, NCERT BIOLOGY
SHORT NOTES
FUTUREDOCTOREDUCATION.COM
CLASS XI & XII
,Life is a unique, complex organization of molecules, expressing through chemical reactions which lead to growth,
development, responsiveness, adaptation & reproduction.
A living organism is self-replicating, evolving and self-regulating interactive system capable of responding to external stimuli.
PROPERTIES OF LIVING ORGANISMS
1. Growth 3. Metabolism
• It is the increase in number & mass of cells by cell division. • It is the sum total of all biochemical reactions taking place
• In plants, growth continues throughout their lifespan. inside a living system.
• In animals, growth is only up to a certain age. However, • It is the defining feature of living organisms.
cell division occurs to replace lost cells. • Metabolic reactions can be demonstrated outside the body
• Basically, growth is the increase in mass & size. Thus non- in cell-free systems. Isolated metabolic reactions in vitro
living objects also grow (surface accumulation of material). are not living things but are living reactions.
So growth is not a defining property of living organisms.
4. Cellular organization
• In living organisms, growth is from inside.
• Organisms are made up of one or more cells.
2. Reproduction • It is the defining feature of living organisms.
• It is the production of progeny having features similar to
5. Consciousness
those of parents.
• Organisms reproduce asexually and sexually. • It is the ability of organisms to sense their environment and
• In unicellular organisms, growth & reproduction are same respond to environmental stimuli (like light, water,
because they reproduce by cell division. temperature, other organisms, chemicals, pollutants, etc).
• Many organisms do not reproduce (e.g. mules, worker • All organisms are ‘aware’ of their surroundings. So, it is the
bees, infertile human couples, etc). Hence, reproduction is defining property of living organisms.
not a perfect defining property of living organisms. • Human is the only organism having self-consciousness.
DIVERSITY IN THE LIVING WORLD
• The number and types of organisms present on earth refer • The first word is genus name (Generic name) and second
to biodiversity. word is the species name (specific epithet).
• Number of species described is 1.7-1.8 million. E.g. Homo sapiens- Homo represents the genus name and
• Taxonomy is the study of identification, classification & sapiens represents the species name.
nomenclature of organisms. • The Genus name starts with capital letter and the species
Systematics (Latin ‘systema’ = systematic arrangement) name starts with small letter.
deals with evolutionary relationships among organisms. • Name of the author (in abbreviated form) appears at the end
• Systema Naturae is the book written by Linnaeus. of the biological name.
Basic processes of taxonomy E.g., Mangifera indica Linn. It indicates that this species
• Characterization: It is the understanding of characters of was first described by Linnaeus.
organisms such as external and internal structure, structure of TAXONOMIC CATEGORIES
cell, development process, ecological information etc. - Classification involves hierarchy of steps in which each
• Identification: It is the correct description of the organism step represents a taxonomic category (rank).
so that the naming is possible. - All categories together constitute a taxonomic hierarchy.
• Classification: It is the grouping of organisms into - A group of organisms occupying a particular category is
convenient categories (taxa) based on characters. called a taxon (pl. taxa). E.g. Class Mammalia.
• Nomenclature (naming): It is the standardization of
- Each category or taxon represents a unit of classification.
names of the organisms such that an organism is known by Category Taxon
the same name all over the world. Kingdom Animalia
The system of naming with two components is called ↑ ↑
Binomial nomenclature. It is proposed by Linnaeus. Phylum/Division Chordata
Taxonomic ↑ ↑
Botanical names are based on the rules in International Class Mammalia
hierarchy in
Code for Botanical Nomenclature (ICBN). ↑ ↑
ascending order
Zoological names are based on International Code for Order Primata
↑ ↑
Zoological Nomenclature (ICZN). Family Hominidae
↑ ↑
Universal rules of Binomial nomenclature Genus Homo
• Scientific names are in Latin or Latinised and written in ↑ ↑
Species Sapiens
italics. When handwritten, they are underlined separately.
1
, Species: It is a group of closely related organisms capable of Family: It is a group of closely related genera. E.g.
interbreeding to produce fertile offspring. Family Solanaceae includes Genus Solanum, Genus
It is the lowest category. E.g. Petunia and Genus Datura.
Family Felidae includes Genus Panthera and Genus Felis.
Common name Generic name Specific epithet
Mango Mangifera indica Order: It is the assemblage of related families. E.g.
Potato Solanum tuberosum Order Polymoniales includes Family Convolvulaceae and
Nightshade Solanum nigrum Family Solanaceae.
Tomato Solanum lycopersicum Order Carnivora includes Family Felidae & Family Canidae.
Brinjal Solanum melongena Class: It is the assemblage of related orders. E.g.
Lion Panthera leo Order Primata, Carnivora etc. is placed in class Mammalia.
Tiger Panthera tigris Phylum (Division in case of plants): It is the assemblage of
Leopard Panthera pardus
related classes.
Modern man Homo sapiens
E.g. Classes Amphibia, Reptilia, Aves, Mammalia etc.
