UNIT III b. Chemical components: Organic substances ( Proteins, lipid etc.

,) and
Inorganic substances (Macro components like C,H,O,N,P,K etc., and
ECOSYSTEMS AND BIODIVERSITY Micro components like Al, Co, Zn, Cu etc.,)

ECOSYSTEM II) Write the function of an ecosystem.

Ecosystem: A group of organisms interacting among themselves (or) with FUNCTIONS OF ECOSYSTEM:
environment.
The function of ecosystem is to allow the flow of energy and cycling of
Ecology: It is the study of ecosystem. (i.e.) The study of interaction among nutrient. These are of 3 types.
group of organisms with their environment
1. Primary function: Manufacture of starch (photosynthesis)
I) Explain the components of an ecosystem.
2. Secondary function: Distribution of energy in the form of food to all
consumers
COMPONENTS (OR) STRUCTURE OF ECOSYSTEM: 3. Tertiary function: Decomposition of dead systems and the initiation
of “cycling”
1. Biotic components:
a. Producers (autotrophs): They synthesis their food themselves by The function of the ecosystem can be understood well by the following terms.
photosynthesis. (e.g.) All green plants. Photosynthesis is a process in  Energy and nutrient flow
which CO2 & H2O is converted into glucose in the presence of sunlight  Food chain and food web
and chlorophyll.  Food pyramids

6CO2 + 12 H2O C6H12O6 + 6O2 + 6H2O

III) Discuss the energy flow in an ecosystem.
b. Consumers (heterotrophs): ENERGY FLOW:
 Primary consumers (or) Herbivores: These are plant eaters. E.g Energy flow: Solar energy (primary energy source of the earth) is transferred
to chemical energy by photosynthesis and is transferred to consumers by the
deer, rabbit etc.,
process of eating. The energy flow follows two laws of thermodynamics.
 Secondary consumers (or) primary carnivores: These are meat First law: Energy can neither be created nor destroyed, but can be converted
eaters. E.g frog, foxes etc., from one form to another form. E.g., solar energy is converted into chemical
 Tertiary consumers (or) secondary carnivores: These are also meat energy by photosynthesis.
eaters. E.g lion, tigers etc., Second law: Whenever energy is transferred, there is a loss of energy through
c. Decomposers: They decompose the dead bodies of plants & consumers & the release of heat. E.g., there will be a loss of energy (80 – 90%) in the form
of heat as it moves from one tropic level to another through respiration,
converts them into simpler compounds. E.g bacteria and fungi.
running, hunting etc.,
2. Abiotic components:
a. Physical Components: e.g air, water, soil, sunlight, energy, climate,
living space etc.,

1
 1. Grazing food chain: Starts with green plants. It starts with green
plants (producers) and it is grazed by herbivores which is further eaten
by carnivores.

IV) Explain food chain, food web with example. Mention its
significance.

FOOD CHAIN: It is the sequence of eating and being eaten in an ecosystem. 2. Detritus food chain: starts with dead organic matter.
It starts with plants and ends with animals.

E.g. Food chain in grass land

TROPIC LEVEL (OR) FEEDING LEVEL:

The various steps through which food energy passes in an ecosystem is called
tropic levels. These are arranged in the following way.
Food chain in pond

Where,
T1 represents producers, T2 represent primary consumers, T3 represents
Food chain in forest secondary consumers, T4 represents tertiary consumers and T5 represents
decomposers.

FOOD WEB: It is the interlocking pattern of various food chains in an

ecosystem. In food web, there is a no. of opportunities of eating and being
eaten at each tropic level.

There are two types of food chains

2
 Pyramid of numbers (Inverted)
This type of ecological pyramid is seen in parasitic food chain where
one primary producer supports numerous parasites which support more
hyperparasites.

Significance of food chain and food web:

1. Energy flow and nutrient cycling takes place through them.
2. Regulates the population size of different tropical levels.
3. They have the property of biomagnifications. The non-biodegradable
materials keep on passing from one tropic level to another. At
each successive tropic level, the concentration keeps on
increasing. This process is known as biomagnifications. 2. Pyramid of energy: It represents amount of energy present in each
tropic level.
V) What is ecological pyramid? Explain its types.

ECOLOGICAL PYRAMIDS: It is the graphical representation of structure and

function of ecosystem, starting with producers at the bottom and each
successive tropic levels forming the apex(upright). Sometimes the ecological
pyramid may be inverted. These are of 3 types of ecological pyramids.
1. Pyramid of numbers (upright): it represents the no. of organisms in
each tropic level.

