.
are very tough and survive even very harsh Rhizopus, Saccharomyces (Yeast-unicellular
conditions. fungus).

12

Filamentous fungi consist of a body b. Ascomycetes :
called mycellium in which hyphae are present. These are called as sac-fungi. These
The hyphae may be with septa or without fungi are mostly multicellular. Rarely
septa. They may be uni or multinucleate. The unicellular varieties include yeast. The hyphae
non-septate multinucleate hyphae are called are branched and septate. Sac fungi can be
coenocytic hyphae. The cell wall in fungi is decomposers, parasites or coprophilous (grow
composed of chitin, a polysaccharide or fungal on dung). Morels and truffles are varieties
cellulose. The fungi exhibit hetrotrophic mode of sac fungi that are consumed as delicacies.
of nutrition. Mostly they are saprophytic, some Neurospora is useful in genetic and biochemical
are parasitic or predators. They reproduce assays.
sexually as well as asexually. Asexual Ex. Aspergillus, Penicillium, Claviceps,
reproduction takes place by fragmentation, Neurospora, Saccharomyces.
fission and budding. Some fungi are symbiotic;
either live with algae as lichens or as mycorrhiza Fig. 2.10 Aspergillus
in association with roots of higher plants.
They are useful as well as harmful. c. Basidiomycetes :
Mushrooms are consumed as food, yeast is These are commonly called club fungi.
used in bakery and breweries. Penicillium, a They have branched, septate hyphae. e.g.
fungus, is well known for antibiotic production. Agaricus (mushrooms), Ganoderma (bracket
Harmful fungi cause diseases in plants and fungi), Ustilago (smuts), Puccinia (rusts), etc.
animals, e.g. Puccinia.
The fungi are further classified on the
basis of their structure, mode of spore formation
and fruiting bodies as follows-

a. Phycomycetes :
These are commonly called algal fungi.
Mycelium is made up of aseptate coenocytic
hyphae. They commonly grow in moist and
damp habitats, on decaying organic matter as
well as in aquatic habitats or as parasites on
plants.
e.g. Mucor, Rhizopus (bread mould),
Albugo (parasitic fungus on mustard).

Sporangium
Sporangiophore

Hypha

Fig. 2.9 Mucor Fig. 2.11 Mushroom

d. Deuteromycetes :
These are called imperfect fungi, which
are known to reproduce only asexually.
e.g. Alternaria, Colletotrichum.

13

Fig. 2.12 Alternaria 5. Kingdom Animalia : Members of this
kingdom are heterotrophs; adapted to holozoic
Do you know ? nutrition. Most of them have capacity of
locomotion. They are multicellular eukaryotes
Lichens : Lichen is co-existence of algae and where cells lack chlorophyll as well as cell
fungi for mutual benefit. Algal member, the wall. Growth is determinate (follow definite
phycobiont as it is called, mostly belongs to pattern).
cyanobacteria (blue-green algae) or green In chapter four, we will study
algae. Fungal member is called mycobiont. about Kingdom- Animalia and its further
They are excellent example of symbiosis. The classification.
algal component of lichens provides food to
fungal part while fungus provides shelter to Can you tell?
alga and also absorbed water and minerals
to alga. The association is intense and it is 1. Differentiate between Plantae and
difficult to identify them as separate living Animalia.
beings.
Thoughfoundinextremeenvironments 2. How are fungi different from plants?
like snow clad poles, lichens are sensitive 3. Have you seen any diseased plant in your
to pollution. They are not found in polluted
regions, hence are considered as pollution farm?
indicators. Lichens also play important
role in soil formation by using specific acid Do you know ?
productions.
New variety of Banana seedlings
Lichen - produced by tissue culture technique like
e.g. Parmelia ‘Shrimanti’, Basarai, G-9 are virus free
varieties.
Can you tell?
1. Write a note on economic importance of Viruses, Viroids are groups of acellular
organisms that are not included in Whitaker’s
fungi. Five Kingdom classification.
2. Why are fungi considered as heterotrophic
2.14 Acellular organisms :
organisms? a. Viruses : Viruses were named so by Louis
3. What are coenocytic hyphae? Pasteur; considering the meaning, Venom or
4. Classify fungi into their types. poison. These obligate parasites were given
the name 'virus' by M. J. Beijernek, after
observation that they were able to migrate in
an agar gel. Thus, being and infectious soluble
agent, he called the filtrate as 'contagium
vivum fluidum'. It was scientist Stanley who
demonstrated that viruses are inert outside
the host cell and can be crystallised. They are
made up of proteins.
Viruses lack their own cell machinery.
They have protein coat (capsid) around nucleic
acid strand, thus considered to be acellular
organisms. Viruses are inactive outside a host
cell; but once they enter their specific host cell,
they take charge of cellular machinery of host

14

cell and duplicate themselves. Viruses thus can Collar Head
be called infectious nucleoprotein particles.
Core
Types of viruses : Sheath
As per genetic material, viruses are
grouped as DNA or RNA viruses.

Do you know ? Basal plate
Tail fibers
Viruses have either DNA or RNA as
their genetic material but never DNA as well
as RNA.

Fig. 2.14 Bacteriophage

Hollow core b. Viroids : Potato spindle tuber disease was
Radius 40 Ao found to be caused by single stranded RNA
which lacks protein coat. T. O. Diener in 1971
RNA reported that this is low molecular weight
Capsomeres RNA and smaller in size than viruses. These
infectious RNA strands are called viroids.
RNA

Pitch 23 Ao Can you tell?

Fig. 2.13 Tobacco mosaic virus (TMV) 1. Why are viruses called infectious
nucleoproteins?
Protein coat called capsid is made up of
smaller units, the capsomeres. Capsomeres are 2. Describe genetic material in plant
arranged in polyhedral or helical forms. Capsid and animal viruses as well as in
protects genetic material. bacteriophages.
The genetic material in viruses is either
single-stranded RNA or single or double- 3. Differentiate between viruses and viroids.
stranded RNA or double-stranded DNA.
Viruses that infect bacterial cells are called In ternet my fri end
bacteriophages which normally have double- Prions : In modern medicine, certain
stranded DNA. infectious neurological diseases were found
Viruses cause disorders like leaf curling, to be transmitted by abnormally folded
yellowing, mosaic formation etc. in plants. You proteins. These proteins are called prions.
have heard of foot and mouth disease in animals The word prion comes from ‘proteinaceous
or swine flu which are viral diseases. Small infectious particle’. e.g. mad cow disease in
pox, mumps, herpes to common cold, viruses cattle, Jacob's disease in human. Find more
are the causative agents of many diseases in information about prions.
humans. The list includes AIDS too!

15

Observe and Discuss Complete the following table on the basis of previous

knowledge.

Characters Monera Protista Fungi Plantae Animalia
Cell type Prokaryotic
Eukaryotic Eukaryotic Eukaryotic Eukaryotic

Cell wall -------- Present in some ............... Present ...............
Absent organisms Present (cellulose)
Nuclear Present ................ Present
membrane Unicellular
Body ................. Multicellular/ Tissue /organ Tissue/
organization loose tissue organ
Autotrophic /system
Mode of ............. Photosynthetic Autotrophic
nutrition Heterotrophic ................... (Photosynthetic) --------
....................
Ecological Decomposers Decomposers ................. Consumers
role

Do Yourself

Complete the following table through collecting information about sunflower,
tiger with characteristic features.

