NCERT Class 11 Biology - Part 1

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UNIT ONE

DIVERSITY IN THE LIVING WORLD

Biology is the science of life forms and living processes. The living world comprises an amazing diversity of living organisms. Early man could easily perceive the difference between inanimate matter and living organisms. Early man deified some of the inanimate matter (wind, sea, fire, etc.) and some among the animals and plants. A common feature of all such forms of inanimate and animate objects was the sense of awe or fear that they evoked. The description of living organisms including human beings began much later in human history. Societies which indulged in anthropocentric view of biology could register limited progress in biological knowledge. Systematic and monumental description of life forms brought in, out of necessity, detailed systems of identification, nomenclature and classification. The biggest spin off of such studies was the recognition of the sharing of similarities among living organisms both horizontally and vertically. That all present day living organisms are related to each other and also to all organisms that ever lived on this earth, was a revelation which humbled man and led to cultural movements for conservation of biodiversity. In the following chapters of this unit, you will get a description, including classification, of animals and plants from a taxonomist's perspective.

Born on fifth July nineteen oh four, in Kempten, Germany, Ernst Mayr, the Harvard University evolutionary biologist who has been called 'The Darwin of the twentieth century', was one of the one hundred greatest scientists of all time. Mayr joined Harvard's Faculty of Arts and Sciences in nineteen fifty-three and retired in nineteen seventy-five, assuming the title Alexander Agassiz Professor of Zoology Emeritus. Throughout his nearly eighty-year career, his research spanned ornithology, taxonomy, zoogeography, evolution, systematics, and the history and philosophy of biology. He almost single-handedly made the origin of species diversity the central question of evolutionary biology that it is today. He also pioneered the currently accepted definition of a biological species. Mayr was awarded the three prizes widely regarded as the triple crown of biology: the Balzan Prize in nineteen eighty-three, the International Prize for Biology in nineteen ninety-four, and the Crafoord Prize in nineteen ninety-nine. Mayr died at the age of one hundred in the year two thousand four.

One point one. What is 'Living'?

One point two. Diversity in the Living World

One point three. Taxonomic Categories

One point one. WHAT IS 'LIVING'?

One point two. Diversity in the living world

BIOLOGY

One point three TAXONOMIC CATEGORIES

One point three point one Species

One point three point two Genus

One point three point three Family

BIOLOGY

One point three point five Class

One point three point six Phylum

One point three point seven Kingdom

One point four TAXONOMICAL AIDS

One point four point one Herbarium

One point four point two Botanical Gardens

One point four point three Museum

One point four point four Zoological Parks

One point four point five Key

BIOLOGY

SUMMARY

EXERCISES

CHAPTER TWO

Two point one KINGDOM MONERA

Two point one point one Archaebacteria

Two point one point two Eubacteria

Two point two. KINGDOM PROTISTA

Two point two point one. Chrysophytes

Two point two point two. Dianoflagellates

Two point two point three. Euglenoids

Two point two point four. Slime Moulds

Two point two point five. Protozoans

Two point three. KINGDOM FUNGI

Two point three point one Phycomycetes

Two point three point two Ascomycetes

Two point three point three Basidiomycetes

Two point three point four Deuteromycetes

BIOLOGICAL CLASSIFICATION

Two point five KINGDOM ANIMALIA

Two point six. Viruses, Viroids and Lichens

Biological Classification

Summary

Exercises

Three point one. Algae

Three point three. Pteridophytes Three point four. Gymnosperms Three point five. Angiosperms

CHAPTER THREE PLANT KINGDOM

Three point one. ALGAE

PLANT KINGDOM

Three point one point one. Chlorophyceae

Three point one point two. Phaeophyceae

PLANT KINGDOM

Three point one point three Rhodophyceae

Three point two BRYOPHYTES

PLANT KINGDOM

Three point two point one Liverworts

Three point two point two Mosses

Three point three PTERIDOPHYTES

PLANT KINGDOM

Three point four GYMNOSPERMS

PLANT KINGDOM

Three point five ANGIOSPERMS

PLANT KINGDOM

Three point six PLANT LIFE CYCLES AND ALTERNATION OF GENERATIONS

PLANT KINGDOM

SUMMARY

EXERCISES

PLANT KINGDOM

Four point one Basis of Classification

CHAPTER FOUR

Four point one BASIS OF CLASSIFICATION

Four point one point one Levels of Organisation

Four point one point two Symmetry

Four point one point three Diploblastic and Triploblastic Organisation

Four point one point four Coelom

Four point one point five Segmentation

Four point one point six Notochord

Four point two Classification of Animals

Animal Kingdom

Four point two point one Phylum - Porifera

Four point two point two Phylum - Coelenterata (Cnidaria)

Four point two point three. Phylum - Ctenophora

Four point two point four. Phylum - Platyhelminthes

Four point two point five. Phylum - Aschelminthes

Four point two point six. Phylum - Annelida

Four point two point seven. Phylum - Arthropoda

Four point two point eight. Phylum - Mollusca

Four point two point nine. Phylum - Echinodermata.

