India is one of the recognized megadiverse countries of the world.
In terms of species richness –
- o 7th rank in mammals
o 9th rank in ninth bird
o 5th rank in reptiles.
In terms of endemism of vertebrate groups, India’s position is 10th in birds with 69
species, 5th in reptiles with 156 species and 7th in amphibians with 110 species.
India’s geographical area under forest and tree cover – 24.16% (Indian forest report
2015). Of the 34 globally identified biodiversity hotspots, India harbors two hotspots,
i.e., Eastern Himalayas, Western Ghats, and Sri Lanka.
India represents –
a) 2 realms
b) 5 Biomes
c) 10 Bio-geographic zones
d) 25 Bio-geographic provinces
Biogeographic realms are large spatial regions within which ecosystems share a broadly similar biological evolutionary history.
Realm is a continent or sub-continent sized area with unifying features of geography
and fauna & flora.
In the world – 8 biogeographic realms are there –
- o Nearctic realm
o Palaearctic realm
o Afrotropical realm
o Indomalayan realm
o Oceania realm
o Australian realm
o Antarctic realm
o Neotropical realm
In India – 2 realms are there –
- The Himalayan region represented by Palearctic Realm
- Rest of the sub-continent represented by Malayan Realm.
Biomes of India
Biosphere, which is one of the level of organizations in ecology, has many divisions and
each division is known asBiome.
Each biome has a different climate, vegetation, animals and soil type. No two biomes are the same.
Climate, vegetation, animals decide the boundaries of biomes.
Most important climatic factors are – temperature and precipitation.
5 biomes of India are –
1. Tropical Humid Forests
2. Tropical Dry or Deciduous Forests (including Monsoon Forests)
3. Warm deserts and semi-deserts
4. Coniferous forests and
5. Alpine Meadows
Biogeography deals with the geographical distribution of plants and animals.
Biogeography is divided into branches –
1. Phyto-geography (plant geography) – It deals with origin, distribution and
environmental interrelationships of plants.
2. Zoogeography – It deals with the migration and distribution of animals.
There are 10 biogeographic zones which are distinguished clearly in India. They are as follows –
- Extension of the Tibetan plateau.
- High-altitude cold desert in Laddakh (J&K) and Lahaul Spiti (H.P).
- Mountain chain running from north-western to northeastern India.
- It comprises a diverse range of biotic provinces and biomes.
- The extremely arid area west of the Aravalli hill range.
- Comprises both the salty desert of Gujarat and the sand desert of Rajasthan.
4. Semi-arid –
- The zone between the desert and the Deccan plateau, including the Aravalli hill
5. Western Ghats
- Hill ranges and plains running along the western coastline, south of the Tapti river.
- Covers an extremely diverse range of biotic provinces and biomes.
6. Deccan peninsula
- Largest of the zones
- Covers much of the southern and southcentral plateau with predominantly deciduous vegetation.
7. Gangetic plain
- Defined by the Ganges river system, these plains are relatively homogenous.
8. North-east India
- The plains and non-Himalayan hill ranges of northeastern India.
- The wide variety of vegetation.
- The Andaman and Nicobar Islands in the Bay of Bengal.
- A highly diverse set of biomes.
- A large coastline distributed both to the west and east, with distinct differences between the two.
It is an eco-systematic or biotic subdivision of realms.
India is divided into 25 biogeographic zones.
Biogeographic zones and Biogeographic Provinces of India.