Category Taxon Characteristics
Kingdom

Sunflower

Category Taxon Characteristics
Kingdom

Tiger

16

Exercise

1. Choose correct option 5. Draw neat labelled diagrams
A. Paramoecium
A. Which of the following shows single B. Euglena
C. TMV
stranded RNA and lacks protein coat?
6. Complete chart and explain in your word
a. Bacteriophage b. Plant virus

c. Viroid d. Animal virus

B. Causative agent of red tide is
_____________.
a. Dinoflagellate b. Euglenoid Types of Viruses Animals
c. Chrysophyte d. Lichen

C. Select odd one out for Heterotrophic 7. Identify the following diagrams, label
bacteria. them and write detail information in
your words
a. Nitrogen fixing bacteria
b. Lactobacilli
c. Methanogens
d. Cyanobacteria
D. Paramoecium : Ciliated Protist

Plasmodium : ____________

a. Amoeboid protozoan b. Ciliophora
c. Flagellate protozoan d. Sporozoan

2. Answer the following A
A. What are the salient features of monera?
B. What will be the shape of bacillus and
coccus type of bacteria?
C. Why is binomial nomenclature
important?

3. Write short notes
A. Useful and harmful bacteria.
B. Five Kingdom system
C. Useful Fungi

4. Complete tree diagram in detail

Fungi

B

Protista

17

8. The scientific name of sunflower is given
below. Identify the correctly written
name.
A. Helianthus annuus L.

B. Helianthus Annuus l.

9. Match the following.

Kingdom Example

C i. Monera a. Riccia
D ii. Protista b. Cyanobacteria
iii. Plantae c. Rhizopus
E iv. Fungi d. Diatoms
F
10. Complete the following

A. Plant-like Protista -

B. - Entamoeba

Practical / Project :

1. Make a group of students. Observe
living organisms in your school/college
campus and try to write their characters
with respect to habit, habitat, mode
of nutrition, growth- determinate or
indeterminate, type of reproduction
- vegetative reproduction - asexual
reproduction - Sexual reproduction.

With the help of similarity and
dissimilarity, try to classify organisms
into different categories. Similar work
should implement for animal group.

2. Find out types of lichens and its economic
importance.

18

3. Kingdom Plantae

Can you recall? Ob serve and Di scuss
Collect different water samples of
1. Why do we call as plants producers on fresh water. Mount them on a glass slide and
observe under a compound microscope. Try
land ? to identify the organisms which are visible
2. What are differences between under it.

sub-kingdoms Cryptogamae and 3.2 Salient features of major plant
Phanerogamae? groups under Cryptogams :
3. Differentiate between Thallophytes and
Bryophytes. A. Division : Thallophyta - Members
4. Give any two examples of Pteridophyta. are mostly aquatic, few grow on other plants
as epiphytes. Some grow symbiotically and
3.1 Kingdom plantae : epizoic i.e. growing or living non-parasitically
In earlier chapter, we have studied on the exterior of living organisms. Aquatic
different aspects of classification. algae grow in marine or fresh water. Most of
Kingdom Plantae is further classified them are free living while some are symbiotic.
on the basis of characteristics like absence
or presence of seeds, vascular tissues, Plant body is thalloid i.e. undifferentiated
differentiation of plant body, etc. into root, stem and leaves. They may be small,
• Phanerogams are commonly called seed unicellular, microscopic like Chlorella (non-
motile), Chlamydomonas (motile). They can
producing plants. They produce special be multicellular, unbranched, filamentous like
reproductive structures that are visible Spirogyra or branched, filamentous like Chara.
(Phaneros – visible) Sargassum, a huge macroscopic sea weed
• Cryptogams are spore producing plants which measures more than 60 meters in length
and do not produce seeds and flowers. is also an alga.
They reproduce sexually by gametes but
sex organs are concealed (kryptos : hidden,
gamos : marriage).

Classification of Kingdom Plantae is
represented as follows :

Kingdom- Plantae

Cryptogams Phanerogams

Non-Vascular Plants Vascular Plants Vascular Plants

Thallophyta Bryophyta Pteridophyta Gymnosperms Angiosperms

Dicotyledonae Monocotyledonae
Chart 3.1 Classification of Kingdom Plantae

19

The algal cell wall contains either Pyrenoids are located on Chloroplast.
polysacchrides like cellulose / glucose or a Members are rich in protein, so used as food;
verity of proteins or both. Reserve food is in the used even by space travellers. e.g. Chlorella.
form of starch and its other forms. Reprocuction
takes place by vegetative asexual and sexual Chlamydomonas, Spirogyra, Chara, Volvox,
way. The life cycle shows phenomenon of
alternation of generation, dominant haploid and Ulothrix etc.
reduced diploid phases. Algae are classified as
per its pigments like chlorophyll, xanthophylls Internet my friend
and phycobilin.
1. Make a list of green algae with their
a. Chlorophyceae (green algae) : characteristic shape of chloroplast.
These are mostly fresh water (few
brackish water and marine). 2. Enlist the forms of filamentous algae.
Plant body is unicellular, colonial, filamentous. 3. Write different pigments found algae.
Cell wall contains cellulose.
Chloroplasts are of various shapes b. Phaeophyceae (Brown algae) :
like discoid, plate-like, reticulate, cup-shaped, Plant body : Mostly marine, rarely
ribbon-shaped or spiral with chlorophyll a and fresh water. Simple branched / filamentous (e.g.
b. The stored food is in the form of starch. Ectocarpus) / profusely branched (Petalonia).
Cell wall has cellulose, fucans
Chloroplast and algin. Photosynthetic pigments like
chlorophyll-a, -c and fucoxanthin are present.
Nucleus Mannitol, laminarin and starch are stored
food materials. Body is usually differentiated
Chlamydomonas into holdfast, stalk called stipe and leaf-like
photosynthetic organ called frond. Many
Pyrenoid (starch storage) species of marine algae are used as food.
Mitochondria (Amino acid synthesis) e.g. Laminaria, Sargassum. Some species
are used for production of hydrocolloids. e.g.
Ectocarpus, Fucus, etc.

Chara Oogonium Lamina
(contains eggs) Stipe
Holdfast
Antheridium
(contains sperm)

Gametophyte

Mucilage Cell membrane Laminaria Sargassum

Cell wall Cytoplasm

Spirogyra

Cytoplasm Nucleus Pyrenoid Fucus
strand Chloroplast Vacuole Fig. 3.3 Phaeophyceae

Fig. 3.2 Chlorophyceae

20

c. Rhodophyceae (Red algae) : Can you tell?
Plant body These are found in marine
as well as fresh water on the surface, deep sea 1. What are the three major groups of
and brakish water. Plant body is thalloid. Cells Cryptogams ?
contain chlorophyll a, d and phycoerythrin.
Cell wall is made up of cellulose and pectin 2. Name the accessory pigments of algae.
glued with other carbohydrates. Stored food is 3. Give salient features of algae.
in the form of Floridean starch. Commercially
important agar-agar which is used as solidifying Differentiate between Chlorophyceae and
agent in tissue culture medium is obtained from Phaeophyceae.
red algae. e.g. Chondrus, Batrachospermum 4. Enlist examples of Chlorophyceae and
Porphyra, Gelidium , Gracillaria, Polysiphonia, Rhodophyceae.
etc.
Observe and Discuss
Batrachospermum
You may have seen Funaria plant in
Gracillaria rainy season. Why is it called amphibious
plant?
Polysiphonia
B. Bryophyta
Fig. 3.4 Rhodophyceae (Bryon : moss ; phyton : plant)
Internet my friend
1. Economic importance of algae. Bryophytes are mostly terrestrial
2. Role of algae in environment. plants. They are found in moist shady places.
3. Different forms of green, red, brown and But they need water for fertilization and
blue green algae. completion of their life cycle. Hence they
are called ‘amphibious plants’. They include
Do you know ? approximately 960 genera and about 25,000
Brown algae- kelps may grow up species.
to 100 meters in height. Find out more Life cycle of Bryophytes shows
information about Sargasso sea. sporophytic and gametophytic stages.
Vegetative plant body is thalloid or leafy which
represents gametophytic generation. Spore
producing capsule represents sporophytic
generation.
Bryophytes have root-like structures
called rhizoids. Rhizoids are unicellular in
liverworts while multicellular in mosses.
Rhizoids absorb water and minerals and also
help in fixation of thallus on the substratum.