(Note: Energy pyramids are never inverted. Because energy is

always lost from one tropic level to another tropic level.)
3. Pyramid of biomass: It represents the total amount of biomass present
in each tropic level.

3
 It gives overall picture of transfer of energy from one trophic level to the next.
Limitations of ecological pyramids :
• It assumes a simple food chain, something that almost never exist in
nature. It does not consider a food web.
• It does not take into account the same species belonging to two or more
trophic level.

VI) Explain the stages, types and process of ecological

succession.

ECOLOGICAL SUCCESSION:
It is the progressing replacement of one community by another till the
development of stable community. It includes two stages.
1. Pioneer community: The first group of organisms, which
establish their community in the area is called pioneer
As we move through a pyramid from the bottom to top the number, energy,
community.
biomass everything is decreasing from producer to consumers. 2. Seral or seres community: The various developmental stages of
Pyramid of biomass (Inverted): a community are called seral or seres.
In a pond ecosystem, the mass of phytoplankton (major producers) at any given
point will be lower than the mass of the heterotrophs, such as fish and insects. Types of ecological succession:
This is explained as the phytoplankton reproduce very quickly, but have much Ecologists recognize two types of ecological succession based on the
shorter individual lives. conditions present at the beginning of the process.
1. Primary succession: It involves the gradual establishment of
biotic communities on a lifeless ground.
(a) Hydrarch (or) Hydrosere: Establishment starts in a watery
area like pond and lake.
(b) Xerarch or Xerosere: Establishment starts in a dry area like
desert and rock.
2. Secondary succession: It involves the establishment of biotic
communities in an area, where some type of biotic community is
already present.
Process of ecological succession:
1. Nudation – This is the first step in succession. Development of bare
area (without any life) formation may occur due to volcanic eruption,
dry climate, forest destruction, storm etc.
2. Invasion: It is the establishment of one or more species through
migration followed by establishment.
Importance of ecological pyramid:
• Easy to understand.
4
 a)Migration: Migration of seeds is brought about by wind, water or Tropical deciduous They are found little away from the equator.
birds. forests. They are characterized by a warm climate and
b)Establishment: The seeds then germinate and grow on the land and rain is only during monsoon. They have
establish their pioneer communities. different types of deciduous trees like maple,
3. Competition: As the number of individual species grows, there is a
oak and hickory and animals like deer, fox,
competition with the same species and between different species for
space, water and nutrients etc., rabbit and rat.
4. Reaction: The living organism takes water, nutrients, grow and
modify the environment. This is known as reaction. This modification Tropical scrub forests These are characterized by a dry climate for
becomes unsuitable for the existing species and favours some new linger time. They have small deciduous trees
species, which replace the existing species. This leads to seral and shrubs and animals like deer, fox, etc.,
communities.
5. Stabilization: It leads to a stable community, which is in Temperate rain forests They are found in temperature areas with
equilibrium with the environment. This community is called as climax adequate rainfall. They are characterized by
community. coniferous trees like pines, firs, red wood etc.,
and animals like squirrels, fox , cats, bear etc.,
TYPES OF ECOSYSTEM
Temperate deciduous They are found in areas with moderate
VII) Describe the types, characteristic features, structure and forests temperatures. They have major trees including
function of forest ecosystem. broad leaf deciduous trees like oak, hickory
and animals like deer, fox, bear, etc.,
FOREST ECOSYSTEM:
The forest occupies nearly 40% of the world’s land area. In India it occupies
only 19% of its total land area. Characteristics of forest ecosystems:
• Forests are characterized by warm temperature and adequate rainfall,
Types of forest ecosystem: which make the generation of number of ponds, lakes etc.,
• Tropical rain forests. • The forest maintains climate and rainfall.
• Tropical deciduous forests. • The forest support many wild animals and protect biodiversity.
• Tropical scrub forests. • The soil is rich in organic matter and nutrients, which support the
• Temperate rain forests. growth of trees.
• Temperate deciduous forests. • Since penetration of light is so poor, the conversion of organic
matter in to nutrients is very fast.
Features of different types of forests:
Name of the forest Features Structure (Components) and function of Forest ecosystem:
Tropical rain forest They are found near the equator. They are
characterized by high temperature. They have
broad leaf trees like teak and sandal and the
animals like lion, tiger and monkey.