|S.No.||Biographic zones (10)||Biogeographic provinces (25)|
|1||Trans Himalaya||1A: Himalaya – Ladakh Mountains|
1B: Himalaya – Tibetan Plateau
1C: Trans – Himalaya Sikkim
|2||The Himalaya||2A: Himalaya – North West Himalaya|
2B: Himalaya – West Himalaya
2C: Himalaya – Central Himalaya
2D: Himalaya – East Himalaya
|3||The Indian desert||3A: Desert – Thar|
3B: Desert – Katchchh
|4||The Semi-Arid||4A: Semi – Arid – Punjab Plains|
4B: Semi – Arid – Gujarat Rajputana
|5||The Western Ghats||5A: Western Ghats – Malabar Plains|
5B: Western Ghats – Western Ghats Mountains
|6||The Deccan peninsula||6A: Deccan Peninsular – Central Highlands|
6B: Deccan Peninsular – Chotta Nagpur
6C: Deccan Peninsular – Eastern Highlands
6D: Deccan Peninsular – Central Plateau
6E: Deccan Peninsular – Deccan South
|7||The Gangetic Plains||7A: Gangetic Plain – Upper Gangetic Plains|
7B: Gangetic Plain – Lower Gangetic Plains
|8||The Coasts||8A: Coasts – West Coast|
8B: Coasts – East Coast
8C: Coasts – Lakshadweep
|9||Northeast India||9A: North – East – Brahmaputra Valley|
9B: North – East – North East Hills
|10||Islands||10A: Islands – Andaman|
10B: Islands – Nicobars
Animals with backbones and spinal columns.
Most advanced organisms on Earth.
Represents only a very small percentage of all animals but their size and mobility often allow them to dominate their environment.
Live in water
Breathe underwater using gills, not lungs
Have scales and fins
Lay many eggs
Live on land & water
Breathe with lungs and gills
Moist smooth skin
Four legs (sometimes none)
Lay many eggs
Have dry skin
Usually, lay eggs
Ear holes instead of ears
4 legs or no legs
Have feathers and wings
Ear holes instead of ears
Have hair or fur
Give birth to live young
Mammal mother nurse their young one with milk
Breathe with lungs
Mammals live on land have 4 legs (or 2 legs & 2 arms), and ears that stick out.
They do not have backbones.
98% of animal species in the world are invertebrates.
They don’t have an internal skeleton made of bone. Many invertebrates have a fluid-filled, hydrostatic skeleton, like the jellyfish or worm. Others have a hard outer shell, like insects and crustaceans.
Their bodies are divided into segments.
Very well-developed internal organs.
Found almost anywhere in the world.
Don’t have any limbs.
Example – earthworms, leeches, roundworms, etc.
Most of them have soft, skin-like organ covered with a hard outside shell.
Some mollusks live on land like snail and slug.
Other mollusks live in water like oyster, mussel, clam, squid, and octopus.
They are marine animals which live in the ocean.
Example – a sea star, sea urchin, sand dollar and sea cucumber.
Most of them have arms or spines that radiate from the center of their body.
Simple, single-celled animals.
Smallest among all animals.
Most protozoa are microscopic.
They do breathe, move and reproduce like multicelled animals.
Example – amoebas, Flagellates etc.
They have limbs with joints that allow them to move.
They also have an exoskeleton, which is a hard, external skeleton.
They include crustaceans, insects, and arachnids.
They live mostly in the ocean or other waters.
They have a hard, external shell which protects their body
Example – crab, lobster, and barnacle.
They are class of invertebrates within the arthropod phylum.
They have a chitinous exoskeleton, a three-part body, three pairs of jointed legs,
compound eyes and one pair of antennae.
They are very adaptable, living almost everywhere in the world.
They have an exoskeleton that covers their entire body.
Example – fly, beetle, butterfly, moth, dragonfly, bee, wasp and praying mantis.
They are a class of joint-legged invertebrate animals (arthropods).
Example – spiders, scorpions, ticks, and mites.
They do not have antennae.
They have 2 body parts and 4 pairs of legs.
India ranks 10th in the world and 4th in Asia in terms of plant diversity. India represents nearly 11 % of the world’s known floral diversity.
Important groups found in India
The green non-differentiated plants (non – differentiated into organs like root, stem and
leaf) possessing chlorophyll are known as Algae.
They grow in water or in moist situations.
Fresh-water algae – green or blue-green in color
Marine water algae – red or brown.
These are autotrophic plants, as they can manufacture their own food.
Non-green non-differentiated plants characterized by total absence of chlorophyll are called Fungi.