Bryophytes are divided into two groups :
liverworts and mosses.

a. Liverworts (Hepaticeae) :
These are lower members of Bryophyta.
These are primitive group of Bryophytes.
Gametophyte possesses flat plant body called
thallus. The thallus is green, dorsiventral,
prostrate with unicellular rhizoids. e.g. Riccia,

Marchantia.

21

Hornworts (Anthocerotae) - These member Economic importance -
possess flattened thallus. The thallus produces
horny structures which are called sporophytes Some mosses provide food for
hence the name hornworts. e.g. Anthoceros. herbivorous mammals, birds, etc. Species of
Sphagnum, a moss; provides peat used as fuel.
b. Mosses (Musci) : Mosses are also used as packing material for
These are advanced members of transport of living materials because they
Bryophyta which possess erect plant body. have significant water holding capacity. Just
Gametophytic phase of the life cycle like lichens, mosses are the first living beings
includes two stages namely; protonema stage to grow on rocks. They decompose rocks to
and leafy stage. The protonema is prostrate form soil and make them suitable for growth
green, branched and filamentous (it is also of higher plants. Dense layers of mosses help
called juvenile gametophyte). It bears many in prevention of soil erosion, thus act as soil
buds. Leafy stage is produced from each binders.
bud. Thus protonema helps in the vegetative
propagation. The leafy stage has erect, slender C. Pteridophyta
stem like (Cauloid) main axis bearing spiral (Pteron : feather, phyton : plant)
leaf like structures (Phylloid). It is fixed in soil
by multicellular branched rhizoids. This stage Evolutionarily, Pteridophytes are the
bears sex organs. Vegetative reproduction first vascular and true land plants. Hence
takes place by fragmentation and budding in considered as the first successful terrestrial
secondary protonema. plants with true roots, stem and leaves. These
e.g. Funaria, Polytrichum, Sphagnum, etc. plants have a primitive conducting system and
they are the only Cryptogams with vascular
tissues. The late Paleozoic era is regarded as the
age of Pteridophytes. The group has about 400
genera and 11,000 species. The plants consist
of pinnate (feather like) leaves. Leaves may
be small called microphylls (e.g. Selaginella)
or large called macrophylls (e.g. Nephrolepis /
fern).

Blade

Riccia (Liverworts) Anthoceros

Capsule Sporophyte Rhizome Frond
Gametophyte
Seta Back side Roots Front side
foot

Main axis Rhizoids

Funaria 22

Fig. 3.5 Mosses Fig. 3.6 Nephrolepis (Fern)

Observe and Discuss Observe and Discuss
Observe all garden plants like Cycas,
You may have seen the various plants Thuja, Pinus, Sunflower, Canna and compare
which do not bear flowers, fruits and seeds them. Note similarities and dissimilarities
but they have well developed root, stem and among them. Which differences did you notice
leaves. Discuss. between Gymnosperms and Angiosperms?
3.3 Salient features of major plant groups
Pteridophytes grow in moist and shady under Phanerogams
places. Pteridophytes show sporophytic and A. Gymnospermae
gametophytic stages in life cycle. e.g. Ferns,
Horsetail. Some are aquatic (Azolla, Marsilea), (Gymnos : naked, sperma : seed) :-
xerophytic (Equisetum) and epiphytic There are about 70 genera and 1000
(Lycopodium). living species of Gymnosperms in world. In
Pteriodphytes show heteromorphic India it is represented by 16 genera and 53
alternation of generations in which the species.
sporophyte is diploid, dominant, autotrophic
and independent. It is differentiated into root, Foliage leaves
stem and leaves. The primary root is short lived
and soon replaced by adventitious roots while b. Corraloid roots
the stem may be aerial or underground. Leaves of Cycas
may be scaly (Equisetum) simple and sessile
(Lycopodium) or large and pinnately compound Stem
(Nephrolepis / Ferns).
In these members Xylem consists of a. Cycas plant body
only tracheids and Phloem consists of only
sieve cells. Secondary growth is not seen in Algal zone
Pteridophytes due to absence of cambium.
c. T. S. of Coralloid
Pteridophytes are classified as - root of Cycas
Psilopsida- (Psilotum), Lycopsida - (Selaginella
and Lycopodium), Sphenopsida - (Equiesetum)
and Pteropsida - (Dryopteris, Pteris and
Adiantum)

Economic importance - Pteridophytes are
Used for medicinal purpose and as soil binders.
Many varieties are grown as ornamental plants.

Can you tell? d. Male cone of Cycas
having
1. Distinguish between Bryophyta and
Pteridophyta. microsporophylls

2. Why Bryophyta are called amphibians of e. Megasporophyll of Cycas
Plant Kingdom?
Fig. 3.7 Cycas plant details
3. Pteridophytes are also known as vascular
Cryptogams - Justify.

4. Give one example of aquatic and
xerophytic Pteridophytes.

23

Most of the Gymnosperms are Do you know ?
evergreen, shrubs or woody trees. These are
primitive group of flowering plants producing Gymnosperms like Ginkgo biloba is
naked seeds. They are vascular plants having called living fossil. It is because the plant is
Xylem with tracheids and Phloem with sieve found in living as well as fossil form and the
cells. number of fossil forms is much more than the
living forms.
The plant body is sporophyte. It is Gymnosperms vary in their size. e.g.
differentiated into root, stem and leaves. The Sequoia sempervirens is the tallest living plant
root system is tap root type. In some, roots form in the world. It is commonly called coast red
symbiotic association with other life forms. wood of California. The height of the plant is
Coralloid roots of Cycas show association about 366 feet. Taxodium mucronatum has a
with blue green algae and roots of Pinus girth of about 125 feet. Zamia pygmaea is the
show association with endophytic fungi called smallest Gymnosperms and is about 25 cm
mycorrhizae. only.
In Gymnosperms, stem is mostly erect,
aerial, solid and cylindrical. Secondary growth Try this
is seen in Gymnosperms due to presence of Study the leaves of Hibiscus, Peepal,
cambium. In Cycas it is usually unbranched, Canna, Grass and Tulsi. Classify them as
while in conifers it is branched. The leaves Monocot and Dicot.
are diamorphic. The foliage leaves are green,
simple needle like or pinnately compound, Can you recall?
where as scale leaves are small, membranous
and brown. Spores are produced by 1. What are the salient features of
microsporophyll (Male) and megasporophyll Angiosperms?
(Female).
2. What is double fertilization ?
Economic importance - Cycas is grown as 3. Explain in brief two classes of
ornamental plant. Pinus is used as source of
pine wood, turpentine oil and pine resin. Angiosperms? Draw and label one
example of each class.