Genus: It is the aggregates of closely related species. come under phylum Chordata.
E.g. Potato, tomato & brinjal are species of genus Solanum. Kingdom: The assemblage of related phyla. It is the highest
Lion, leopard & tiger are species of genus Panthera. This category. E.g. Kingdom Plantae, Kingdom Animalia etc.
genus differs from genus Felis (genus of cats).
Organisms with their taxonomic categories
Common name Man Housefly Mango Wheat
Biological name Homo sapiens Musca domestica Mangifera indica Triticum aestivum
Species sapiens domestica indica aestivum
Genus Homo Musca Mangifera Triticum
Family Hominidae Muscidae Anacardiaceae Poaceae
Order Primata Diptera Sapindales Poales
Class Mammalia Insecta Dicotyledonae Monocotyledonae
Phylum/Division Chordata Arthropoda Angiospermae Angiospermae
Kingdom Animalia Animalia Plantae Plantae
TAXONOMICAL AIDS
a. Herbarium Stuffed larger animals like birds and mammals.
- It is a store house (repository) of plant specimens that are Collections of animal skeletons.
dried, pressed and preserved on sheets and are arranged d. Zoological Parks (Zoos)
according to universally accepted classification. - These are the places where live wild animals are kept in
- Herbarium sheets are labelled with information about date protected environments under human care.
and place of collection, English, local and botanical names, - It helps to learn about their food habits and behaviour.
family, collector’s name etc.
e. Key
b. Botanical gardens
- It is an analytical method of identification of organisms
- These are specialized gardens having collections of living based on similarities and dissimilarities.
plants for reference and identification. - It is based on the contrasting characters generally in a pair
- Each plant is labelled with its botanical name and family. called couplet.
- Famous botanical gardens: - Each couplet has two opposite options. Of these, only
o Royal Botanical Garden at Kew (England). relevant option is accepted and other is rejected.
o Indian Botanical Garden, Howrah (India).
- Each statement in the key is called a lead.
o At National Botanical Research Institute, Lucknow (India).
c. Biological Museum Flora, manuals, monographs & catalogues
- It is a collection of preserved plants and animals for study - Flora: Actual account of habitat and distribution of plant
and reference. species of a given area.
- A museum contains - Manuals: The record that contains information for
Specimens preserved in preservative solutions in identification of names of species found in an area.
containers or jars. - Monographs: The records that contain information on any
Preserved dry specimens of plants and animals. one taxon.
Insects preserved in insect boxes after collecting, killing - Catalogue: Alphabetical list of species.
and pinning.
2
SHORT NOTES
FUTUREDOCTOREDUCATION.COM
CLASS XI & XII
,Life is a unique, complex organization of molecules, expressing through chemical reactions which lead to growth,
development, responsiveness, adaptation & reproduction.
A living organism is self-replicating, evolving and self-regulating interactive system capable of responding to external stimuli.
PROPERTIES OF LIVING ORGANISMS
1. Growth 3. Metabolism
• It is the increase in number & mass of cells by cell division. • It is the sum total of all biochemical reactions taking place
• In plants, growth continues throughout their lifespan. inside a living system.
• In animals, growth is only up to a certain age. However, • It is the defining feature of living organisms.
cell division occurs to replace lost cells. • Metabolic reactions can be demonstrated outside the body
• Basically, growth is the increase in mass & size. Thus non- in cell-free systems. Isolated metabolic reactions in vitro
living objects also grow (surface accumulation of material). are not living things but are living reactions.
So growth is not a defining property of living organisms.
4. Cellular organization
• In living organisms, growth is from inside.
• Organisms are made up of one or more cells.
2. Reproduction • It is the defining feature of living organisms.
• It is the production of progeny having features similar to
5. Consciousness
those of parents.
• Organisms reproduce asexually and sexually. • It is the ability of organisms to sense their environment and
• In unicellular organisms, growth & reproduction are same respond to environmental stimuli (like light, water,
because they reproduce by cell division. temperature, other organisms, chemicals, pollutants, etc).
• Many organisms do not reproduce (e.g. mules, worker • All organisms are ‘aware’ of their surroundings. So, it is the
bees, infertile human couples, etc). Hence, reproduction is defining property of living organisms.
not a perfect defining property of living organisms. • Human is the only organism having self-consciousness.
DIVERSITY IN THE LIVING WORLD
• The number and types of organisms present on earth refer • The first word is genus name (Generic name) and second
to biodiversity. word is the species name (specific epithet).
• Number of species described is 1.7-1.8 million. E.g. Homo sapiens- Homo represents the genus name and
• Taxonomy is the study of identification, classification & sapiens represents the species name.
nomenclature of organisms. • The Genus name starts with capital letter and the species
Systematics (Latin ‘systema’ = systematic arrangement) name starts with small letter.
deals with evolutionary relationships among organisms. • Name of the author (in abbreviated form) appears at the end
• Systema Naturae is the book written by Linnaeus. of the biological name.