5
 2. Temperate grasslands
3. Polar grasslands.
Features of different types of Grassland:
Name Features
Tropical They are found near the borders of tropical rain
grasslands. forests. They are characterized by high
temperature and moderate rainfall (40 to 100 cm).
It is also known as Savanna-type. They have tall
grasses with scattered shrubs and stunted trees and
animals like zebras, giraffes, antelopes, etc
Temperate They are usually found in the centers of continents,
Food chain of Forest ecosystem:
grasslands on flat, sloped hills. They are characterized by very
cold winters and hot summers. Intense grazing and
summer fires, do not allow shrubs or trees to grow.
Polar grasslands. They are found in arctic Polar Regions. They are
characterized by severe cold and strong winds
along with ice and snow. In summers several small
annual plants grow. They have animals like arctic
Food web of Forest ecosystem: wolf, weasel, arctic fox etc.,
Characteristics of Grassland Ecosystems:
• Grassland ecosystem is a plain land occupied by grasses.
• Soil is very rich in nutrients and organic matter.
• Since it has tall grass, it is ideal place for grazing animals.
• It is characterized by low or uneven rainfall.
Structure (Components) and function of Grassland ecosystem:

VIII) Describe the types, characteristic features, structure and

function of Grassland ecosystem.

GRASSLAND ECOSYSTEM:
Grassland occupies about 20% of earth’s surface.
Food chain of Grassland ecosystem:
Types of grassland ecosystem :
1. Tropical grasslands.

6
 Temperate deserts. They are found in South California (Majave). They
are characterized by very hot summer and very
cool winter time.
Cold deserts. They are found in China (Gobi desert). They are
characterized by cold winters and warm summers.
Characteristic features of Desert ecosystems:
• The desert air is dry and the climate is hot.
• Annual rainfall is less than 25 cm.
Food web of Grassland ecosystem: • The soil is very poor in nutrients and organic matter.
• Vegetation is poor.
Structure (Components) and function of Desert ecosystem:

IX) Describe the types, characteristic features, structure and Food chain of Desert ecosystem:
function of Desert ecosystem.

DESERT ECOSYSTEMS:
Desert occupies about 35% of our worlds land area. It is characterized by less
than 25cm rainfall.
Types of desert ecosystems:
1. Tropical deserts.
2. Temperate deserts. Foodweb of Desert ecosystem:
3. Cold deserts.
Features of different types of Grassland:
Name Features
Tropical deserts. Tropical deserts are found in (i) Africa (Sahara
desert) (ii) Rajasthan (Thar Desert). They are
characterized by only few species. Windblown
sand dunes are very common.

7
 • Lake is a shallow fresh water body.
X) Describe the types, zones, characteristic features, structure • It is a permanent water body with large water resources.
and function of Lake Ecosystem. • It helps in irrigation and drinking.
Structure (Components) and function of Lake ecosystem:
LAKE ECOSYSTEM:
Types of lakes:
• Oligotropic lakes: They have low nutrient concentrations.
• Eutrophic lakes: They are over nourished by nutrients like N and
P.
• Dystrophic lakes: They have low pH, high humic acid content and
brown waters.
• Volcanic lakes: They receive water from magma after volcanic
eruptions.
• Meromictic lakes: They are rich in salts. Food chain of Lake ecosystem:
• Artificial lakes: They are created due to construction of dams.

Zones of Lake:

Depending upon their depth and distance from the shore, lakes consists of four
distinct zones.
• Littoral zones: It is the top layer of the lake. Food web of Lake ecosystem:
• Limnetic zone: Next to the littoral zone is limnetic zone, where
effective penetration of solar ligt takes place.
• Profundal zone: The deep open water, where it is too dark.
• Benthic zone: This zone is found at the bottom of the lake

XI) Describe the zones, characteristic features, structure and

function of ocean ecosystem.

SALT WATER ECOSYSTEM - OCEAN(MARINE) ECOSYSTEMS:

• Oceans cover more than two thirds of the earth’s surface.
Characteristic feature of Lake Ecosystem:
8
 • The ocean environment is characterized by its high concentration of
salts and minerals.
• It supplies huge variety of sea-products and drugs.
• It also provides us iron magnesium, phosphorous and natural gas.
Zones of Oceans:
• Euphotic zone: It receives abundant light and shows high
photosynthetic activity.
• Bathyal zone: It receives dim light and is usually geologically active. Food web of ocean ecosystem:
• Abyssal zone: It is the dark zone and is very deep (2000 to 5000
metres).