Fig. 3.8 Pinus tree with cones B. Angiospermae (Angios : enclosed :
vessel, Sperma : seed)

Angiosperms are the most advanced
group of flowering plants. In these plants the
seeds are enclosed within the fruit i.e. ovary.
Angiosperms is a group of highly evolved
plants, primarily adapted to terrestrial habitat.
They vary in size.

Angiosperms show heteromorphic
alternation of generation in which the
sporophyte is diploid, dominant, autotrophic
and independent. The gametophytes (male or
female) are haploid, reduced, parasitic and
concealed.

24

Angiosperms are heterosporous. a. Monocotyledonae : These plants have
Microspores (commonly called pollens) are single cotyledon in their embryo. They have
formed in microsporangia (or anthers). They adventitious root system and stem is rarely
develop in highly specialized microsporophyll branched. Leaves generally have sheathing leaf
or stamens while megaspores are formed in base and parallel venation while the flowers
megasporangia (or ovules) borne on highly are generally trimerous.
specialized megasporophyll called carpel.
Besides the essential whorls of The vascular bundles are conjoint,
microsporophylls (Androecium) and collateral and closed type. In Monocots, except
megasporophylls (Gynoecium) there are few plants secondary growth is absent. e.g. Zea
accessory whorls namely calyx (sepals) and mays (Maize), Sorghum vulgare (Jowar).
corolla (petals) arranged together to form
flowers. Corn seed Tassel

D o you k now ? Leaf blade Silks
Wolffia is the smallest Angiosperm,
1mm in size and Eucalyptus grows to over Ear
100 meters. Roots

Angiosperms are subdivided into two classes: Fig. 3.10 Zea mays (Maize)
a. Dicotyledonae : These plants have two
cotyledons in their embryo. They have a tap Can you tell?
root system and the stem is branched. Leaves
show reticulate venation while the flowers 1. Give general characters of Gymnosperms
show tetra or pentamerous symmetry. and Angiosperms.
Vascular bundles are conjoint, collateral
and open type. Cambium is present between 2. Distinguish between Dicotyledonae and
Xylem and Phloem for secondary growth. In Monocotyledonae.
Dicots secondary growth is commonly found.
e.g. Helianthus annuus (sunflower), Hibiscus 3. Why do Dicots show secondary growth
rosa-sinensis (China rose). while Monocots don't?

Seeds 3.4 Plant life cycle and alternation of
generations:
Ray florets Life cycle of a plant includes two phases
or distinct generations namely sporophyte
Disc florets (diploid : 2n) and gametophyte (haploid : n).
Some special diploid cells of sporophyte divide
Stem by meiosis to produce haploid cells. These
Tap root haploid cells divide mitotically to give rise
to gametophyte. The gametophyte produces
Inflorescence male and female gametes which fuse during
of Sunflower fertilization to produce diploid zygote. It
divides by mitosis to form diploid sporophyte.
Fig. 3.9 Helianthus annuus (Sunflower) The sporophytic and gametophytic generations
generally occur alternately in the life cycle of
a plant. This phenomenon is called alternation
of generations.

25

Distinct alternation of these two Sporophyte (2n)
generations is observed in Bryophytes
and Pteridophytes. In Gymnosperms and Zygote Sporophyte Meiosis
Angiosperms, gametophyte is much reduced (2n) phase
and exists within sporophyte. In algae, based Spores
upon the nature of dominant phase in life Fertilization Gametophyte (1n)
cycle, it is called haplontic, diplontic or haplo- phase
diplontic life cycle. Gametes
In Bryophytes haploid gametophyte (1n)
is dominant. It is photosynthetic, independent
thalloid or erect phase. Sporophyte is short Gametophyte (1n)
lived, multicellular and depends totally
or partially on gametophyte for nutrition Fig. 3.11 Alternation of generation
and anchorage. Whereas in Pteridophytes,
sporophyte is dominant, independent and C an you tell?
vascular plant body. Haploid multicellular 1. What is alternation of generations?
gametophyte is generally autotrophic and short 2. Which phase is dominant in the life cycle
lived. It alternates with Sporophyte.
of Bryophyta and Pteridophyta ?

Diplontic Haplontic Haplo-Diplontic

Haploid single-cell or Haploid multicellular

Gametes multicellular organism organism

n Mitosis Mitosis Mitosis Mitosis

Spores
Spores
Gametes

Fertilization Meiosis Meiosis Fertilization Meiosis
Fertilization

2n Mitosis Diploid Plants and Diploid
multicellular some algae multicellular
Fungi and
organism
In animals organism some algae

Fig. 3.12 Types of life cycle

Diplontic : Haplontic : Haplo-diplontic :
Here mitosis occurs
Here mitotic in haploid cells. It results in the Here mitosis
formation of single haploid cells or
divisions occurs only in a multicellular haploid organism. occur in both diploid
These forms produce the gametes
diploid cells. Gametes through mitosis. Zygote is formed and haploid cells. These
After fertilization. This cell is the
formed through meiosis are only diploid cell in the entire life organisms undergo through
cycle of the organism. Thus the same
haploid in nature. The diploid zygotic cell later undergoes meiosis. a phase in which they are
E.g. Some Algae and Fungi.
zygote divide mitotically. multicellular and haploid

In this process production (the gametophyte), and a

of multicellular diploid phase in which they are

organism or in the production multicellular and diploid

of many diploid single cells (the sporophyte). E.g. Land

takes place. E.g. Animals. plants and in many algae.

26

Exercise

1. Choose correct option 4. Differentiate between Dicotyledonae and
Monocotyledonae based on the following
A. Which is the dominant phase in Pteri- characters
dophytes? a. Type of roots

a. Capsule b. Gametophyte b. Venation in the leaves

c. Sporophyte d. Embryo c. Symmetry of flower

B. The tallest living gymnosperm among 5. Answer the following questions
the following is ..........
a. Sequoia sempervirens A. We observe that land becomes barren
b. Taxodium mucronatum soon after monsoon. But in the next
c. Zamia pygmaea monsoon it flourishes again with
d. Ginkgo biloba varieties we observed in season earlier.
How you think it takes place?
C. In Bryophytes ..........
a. Sporophyte and gametophyte B. Fern is a vascular plant. Yet it is not
generations are independent considered a Phanerogams. Why?
b. Sporophyte is partially dependent
upon gametophyte C. Chlamydomonas is microscopic whereas
c. Gametophyte is dependent upon Sargassum is macroscopic; both are
Sporophyte algae. Which characters of these plants
d. Inconspicuous gametophyte includes them in one group?

D. A characteristic of Angiosperm is ......... 6. Girth of a Maize plant does not increase
a. Collateral vascular bundles over a period of time. Justify
b. Radial vascular bundles
c. Seed formation 7. Radha observed a plant in rainy season
on the compound wall of her school. The
d. Double fertilization plant did not have true roots but rootlike
structures were present. To which group
E. Angiosperms differ from Gymnosperms the plant may belong?
in having ..........
a. Vessels in wood 8. Draw neat labelled diagrams
A. Spirogyra
b. Mode of nutrition B. Chlamydomonas
c. Siphonogamy C. Funaria
D. Nephrolepis
d. Enclosed seed E. Haplontic and haplodiplontic life cycle

2. How you place the pea, jawar and fern
at its proper systematic position? Draw a
flow chart with example of.

3. Complete the following table

Groups of algae Chlorophyceae Phaeophyceae Rhodophyceae
1. Stored food
2. Cell Wall Starch

Cellulose and algin

3. Major pigments Chl- a, d and Phycoerythrin

27

9. Identify the plant groups on the basis of 10. Observe the following diagram. Correct
following features. it and write the information in your
A. Seed producing plants words.
B. Spore producing plants
C. Plant body undifferenciated into Root, Sporophyte (2n)
Stem and leaves
D. Plant need water for fertilization Gametes
E. First vascular plants (1n)

Practical / Project : Meiosis Gametophyte Fertilization
phase
1. Study the Nephrolepis plant in detail. Zygote
2. Study the coralloid roots, scale leaf (2n) Sporophyte
phase
and megasporophyll of cycas in
detail.