Basic processes of taxonomy E.g., Mangifera indica Linn. It indicates that this species
• Characterization: It is the understanding of characters of was first described by Linnaeus.
organisms such as external and internal structure, structure of TAXONOMIC CATEGORIES
cell, development process, ecological information etc. - Classification involves hierarchy of steps in which each
• Identification: It is the correct description of the organism step represents a taxonomic category (rank).
so that the naming is possible. - All categories together constitute a taxonomic hierarchy.
• Classification: It is the grouping of organisms into - A group of organisms occupying a particular category is
convenient categories (taxa) based on characters. called a taxon (pl. taxa). E.g. Class Mammalia.
• Nomenclature (naming): It is the standardization of
- Each category or taxon represents a unit of classification.
names of the organisms such that an organism is known by Category Taxon
the same name all over the world. Kingdom Animalia
The system of naming with two components is called ↑ ↑
Binomial nomenclature. It is proposed by Linnaeus. Phylum/Division Chordata
Taxonomic ↑ ↑
Botanical names are based on the rules in International Class Mammalia
hierarchy in
Code for Botanical Nomenclature (ICBN). ↑ ↑
ascending order
Zoological names are based on International Code for Order Primata
↑ ↑
Zoological Nomenclature (ICZN). Family Hominidae
↑ ↑
Universal rules of Binomial nomenclature Genus Homo
• Scientific names are in Latin or Latinised and written in ↑ ↑
Species Sapiens
italics. When handwritten, they are underlined separately.
1
, Species: It is a group of closely related organisms capable of Family: It is a group of closely related genera. E.g.
interbreeding to produce fertile offspring. Family Solanaceae includes Genus Solanum, Genus
It is the lowest category. E.g. Petunia and Genus Datura.
Family Felidae includes Genus Panthera and Genus Felis.
Common name Generic name Specific epithet
Mango Mangifera indica Order: It is the assemblage of related families. E.g.
Potato Solanum tuberosum Order Polymoniales includes Family Convolvulaceae and
Nightshade Solanum nigrum Family Solanaceae.
Tomato Solanum lycopersicum Order Carnivora includes Family Felidae & Family Canidae.
Brinjal Solanum melongena Class: It is the assemblage of related orders. E.g.
Lion Panthera leo Order Primata, Carnivora etc. is placed in class Mammalia.
Tiger Panthera tigris Phylum (Division in case of plants): It is the assemblage of
Leopard Panthera pardus
related classes.
Modern man Homo sapiens
E.g. Classes Amphibia, Reptilia, Aves, Mammalia etc.
Genus: It is the aggregates of closely related species. come under phylum Chordata.
E.g. Potato, tomato & brinjal are species of genus Solanum. Kingdom: The assemblage of related phyla. It is the highest
Lion, leopard & tiger are species of genus Panthera. This category. E.g. Kingdom Plantae, Kingdom Animalia etc.
genus differs from genus Felis (genus of cats).
Organisms with their taxonomic categories
Common name Man Housefly Mango Wheat
Biological name Homo sapiens Musca domestica Mangifera indica Triticum aestivum
Species sapiens domestica indica aestivum
Genus Homo Musca Mangifera Triticum
Family Hominidae Muscidae Anacardiaceae Poaceae
Order Primata Diptera Sapindales Poales
Class Mammalia Insecta Dicotyledonae Monocotyledonae
Phylum/Division Chordata Arthropoda Angiospermae Angiospermae
Kingdom Animalia Animalia Plantae Plantae
TAXONOMICAL AIDS
a. Herbarium Stuffed larger animals like birds and mammals.
- It is a store house (repository) of plant specimens that are Collections of animal skeletons.
dried, pressed and preserved on sheets and are arranged d. Zoological Parks (Zoos)
according to universally accepted classification. - These are the places where live wild animals are kept in
- Herbarium sheets are labelled with information about date protected environments under human care.
and place of collection, English, local and botanical names, - It helps to learn about their food habits and behaviour.
family, collector’s name etc.
e. Key
b. Botanical gardens
- It is an analytical method of identification of organisms
- These are specialized gardens having collections of living based on similarities and dissimilarities.
plants for reference and identification. - It is based on the contrasting characters generally in a pair
- Each plant is labelled with its botanical name and family. called couplet.
- Famous botanical gardens: - Each couplet has two opposite options. Of these, only
o Royal Botanical Garden at Kew (England). relevant option is accepted and other is rejected.
o Indian Botanical Garden, Howrah (India).
- Each statement in the key is called a lead.
o At National Botanical Research Institute, Lucknow (India).
c. Biological Museum Flora, manuals, monographs & catalogues
- It is a collection of preserved plants and animals for study - Flora: Actual account of habitat and distribution of plant
and reference. species of a given area.
- A museum contains - Manuals: The record that contains information for
Specimens preserved in preservative solutions in identification of names of species found in an area.
containers or jars. - Monographs: The records that contain information on any
Preserved dry specimens of plants and animals. one taxon.
Insects preserved in insect boxes after collecting, killing - Catalogue: Alphabetical list of species.
and pinning.
2