Characteristic features of Ocean Ecosystems: BIO DIVERSITY

• It occupies a large surface area with saline water.
• Since ship, submarines can sail in ocean, commercial activities may Biodiversity is defined as “The variety and variability among all
be carried out.
groups of living organisms and the ecosystems”.
• It is rich in biodiversity.
• It moderates the temperature of the earth.
I) Mention the classification of biodiversity.
Structure (Components) and function of Ocean ecosystem:
CLASSIFICATION OF BIODIVERSITY:
 Genetic diversity: It is the diversity within the species. (e.g) Rice
varieties.
 Species diversity: It is the diversity between different species. (e.g)
Plant and animal species.
 Community ecosystem diversity: It is the diversity at the ecological
level. (e.g) River system.

II) What are the values of biodiversity? Explain.

Values of Biodiversity:
Food chain of ocean ecosystem:
Biosphere is a life supporting system to human beings. Each organism
in the biosphere has its own significance. Biodiversity is must for the stability

9
& proper functioning of the biosphere. The values have been classified as 6. Optional values: This suggests that any species may be proved to be a
follows. valuable species. (e.g.,) The growing biotechnology field searching a
species for curing the diseases of cancer & AIDS.
1. Consumptive use values: These are direct use values of Nature’s
products. (ie) here the biodiversity products are harvested and III) Why india is called a mega diversity nation.
consumed directly.
Ex. food, drug, fuel etc., Mega-diversity Regions:
(a) Food: A large number of wild plants are consumed by human
beings as food. Nearly 80-90% of our food crops have been These are nearly 170 countries in the world and 12 of them contain
70% of our global biodiversity. Those 12 countries Australia, Brazil, China,
domesticated only from the tropical wild plants. A large number of
Colombia, Ecuador, U.S, India, Indonesia, Madagascar, Mexico, Peru, and
wild animals are also consumed as food. Congo are known as mega diversity regions.
(b) Drugs: Around 70% of modern medicines are derived from plant
and plant extracts. 20,000 plant species are believed to be used India – As a mega diversity nation:
medicinally particularly in the traditional systems of Unani, Ayurveda
and Siddha. India is second largest nation containing 5% of world’s biodiversity.
(c) Fuel: Firewood are directly consumed by villagers, tribes. The India gets, 10th rank in the plant rich countries, 11th rank in the endemic
species, and 6th rank in the origin of agricultural crops.
fossil fuels like coal, petroleum and natural gas are also the products of
fossilized biodiversity. No. of plants & animal species in India:
2. Productive use values: Here the biodiversity products may be derived
from the animals and plants. (e.g.,) Silk from silk-worm, wool from Animal species - 89,450(7.31% of global faunal
sheep, musk from elephant, leather from all animals etc., species)
3. Social values: These values are associated with the social life, religion Plant species - 47,000 (10.9% of global floral
species)
and spiritual aspects of the people. (e.g.,) Holy plants & Holy animals
Flowering plants - 20,000
4. Ethical values: It involves ethical issues like “All life must be Medicinal plants - 3,000
preserved”. These have great values on religious & cultural basis. Our Insects - 67,000
rich heritage teaches us to worship plants, animals, rivers and Fishes - 1,460
mountains. The ethical value means that a species may or may not be Birds - 1,200
used, but its existence in nature gives us pleasure. (e.g.,) We are not Reptiles - 420
deriving anything directly from Kangaroo, Zebra or Giraffe but we feel Mammals - 340
Domesticated plants and animals – 170 etc.,
that these should exist in nature. Thus, there is an ethical value
attached to each species.  Indian Sandal wood has high commercial value
5. Aesthetic value: The beautiful nature of plants and animals insists us  Indian tobacco has high nicotine content
to protect the biodiversity. The most important aesthetic value of  Several species of edible mushrooms are cultivated and exported to
biodiversity is ecotourism. advanced countries.

10
  About 100 species of micro organisms were collected from Indian soil 3. Climate Change: It is brought about by the accumulation of green
and cultured in the foreign laboratories. house gases. Some organisms cannot accommodate the changes.

IV) Define the following terms. V) Explain the threats and conservation of biodiversity.