Spores
(1n)

28

4. Kingdom Animalia

Can you recall? c. Tube within tube body plan : Digestive
1. What is the basis for classification ? system is present in tube-like body cavity.
2. Who proposed Five Kingdom Mouth and anus are present at two separate
ends of digestive system. Annelida onwards all
classification system? phyla show this type of body plan.
3. What is the need and importance of
Fig. 4.3 Fish
classification?
Observe and Discuss
You are familiar with animals, their
general characteristics and great diversity Observe the diagram given below and
observed in this group. Let us learn about how discuss the criterias of classification.
this diverse group is classified systematically.
Diploblast Triploblast
4.1 Criteria used for animal classification:
Grades of organization - Cellular, Endoderm
Cell-Tissue, Tissue-Organ, Body Symmetry-
Assymmetry, Radial Symmetry, Bilateral Digestive
Symmetry, Body Cavity - Acoelomate, cavity
Pseudocoelomate, Coelomate. Germ Layers
-Diploblastic, Triploblastic. Segmentation- Ectoderm
Unsegmented, Segmented.
Non-living layer Mesoderm
4.2 Animal body plan :
a. Cell aggregate plan : In this body plan, cells
do not form tissues or organs. Their is minimal
differentiation and division of labour among
cells. It is found in porifera.

Fig. 4.1 Sponge Asymmetry Radial Bilateral
b. Blind sac body plan : In this body plan,
body is like a sac with single opening. Digestion Types of Symmetry
is carried out in this sac-like structure where
ingestion and egestion takes place through same 4.3 Animal Classification :
opening. e.g. Members of Phylum Cnidaria.
1. Phylum : Porifera
Mouth (pori-pores; feron-bearing)

Fig. 4.2 Hydra e.g. Scypha, Euspongia (Bath sponge),
Euplectella (Venus' flower basket)
These are aquatic animals, most of
them are marine and few are fresh water. They
are also called 'sponges'.

29

Most of them have asymmetrical body. They reproduce asexually as well as
Body of these animals consists of many cells sexually. Asexual reproduction is performed by
with little division of labour. Hence their body fragmentation and gemmule formation. These
is considered as a colony of different types of animals have ability of regeneration. Sexual
cells. reproduction is performed by formation of
These are sedentary animals. On their gametes. Fertilization is internal. Development
body, they bear numerous minute pores called takes place through indirect larval stage.
'ostia' through which water enters in the body
cavity- spongocoel. Water leaves the body Osculum
through single large opening called 'osculum'.
Water is circulated in the body through Silica spicules
the 'canal system'. During its circulation, cells
of the animal body absorb food, exchange Ostium
respiratory gases and release excretory
products. central Epidermis Collar Mesohyl
cavity (semi fluid
Osculum
matrix)
Ostia
Choanocyte

Flagellum Nucleus

Choanocyte holdfast
Apopyle
Body Fig. 4.5 Typical Sponge body

Internet my friend

Common Which are the larval stages of Porifera?
Base
2. Phylum : Cnidaria
a. Sycon e.g. Hydra, Aurelia (Jelly fish), Physalia
(Portuguese man-of-war), Adamsia (sea
b. Euspongia c. Euplectella anemone), Diploria (Brain coral), Gorgonia
(sea fan).
Fig. 4.4 Animals - Porifera They are aquatic, mostly marine and
few are fresh water forms. They are sessile or
Spongocoel is lined by special free swimming. They show radial symmetry
flagellated cells called 'choanocytes' or 'collar and are diploblastic with blind-sac body
cells'. Beating of flagella creates water current. plan. Animals exhibit two body forms. Polyp
Body of these animals is supported is cylindrical form (Hydra) and medusa is
by calcareous or siliceous 'spicules' or umbrella-like (Aurelia - Jelly fish).
proteinaceous 'spongin fibers'.
Umbrelar surface
Marginal lappet

Subumbrelar
surface

Oral arm Marginal tentacles

Aurelia
Fig. 4.6 Animal of Cnidaria

30

Body cavity is meant for circulation as Secretory (adhesive)
granules
well as digestion. Hence called gastrovascular Adhesive
granule
cavity or coelenteron.Tentacles bear cnidoblasts
Radiating fibre
or stinging cells which are meant for anchorage,
Covering cell
offence and defence. Cnidarians reproduce both

asexually and sexually. Asexually reproduction Spiral filament Nucleus Spiral
(nucleus) filament
takes place by budding and regeneration.
Synapse
Sexual reproduction takes place by gamete Straight filament Neuron
(nucleus)
formation. They exhibit alternation of polypoid Root

generation with medusoid generation. This Mesenchyme

phenomenon is called metagenesis i.e. polyps

produce medusae asexually and medusae Colloblast

produce polyps sexually. (e.g. Obelia)

Spines Thread tube
Stylet

Refractile rods Operculum

Lasso

Cytoplasm Pleurobrachia
Fig. 4.8 Animal of Ctenophora
Nucleus

Before discharge After discharge

Fig. 4.7 Cnidoblast 4. Phylum : Platyhelminthes
(platy -flat, helminth -worms)
Find out
Information about coral reef and sea fan. e.g. Planaria, Taenia (Tapeworm),

3. Phylum : Ctenophora Fasciola (Liver fluke).
e.g. Pleurobrachia, Ctenoplana.
These are commonly called comb jellies Body of these animals is dorso-
or sea walnuts. These are exclusively marine,
free swimming animals. Body is diploblastic, ventrally flattened, hence are called as flat
radially symmetrical with blind-sac body
plan. Animals have tissue-level organisation. worms. Animals are acoelomate, triploblastic
Locomotion is carried out by eight rows of
cilliated comb plates. Characteristic feature showing organ-system grade of organization.
of ctenophores is bioluminescence. Like
cnidarians, ctenophores also exhibit extra Mostly endoparasitic and few are free-living.
and intracellular digestion. Reproduction is
sexual with indirect development. Cnidoblasts Parasitic forms shows presence of hooks and
are absent hence these are called acnidarians.
Instead, they have colloblasts (sticky cells) to suckers for attachment to the body of host.
capture the prey. Ctenophora is represented by
very few members, hence it is considered as Body is covered by cuticle (in parasites) or
one of the minor phyla.
cilia (in free-living forms). Digestive system is

generally absent in parasitic forms, but in free-

living forms, it is incomplete (blind-sac plan).

Animals have flame cells or protonephridia,

helpful for excretion and osmoregulation.

Animals are hermaphrodite (bisexual). Self

fertilization is seen. Few have high power of

regeneration and show polyembryony.

31

Oral Mouth Pharynx Gastrovascular
Sucker
Head lobe Cavity Eyespots

Neck Immature
Sucker proglottid
hook
Mature
proglottid

Gravid
proglottid

a. Fasciola Ventral nerve cords c. Planaria

Excretory pore b. Taenia

Fig. 4.9 Animals of platyhelminthes

5. Phylum : Aschelminthes (ascus-sac, Anus Tail Mouth Dorsal lip
Tail Cloaca Ventral lip
helminth-worm) / Nemathelminthes
Head
(nema-thread) Male

e.g. Ascaris (Roundworm), Wuchereria Head

(filarial worm), Ancylostoma (hook worm).