Four point two point ten Phylum - Hemichordata

Four point two point eleven Phylum - Chordata

Subphyla

Four point two point eleven point one Class - Cyclostomata

Four point two point eleven point two Class - Chondrichthyes

Four point two point eleven point three Class - Osteichthyes

Four point two point eleven point four Class - Amphibia

Four point two point eleven point five Class - Reptilia

Four point two point eleven point six Class - Aves

Four point two point eleven point seven Class - Mammalia

SUMMARY

EXERCISES

Fifteen. Prepare a list of some animals that are found parasitic on human beings.

STRUCTURAL ORGANISATION IN PLANTS AND ANIMALS

Five point three. The Leaf Five point four. The Inflorescence Five point five. The Flower

Five point nine. Description of Some Important Families

M LORPHOLOGY OF FLOWERING PLANTS

Five point one. THE ROOT

MORPHOLOGY OF FLOWERING PLANTS

Five point one point two. Modifications of Root

Five point two. THE STEM

Five point two point one. Modifications of Stem

Five point three. THE LEAF

Five point three point one. Venation

Five point three point two Types of Leaves

MORPHOLOGY OF FLOWERING PLANTS

Five point three point three Phyllotaxy

Five point three point four Modifications of Leaves

Five point four THE INFLORESCENCE

Five point five THE FLOWER

Five point five point one. Parts of a Flower

Five point five point one point one. Calyx

Five point five point one point two. Corolla

MORPHOLOGY OF FLOWERING PLANTS

Five point five point one point four. Gynoecium

Five point six. The Fruit

Five point seven. The Seed

Five point seven point one. Structure of a Dicotyledonous Seed

MORPHOLOGY OF FLOWERING PLANTS

Five point seven point two Structure of Monocotyledonous Seed

Five point eight SEMI-TECHNICAL DESCRIPTION OF A TYPICAL FLOWERING PLANT

Five point nine DESCRIPTION OF SOME IMPORTANT FAMILIES

Vegetative Characters

Floral characters

Economic importance

Five point nine point two Solanaceae

Vegetative Characters

Floral Characters

Economic Importance

MORPHOLOGY OF FLOWERING PLANTS

Floral characters

Economic Importance

SUMMARY

EXERCISES

MORPHOLOGY OF FLOWERING PLANTS

Six. Three Anatomy of Dicotyledonous and Monocotyledonous Plants

CHAPT HAPTER Six

Six. One THE TISSUES

Six. One point one Meristematic Tissues

Six point one point two Permanent Tissues

Six point one point two point one Simple Tissues

ANATOMY OF FLOWERING PLANTS

Six point one point two point two Complex Tissues

Six point two. The Tissue System

Six point two point one. Epidermal Tissue System

Six point two point two. The Ground Tissue System

Six point two point three. The Vascular Tissue System

Six point three. Anatomy of Dicotyledonous and Monocotyledonous Plants

Six point three point one. Dicotyledonous Root

Anatomy of Flowering Plants

Six point three point two Monocotyledonous Root

Six point three point three Dicotyledonous Stem

ANATOMY OF FLOWERING PLANTS

Six point three point four Monocotyledonous Stem

Six point three point five Dorsiventral (Dicotyledonous) Leaf

Six point three point six Isobilateral (Monocotyledonous) Leaf

Six point four SECONDARY GROWTH

Six point four point one Vascular Cambium

Six point four point one point two Activity of the cambial ring

Six point four point one point three. Spring wood and autumn wood

Six point four point one point four. Heartwood and sapwood

Six point four point two. Cork Cambium

ANATOMY OF FLOWERING PLANTS

Six point four point three. Secondary Growth in Roots

SUMMARY

EXERCISES

Seven point two Organ and Organ System

CHAPTER HAPTER

Seven point one ANIMAL TISSUES

Seven point one point one Epithelial Tissue

Seven point one point two Connective Tissue

Seven point one point three Muscle Tissue

Seven point one point four Neural Tissue

Seven point two Organ and Organ System

Seven point three EARTHWORM

Seven point three point one Morphology

Seven point three point two Anatomy

Seven point four COCKROACH

Seven point four point one Morphology

Overview

This educational material explores the concept of life and biodiversity, outlining the classification systems for living organisms and the significance of understanding their diversity. It provides a comprehensive introduction to biology as a discipline.

Key Points

1Biology is the study of life forms and their processes
2Living organisms share similarities that reflect evolutionary relationships
3Classification systems help standardize the naming of organisms globally
4Key features of living organisms include growth, reproduction, and metabolism
5Biodiversity encompasses millions of species around the world.

Details

Category: Biology and Natural Sciences

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