Definition of Some Important terms: THREATS TO BIODIVERSITY:

Any disturbance in a natural ecosystem tends to reduce its
1. Endemic species: The species which are found only in a particular biodiversity, and threatens the normal ecological cycle.
region. Ex. Giant panda, Red kangaroo There are 3 important threats to biodiversity.
2. Extinct species: When the species are no longer found in the world.
Ex. Dodo, Passenger pigeon 1. Habitat Loss
3. Endangered (or) Threatened species: When its no. has been reduced
to a critical level. These species are in immediate danger of extinction.
2. Poaching (Over harvesting) of wildlife
Ex. Tiger, Peacock 3. Man – wildlife conflicts.
4. Vulnerable species: when its population is facing continuous decline
due to over exploitation. Such a species is still abundant. Ex. Blue 1. HABITAT LOSS: The loss of population by habitat loss is due to
sheep, Asiatic elephant, Gangetic dolphin.
5. Rare species: A species is said o be rare, when it is localized (a) Deforestation: The loss of habitat is mainly caused by
within restricted area. They are thinly scattered over a more deforestation activities. Forests and grasslands have been cleared for
conversion into agricultural lands, or settlement areas or
extensive area. Such species are not endangered or vulnerable.
developmental project. The forest and grasslands are the natural
Ex. Orangutan, Pink slug (Australia) homes of thousands of species, which disintegrate due to loss of their
6. Red date book: It contains the list of endangered species of plants & natural habitat.
animals. (i.e) The red date book gives the warning signal to the (b) Destruction of wetlands: The wetlands, estuaries and
endangered species. If not protected they become extinct in the near mangroves are destroyed due to draining, filling and pollution which
future. cause huge biodiversity loss.
7. Hot spots: These are the geographic areas which posses the high (c) Habitat fragmentation: Sometimes the habitat is divided into
endemic species. These are the areas of high conservation priority. small and scattered patches. This phenomenon is known as habitat
Myers etal., recognized 25 hot spots in the world, 2 of which are found fragmentation. Due to this many wild animals and songbirds are
in India. They are 1. Eastern Himalayas 2. Western Ghats. vanishing.
(d) Raw material: For the production of hybrid seeds, the wild
plants are used as raw materials. As a result, many plant species
Factors affecting Endangered & Endemic species: become extinct.
1. Pollution: Humans disposed their waste products on nature. These (e) Production of drugs: Many pharmaceutical companies collect
pollutants accumulates in the tissue of living things through food chain, wild plant for the production of drugs. Therefore several medicinal
finally it leads to the death. plant species are on the verge of extinction.
2. Over Exploitation: Over exploitation of natural resources & poaching (f) Illegal trade: Illegal trade on wild life also reduces the bio-
of wild animals.
diversity and leads to habitat loss.
11
 (g) Developmental activities: Construction of massive dams in the CONSERVATION OF BIODIVERSITY:
forest areas, discharge industrial effluents which kill the birds and Biodiversity is one of the important tool for sustainable development.
other aquatic organisms. The enormous value of biodiversity due to their commercial, social, ethical,
aesthetical and ecological importance emphasizes the need to conserve
2. POACHING OF WILD LIFE: Poaching means killing of animals. It biodiversity.
leads to loss of animal biodiversity.
There are 2 types of poaching. TYPES (OR) STRATEGY OF BIODIVERSITY CONSERVATION:
 Subsistence poaching: It involves killing of animals to provide
enough food 1. In-situ conservation (within habitat)
2. Ex-situ conservation (outside habitat)
 Commercial poaching: It involves killing of animals to sell their
products.
IN- SITU CONSERVATION:
Factors influencing poaching:
It involves protection of fauna and flora within its natural habitat. The
 Human population: It led to pressure on forest resources that ultimately natural habitats under In situ conservation are called “Protected areas”.
cause degradation of wild life. Methods: Around 4 % of the total geographical area of the country is used for
 Commercial activities: The trading of wildlife products is highly profit. the in-situ conservation. The following methods are presently used for in-situ
Therefore, the poachers hunt wildlife and smuggle it to other countries. conservation.
Ex: (i) Elephant: It is killed for ivory. (ii). Bengal tigers: Its fur 1. Biosphere reserves
sell is more than $1,00,000 in the foreign market. 2. National parks
3. Wild-life sanctuaries etc.,
Remedial measures: 4. Other projects
 Illegal hunting and trade of animals should be stopped.
 Biodiversity laws should be strengthened. 1. Biosphere reserves:
 It covers more than 5000 sq kms of area.
3. MAN- WILDLIFE CONFLICTS: It arise, when wildlife cause immense  It gives long term survival of ecosystem.
damage to human beings. Under such conditions, it is difficult to  It protects endangered species.
compromise the affected villagers and to gain their supports for wildlife  It serves as site of recreation & tourism.
conservation.  It is useful for educational & research purpose.
Factors influencing man-wildlife conflicts: Restriction: No explosive activities are permitted.
 Shrinking of forest cover Ex. 1. Nanda Devi (UP) 2. Sunderbans (West Bangal) 3. Gulf of Mannar
 Human encroachment into the forest area (TN)
 Injured animals have a tendency to attack man
 Movement of animals out of forest for searching of food 2. National Park:
 Cash compensation for the affected farmers is not enough.  It covers about 100 – 500 sq. kms of area.
Remedial measures:  Within the biosphere reserve one or more national parks are also
 Adequate crop & cattle compensation scheme must be started exists.
 Cropping pattern near the forest area should be changed  It serves as a site of recreation and tourism
 Adequate food and water should be made available within the forest zone.  It is used to protect and develop the wildlife.
 Developmental activities in and around forest area must be stopped. Some important national parks in India.