These are mostly parasitic, few forms

are free-living. Body is long, cylindrical, thread Cuticle

like, circular in cross-section, hence are called a. Ascaris Female

round worms. They are triploblastic, bilaterally

symmetrical, pseudocoelmate, with tube within

tube body plan. Body is covered by tough and

resistant cuticle. Body wall has longitudinal

muscles but no circular muscles. Alimentary

canal is complete with mouth and anus at

opposite ends. Pharynx is well developed and

muscular. Excretion takes place by canals or b. Ancylostoma hookworm

gland cells. Excretory products are eliminated Fig. 4.11 Animals of Aschelminthes

through excretory pore. Nervous system has Can you tell?

nerve ring and nerves. Animals are unisexual 1. State parasitic adaptations in liverfluke
and Ascaris.
i.e. sexes are separate. Animals like Ascaris
2. Give example of free living platyhelminth.
shows sexual dimorphism. Usually female is
6. Phylum : Annelida (Annulus : Ring)
longer and broader and have straight posterior e.g. Nereis, Pheretima (Earthworm),
Hirudinaria (Leech).
end. Male is shorter and narrower and has They are commonly called ring worms
or segmented worms. Animals may be aquatic
curved posterior end with a pair of penial and few may be ectoparasitic or free living or
burrowing in moist soil. They show bilateral
setae for copulation. Fertilization is internal. symmetry with metameric segmentation.

Development may or may not include larval

stage. Tail Anal pore

Mouth

Sheath

Fig. 4.10 Wuchereria

32

A special region of the body called - This is largest phylum of kingdom
clitellum is present. Locomotion is with the animalia. These animals have jointed
help of longitudinal and circular muscles. appendages, hence the name -Arthropoda.
Locomotory structures like setae (earthworm), These are omnipresent and solitary or colonial,
parapodia (Nereis) or suckers (leech) are most of them are free-living (Barnacles are
present. Alimentary canal is complete. sedentary). Few are parasitic and sanguivorous
Exchange of gases takes place through body (female mosquito, bed bug). Their body
wall. Circulatory system is of closed type. is bilaterally symmetrical, triploblastic,
Excretion and osmoregulation is carried out eucoelomate, metamerically segmented with
with the help of nephridia. Nervous system tube within tube body plan and organ-system
consists of nerve ring and ventral nerve cord. level of organization. Body is covered by
Nerve cord is ventral, solid and ganglionated. tough, non-living chitinous exoskeleton. Hence,
Mostly hermaphrodites and few are dioecious they need periodic moulting (ecdysis). Body is
(Nereis). divided into head, thorax and abdomen.

a. Nereis a. Periplaneta b. Archispirostreptus

b. Hirudo c. Pheretima c. Hottentotta

Fig. 4.12 Animals of Annelida Fig. 4.13 Animals of Arthropoda

Alw ays Remembe r Digestive system is complete.
Circulatory system is of open type, blood flows
All animals from Annelida onwards through body cavity (haemocoel). Respiratory
are triploblastic, coelmate with organ system organs are gills, trachea, book lungs, book gills.
level of organization. Excretion takes by green glands, Malpighian
tubules or coxal glands. Nervous system is
1. Find out formed by nerve ring and double, ventral,
1. What are the merits and demerits of ganglionated nerve cord. Sense organs are
well developed in the form of antennae, simple
hermaphroditism? or compound eyes, various receptors. Sexes
2. Why are leeches used in Ayurveda? are separate showing sexual dimorphism,
3. What is the role of earthworms in fertilization is generally internal, development
is direct or indirect by metamorphosis. In some
agriculture? What is vermicompost? arthropods like honey bees, bugs etc. offsprings
are produced by parthenogenesis. Some insects
7. Phylum : Arthropoda (Arthros : Joint, exhibit polymorphism e.g. honey bee, ants,
Podos : leg) termites etc. Some arthropods are economically
important such as Apis (honey bees) for their
e.g. Cockroach, Butterfly, Scorpion, honey and wax.
Millipede , Prawn.

33

Lac is produced by Laccifer lacca (Lac Digestive system is well developed,
insect). Lobsters, prawns and crabs are edible, complete with anterior mouth and posterior
silk worms produce silk. Some arthropods are anus. Buccal cavity has a rasping organ called
harmful which acts as vector e.g. mosquito. radula which is provided with transverse rows
Locusta (locust) is a gregarious pest. Limulus of teeth. Aquatic forms show numerous feather
(King crab) is known as living fossil. like gills called ctenidia, useful for aquatic
respiration. Gills are present in mantle cavity.
1. Find out (space between visceral mass and mantle)
1. Why is phylum arthropoda considered as Terrestrial forms may show presence of lungs.
Circulatory system is of open type
most successful phylum? (except Sepia, which possesses closed type).
2. What do we mean by parthenogenesis? Blood contains a copper containing blue
3. What do we mean by living fossil? respiratory pigment called haemocyanin.
4. How the bees produce honey? Excretion occurs by kidneys, also called as organ
5. What will happen if arthropods do not of Bojanus. Nervous system is formed by three
pairs of ganglia. Ganglia are interconnected
moult? by commissures and connectives. Sense organs
such as eyes for vision, tentacles for tactile
8. Phylum : Mollusca (Mollis : soft) sensation, osphradia for testing purity of water
e.g. Pila, Bivalve, Octopus (devil fish), are present. Sexes are separate, animals are
Sepia (cuttle fish), Chaetopleura (Chiton), mostly oviparous, development is direct or
Pinctada (Pearl oyster), Loligo (Squid), Aplysia indirect.
(Sea hare), Dentalium (Tusk shell).
This is second largest phylum. Molluscs Economic importance - Pearl oyster
are either free living or sedentary. They are gives precious pearls. Many molluscs are
aquatic or seen in marshy places. Few are edible. Shells of molluscs are rich source of
terrestrial. These are soft bodied and show tube calcium.
within tube body plan. These are bilaterally
symmetrical, but few are asymmetrical due Can you tell?
to torsion (twisting). Body is divisible into
head, foot and visceral mass. Visceral mass 1. Explain the term metameric segmentation.
is enclosed in thick muscular fold of body 2. Give characteristics of Arthropoda.
wall called mantle. Mantle secretes a hard 3. Enlist harmful Arthropods.
calcareous shell, the shell may be external or 4. Why do Molluscs have shell?
internal or absent. Muscular foot is present on
ventral side.

a. Spisula b. Chaetopleura c. Pila
d. Sepia
e. Octopus

Fig. 4.14 Animals of Mollusca

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9. Phylum : Echinodermata Nervous system is simple with a nerve
(Echinus - Spines, derma - skin) ring around mouth and radial nerves in the
arms. Sexes are separate (sometimes bisexual),
e.g. Asterias (Sea star), Cucumaria (Sea fertilization is external, development is indirect.
cucumber), Echinus (Sea urchin), Antedon (sea They show high power of regeneration.
lily), Ophiothrix (Brittle star).
These are exclusively marine, solitary, 10. Phylum : Hemichordata (Hemi : Half,
sedentary or free-living and gregarious, Chordata : Rod)
benthic.
These are radially symmetrical e.g. Balanoglossus, Saccoglossus.
animals with pentamerous symmetry. Body Earlier, this Phylum was considered
may be spherical, elongated or star-shaped. as sub-phylum of Chordata because buccal
Endoskeleton is made up of calcareous ossicles. diverticulum was considered as notochord.
Spines are present on the body, hence the name But, now it is placed as a separate phylum of
echinodermata. The body is without definite Non-chordata. These are exclusively marine
body divisions, instead, there are two sides as animals, usually living at the bottom of sea in
oral and aboral. burrows. Mostly these are free living but the
The peculiar character is presence of animals like Rhabdopleura are sedentary. Body
water vascular system in which water enters is soft, vermiform, unsegmented and divided
through madreporite. This system is used into three parts - proboscis, collar and trunk.
in locomotion, food capturing, respiration, Buccal cavity gives rise to rod-like buccal
etc. Digestive system is complete. Mouth is diverticulum which is considered as notochord
ventrally present on oral surface and anus on by some scientists.
aboral surface.
Respiration is performed by peristomial Proboscis
gills, papillae, respiratory tree, etc. Circulatory
system and excretory system is absent. Anus