They grow either on dead, rotten organic matters as saprophytes (a plant, fungus, or
microorganism that lives on dead or decaying organic matter) or live as parasites on
other living bodies, which are referred to as hosts.
Moulds and mushrooms are the familiar examples of saprophytic fungi.
The maximum diversity of fungi is in the Western Ghats followed by the eastern
Himalaya and the western Himalaya. About 3500 species are endemic to the country.
It is neither plant nor animal.
These are non-chlorophyllous micro-organisms which lead saprophytic or parasitic
If bacteria form a parasitic association with other organisms, they are classed as
pathogens. Pathogenic bacteria are a major cause of human death and disease and
cause infections such astetanus, typhoid fever, diphtheria, syphilis, cholera,
foodborne illness, leprosy and tuberculosis.
Saprophytic bacteria are rather beneficial. They are soil borne and many of them are
used in industries.
Other uses of bacteria include sewage treatment, breakdown of oil spills, cheese
They were among the first life forms to appear on Earth, and are present in most of its
Bacteria inhabit soil, water, acidic hot springs, radioactive waste, and the deep
portions of Earth’s crust.
A lichen is a peculiar combination of an algae and a fungus – the two live deriving mutual
benefit. (Lichen = algae + fungi)
They are group of greyish green plants which grow on rocks, three-trunks, dead wood,
Algae manufactures carbohydrate food which becomes available to the fungus, and the
latter absorbs and retains water and thus keeps the algal cells moist. So it is a nice
example of symbiosis. (algae makes food and fungi eats food))
In wetlands – found commonly
In rivers and streams – rare
In ground water – Not found
The plant body is differentiated into a small stem and simple leaves, but true roots are
They usually grow in moist places. E.g. Liverworts, mosses
2nd largest group of green plants in India distributed largely in Eastern Himalaya, Northeastern India, Western Himalaya and the Western Ghats.
Mosses constitute the major component of Indian bryoflora followed by liverworts and
The pteridophytes have well-differentiated plant bodies, consisting of roots, stems and
They possess vascular bundles (a strand of conducting vessels in the stem or leaves of a
plant, typically with phloem on the outside and xylem on the inside).
Most of them are terrestrial plants and some of them are aquatic.
This group includes the vascular cryptogams · like dub-mosses, horse-tails and fems
which are universally distributed all over the world.
The north-eastern region (including Eastern Himalaya) is rich in pteridophytic diversity,
followed by south India (including Eastern and Western Ghats) and north India (including Western Himalaya).
Gymnosperms (gymnos=naked, sperma=seed) are the naked-seeded plants.
Their naked condition stands in contrast to the seeds and ovules of flowering plants
(angiosperms), which are enclosed within an ovary.
They have very simple flowers without accessory whorls and the microsporophylls
(stamens) and carpels remain aggregated in cones.
Ovules are present on the surface of the carpels and are directly pollinated by the pollen
There is nothing like ovary, style and stigma, and naturally there is no fruit.
E.g. Cycas, Pinus, Gnetum.
The species of Gnetum and Cycas are mostly confined to North Eastern region, Eastern
and Western Ghats, and Andaman & Nicobar Islands.
Gymnosperms have major economic uses. Pine, fir, spruce, and cedar are all examples
of conifers that are used for lumber. Some other common uses for gymnosperms are
soap, varnish, nail polish, food, gum, and perfumes.
The flowering plants (angiosperms), also known as Angiospermae or Magnoliophyta,
are the most diverse group of land plants. Angiosperms (angeion=a case) are the closed
Like gymnosperms, angiosperms are seed-producing plants. They are distinguished
from gymnosperms by characteristics including flowers, endosperm within the seeds,
and the production of fruits that contain the seeds.
Angiosperms are the most highly developed plants which bear flowers having
conspicuous accessory and essential whorls.
- Carpels have the ovary, style and stigma.
With the stimulus of fertilization, the ovary usually develops into the fruit and the ovules into seeds. Thus the seeds remain within the fruits.