Collar

Branchial region

a. Antedon b. Ophiothrix Genital region
Hepatic region

a. Balanoglossus

c. Asterias d. Cucumaria b. Saccoglossus
Fig. 4.16 Animals of Hemichordata
Fig. 4.15 Animals of Echirodemata

35

Alimentary canal is complete, straight 11. Phylum : Chordata
or 'U' shaped. Respiration occurs by numerous Chordates are characterised by
gills, arranged in two longitudinal rows, presence of cartilagenous notochord at least
present in the pharyngeal region. Gills open by in early embryonic life, presence of gill slits
gill slits. in the pharyngeal (neck) region, presence of
Circulatory system is simple and hollow, dorsal nerve cord running through out
open type. Excretion occurs with the help of the length of body and ventral heart.
glomerulus. Nervous tissue is embedded in Phylum Chordata is divided into three
epidermis on both dorsal and ventral sides. subphyla-Urochordata, Cephalochordata and
The sexes are separate (sometimes bisexual). Vertebrata. Urochordata and Cephalochordata
Fertilization is external and development is are collectively called Protochordates.
indirect through free swimming larva. This
phylum is the connecting link between non- a. Subphylum : Urochordata or Tunicata
chordata and chordata. e.g. Herdmania, Salpa, Doliolum.
These are also called as tunicates or
Can you tell? ascidians. They are exclusively marine. Body
is soft and covered by 'test' or 'tunic' which is
1. Give salient features of Phylum made up of tunicine. Notochord is present only
Echinodermata. in the tail of larva, hence the name, urochordata.
Notochord is lost during metamorphosis.
2. Hemichordata is the connecting link Pharynx has many gill slits. Closed circulatory
between non-chordata and chordata. system is present. Development is indirect.
Give reasons.

Observe and Discuss

Compare and contrast between
Chordates and Non-chordates.

Non-Chordate Exoskeleton Pulsating dorsal
blood vessel

Nerve cord Digestive tube Anus a. Herdmania b. Ascidia
Chordate Notochord
Fig. 4.17 Animals of Urochordata

Gill slits Heart Anus Post-anal tail b. Subphylum : Cephalochordata
e.g. Branchiostoma (Amphioxus or Lancelet)
F ind ou t Why Balanoglossus They are exclusively marine. These are
is considered as connecting link between also called as lancelet, which are small fish
Non-Chordates and Chordates? like animals that rarely exceed 5 cm in length.

D o yo u know ? Notochord is Lancelets partly live burried in
flexible rod-like structure of vacuolated cells. soft marine sediments. Notochord extends
It is located along the dorsal side of chordate throughout the length of body and present
embryos. It gives support to the body and throughout the life. Myotomes (muscle blocks)
provides attachment to muscles. are present. Post-anal tail is present. Closed
circulatory system is present. Blood is without
pigment.

36

Buccal cirri Notochord Digestive system lacks stomach.
Vestibule Dorsal hollow Respiration occurs by 6 to 15 pairs of gills slits.
nerve cord Gills slits are without operculum. Heart is two
Pharynx chambered with one auricle and one ventricle.
Gill slits Midgut Gonad is single, large and without gonoduct.
Fertilization is external. They are anadromous
Midgut diverticulum i.e. migrate for spawning to fresh water from
Atriopore their marine habitat. After spawning, they die
Myotomes within few days. Larvae metamorphose and
Anus then migrate to ocean.

Amphioxus Caudal fin Can you tell?

Fig. 4.18 Animal from Cephalochordata 1. Herdmania is called a Chordate. Explain.
2. Give characteristics of Petromyzon.
c. Subphylum : Vertebrata
In these chordates, notochord is replaced Comment on its mode of nutrition.
by cartilaginous or bony vertebral column. It is
divided into two divisions - Agnathostomata 2. Division : Gnathostomata
(no jaws) and Gnathostomata (jaws present). It is divided into two superclasses -
Pisces (bear fins) and tetrapoda (bear four
1. Division : Agnathostomata limbs).
This division includes the lowest or
most primitive vertebrates, which are without A. Superclass : Pisces
jaws. They include only one class of living These are aquatic animals. These are
vertebrates - the Cyclostomata. poikilothermic (body temperature changes
according to the change in surrounding
Class : Cyclostomata (Cyclos : Circular, Stoma temperature). Lateral line system is present
- mouth) Lat/Grk. which shows presence of rheoreceptores for
e.g. Petromyzon (Lamprey), Myxine (Hagfish). detection of water current. Locomotion is
Cyclostomes are jawless and eel- by body muscles and fins. Caudal fin acts as
like animals. Skin is soft, smooth containing steering wheel. Exoskeleton is of dermal scales.
unicellular mucus glands, but no scales. Median Endoskeleton is either bony or cartilagenous.
fins are present but paired fins are absent. Body is streamlined and boat shaped. This
They are ectoparasites. They have sucking feature offers minimum resistance during
and circular mouth without jaws. Cranium and swimming. Respiration is by gills. Heart is two
vertebral column made up of cartilage. chambered and is ventral in position. It shows
single and closed circulation. Heart always
Sea lamprey shows presence of deoxygenated blood, so it
is described as venous heart. They have well
Detail of mouth developed brain with large olfactory lobes.
Sexes are separate. Most fishes are oviparous
Fig 4.19 Petromyzon and some are viviparous.
Superclass Pisces is divided into two
classes as below.

1. Class Chondrichthyes :
(chondron : cartilage, ichthyes : fish)

e.g. Scoliodon (Dog fish), Pristis
(Sawfish), Electric ray, Common skate,
Hammer headed shark.

37

Carcanodon (great white shark), Trygon Exocoetus (flying fish), Hippocampus
(Sting ray) (sea-horse), Pomphret, Labeo rohita (Rohu),
Catla (Katla), Clarias (Magur), Aquarium
Dorsal fin Lateral line fishes. Betta -(fighting fish), Pterophyllum
Eye (Angle fish).
Osteichthyes includes fishes in which
Mouth Caudal fin bony endoskeleton is present, hence called as
bony fishes. These are aquatic, present in both
Gill clefts Pelvic fin fresh and marine waters. Exoskeleton is formed
Median ventral fin of cycloid and ctenoid scales. Mouth is mostly
terminal in position. Tail fin is formed by two
a. Scoliodon equal lobes i.e. homoceral (symmetrical). Four
pairs of gill slits are present, covered with
operculum. Air bladder is present to maintain
buoyancy. Claspers are absent. Fertilization is
external. These fishes are oviparous.

b. Anoxypristis Operculum Dorsal fin
Eye
Fig 4.20 Animals from chondrichthyes
Forked tail
Chondrichthyes includes the animals
in which endoskeleton is cartilagenous. These Mouth Ventral fin Pelvic fin
are exclusively marine. Exoskeleton is formed Pectoral fin
of placoid scales. Teeth are modified placoid a. Catla
scales which are backwardly directed. Mouth
is ventral in position. 2 pairs of lateral fins b. Exocoetus c. Hippocampus
(pectoral and Pelvic). Caudal fin is heterocercal (flying fish) (sea-horse)
(Asymmetrical). Five to seven pairs of gill slits
are present. They are not covered by operculum. Fig 4.21 Animals from Osteichthyes
Air bladder is absent hence these fishes need
to swim constantly so that they do not sink. Can you tell?
They are predatory fishes. Some of them have
electric organs e.g. Torpedo - (electric ray) and 1. Differentiate between Chondrichthyes
some have poison sting e.g. Trygon - (sting and Osteichthyes on the basis of scales
ray) as organs of offence ans defence. Male and caudal fin.
copulatory organs called claspers are present.
Fertilization is internal. Many of them are 2. What is the lateral line system?
viviparous. 3. Why Piscian heart is called a venous

2. Class : Osteichthyes heart?
(Osteon : bone , ichthyes : fish)

e.g. Bombay duck, Lung fishes
(Protopterus, Lepidosiren)

38

B. Superclass : Tetrapoda 2. Class : Reptilia
These animals bear two pairs of (Repere : to creep or to crawl)
appendages. Some animals like snakes are
secondarily limbless. e.g. Naja naja (Cobra), Hemidactylus
Superclass tetrapoda includes four (Wall lizard), Chelonia ( Turtle), Crocodilus
classes namely, Amphibia, Reptilia, and (Crocodile), Testudo (Tortoise), Chameleon
Mammalia. (Tree lizard), Bangarus (Krait), Vipera (viper).

1. Class : Amphibia a. Lizard
(Amphi : both, bias : life)
b. Crocodile
e.g. Rana (Frog), Bufo (Toad), Salamandra
(Salamander), Ichthyophis (Limbless c. Tortoise
amphibian), Hyla (Tree frog).
Amphibia include the animals which Fig 4.23 Animals from Reptilia
live on land as well as in water (fresh water
only). They are poikilothermic animals. Body Reptilia includes crawling animals.
is differentiated into head and trunk. Neck These are the first true terrestrial vertebrates.
and tail is usually absent in many adults with Few may be aquatic or semi-aquatic, also
few exceptions. Two pairs of limbs arise from found in marshy area. Locomotion occurs by
pectoral and pelvic girdles respectively. These limbs. The limbs are pentadactyl and digits
help in locomotion. Skin is moist, glandular bear claws. Limbs help the animal to walk or
with mucous glands. Exoskeleton is absent. creep. Snakes are limbless. Snakes crawl on
Eyelids are present. Tympanum represents the their belly. Reptiles are poikilotherms. Skin is
ear. Excretory products, digestive wastes and dry, non-glandular and covered by exoskeleton
gametes are released through common chamber of epidermal scales or scutes, shields or plates.
called cloaca. Circulatory system is of closed Lizards and snakes shed their skin periodically.
type. Heart is three chambered and ventral in Tympanum is present. Heart has two complete
position. RBCs are biconvex and nucleated. auricles, but ventricles are incompletely
Respiration is by skin, lungs and buccopharynx. partitioned. So heart is not perfectly four
Nervous system is well developed. Sexes are chambered (except crocodile). Brain is well
separate. These are oviparous. Fertilization developed. The olfactory lobes and cerebellum
is external. Development is indirect through are better developed than those of amphibians.
aquatic larval stage.They show metamorphosis. Sexes are separate and show prominent sexual
dimorphism. Fertilization is internal. They are
a. Anura b. Bufo oviparous (except viper, it is viviparous) and
c. Salamander show parental care. .

Fig 4.22 Animals from Amphibia

39

Can you tell? Body is differentiated into head, neck,
1. Amphibians do not have exoskeleton. trunk and tail. Skin is thin, dry, non-glandular
except oil gland at the base of tail (uropygial
Give reason. gland). Bones are hollow (pneumatic) with
2. Why are amphibians and reptilians called air cavities to reduce body weight. Jaws are
without teeth and modified into beak. Crop
poikilotherms? and gizzard are present in digestive system.
3. Class : Aves (Avis : bird) Blood is red in colour due to presence of red
e.g. Columba (Pigeon), Psittacula blood cells. RBCs are biconvex and nucleated.
(Parrot), Flight less birds like Struthio (ostrich), Heart is perfectly four chambered. They show
Kiwi, Aptenodytes (Penguin), Corvus (crow), double circulation. Respiration takes place by
Neophron (Vulture), Passer (sparrow). lungs, having air sacs to increase the buoyancy.
Brain is enlarged and has well developed
a. Strythio cerebellum for equillibrium. Sexes are separate
with prominent sexual dimorphism. These are
b. Passer oviparous. Fertilization is internal. Parental
care is very well developed. Seasonal migration
c. Psittacoidea is seen in some birds.

Special features :- The urinary bladder is
absent. The female shows presence of only left
ovary and left oviduct. This helps to reduce
body weight.

d. Necrosyrtes 4. Class : Mammalia (mammae :
breasts, nipples)
e. Pavo
Fig 4.24 Aves e.g. Bat, Rattus (Rat), Macaca (Monkey),
Forelimbs are modified into wings for Camelus (Camel), Whale, Human being,
flying (some birds have lost the capacity to fly Cannis (dog), Felis (Cat), Elephas (Elephant),
e.g. Ostrich), hind limbs are used for walking, Equus (Horse), Pteropus (flying fox).
clasping tree branches and running. Aquatic Oviparous - Ornithorhynchus (Platypus).
birds have webs between their toes (e.g. Duck). Viviparous - Macropus (Kangaroo).
Body is streamlined (Boat shaped) to reduce Mammalia includes the animals having
resistance during flight. These are homeotherms mammary glands (milk producing glands)
i.e. their body temperature remains constant. for the nourishment of young ones. These
Exoskeleton is made up of feathers. Scales are are omnipresent. Mostly terrestrial, some
present on hind limbs. are aquatic and few are aerial and arboreal.
Limbs are the organs of locomotion and used
for walking, flying, climbing, burrowing,
swimming, etc. Body is differentiated into head,
neck, trunk and tail. These are homeotherms.
Exoskeleton is in the form of hair, fur, nails,
hooves, horns, etc. Skin is glandular having
sweat glands and sebaceous glands (oil glands).
Mammary glands are modified sweat glands.

40

They have external ear (pinna). They d. Macropus
show heterodont dentition. RBCs are biconcave
and enucleated. Blood is red in colour. Heart
is ventral in position and four chambered.
Respiration takes place by lungs. Brain is highly
developed. Cerebrum shows a transverse band
called corpus callosum. Few mammals are
oviparous (e.g. Duck billed platypus). Some
have pouches for the development of immature
young ones, these are called marsupials e.g.
Kangaroo. Majority of mammals are placental
and viviparous.

a. Camelus b. Ornithorhynchus c. Trachypithecus
Fig 4.25 Mammals

Can you tell?
1. Give adaptations in aves for flying.
2. Aves and mammals are homeotherms. Give reason.
3. How mammals differ from other groups of animals.

Do yourself

Observe different animals in your surrounding, write detailed classification and
write down the characteristics of animals in following format.

Picture / Photograph Classification Characteristics

41