12
 Name of National park State wildlife involves the preservation of seeds, pollen of some important crops by
Kaziranga Assam One horned Rhino using liquid N2 at a temp -196oC for several years.
Gir National Park Gujarat Indian Lion 2. NBAGR: National Bureau of Animal Genetic Resources: It is located at
Karnal, Haryana. It preserves the semen of domesticated bovine animals.
3. Wildlife sanctuaries: 3. NFPTCR: National Facility for Plant Tissue Culture Repository: It is
used for the conservation of varieties of crop plants by tissue culture.
 It is an area which is reserved for the animals only.
 It allows the operations such as harvesting of timber, collection of
Advantages:
forest products, private ownership rights etc.,
 Special care & attention of species
Restriction: Killing, hunting, shooting of wildlife is prohibited.
 Animals are assured food, water, shelter & security & hence longer
Some important Wild life Sanctuaries in India.
life span.
 It is carried out for endangered species.
Name of Sanctuary State Wildlife 
Vedanthangal Bird Sanctuary Tamilnadu Water birds Disadvantages:
Mudumalai wildlife sanctuary Tamilnadu Tiger, Elephant  Expensive method
 Freedom of wildlife is lost
4. Other projects: Some special projects are framed in our country for the  Animals cannot survive in natural environment
protection & conservation of certain animals. Example. Project lion,
Project elephant, Gir lion project etc.,
PART-A QUESTION & ANSWERS
Advantages:
 Very cheap and convenient method 1. What is meant by biome ?
 Species gets adjusted too the natural disasters. A group of ecosystems that have the same climate and similar
dominant communities. The biosphere can be broken in to biomes.
Disadvantages:
2. What are tropic level or feeding levels?
 Large surface area is required
 Maintenance is not proper due to lack of staff members & pollution
The various steps through which food energy passes in an
EX-SITU CONSERVATION: ecosystem is called tropic levels. These are arranged in the
following way
It involves the protection of fauna & flora outside the natural habitats.
It is done mainly for the conservation of crop varieties. Some of the important
exsitu conservation practices are botanical gardens, seed banks, microbial
culture collections, tissue & cell cultures, zoological gardens etc.,

Methods: Where,
T1 represents producers, T2 represent primary consumers, T3
1. NBPGR: National Bureau of Plant Genetic Resources: It is located in
New Delhi. It uses cryo preservation technique to preserve crops. It represents secondary consumers, T4 represents tertiary
consumers and T5 represents decomposers
13
3. What is hydrological cycles? of th world floral species. The loss of biodiversity or endemim is
Movement of water in a cyclic manner is known as hydrological about 33%.
cycle. 11. Write a note on RED data Book. (Refer Notes)
4. What are nutrient cycles? 12. What would happen to an ecosystem if all the producers
The cycle flow of nutrients between the biotic and abiotic were eliminated?
components is known as nutrient cycle or biogeochemical The removal of the producers would cause the collapse of the
cycle entire food web. Primary consumers or herbivores, which feed
5. What is ecological succession? (Refer Notes) on producers directly, would die off. ... Higher level consumers
6. What is meant by keystone species? would suffer as organisms from lower trophic levels start to die
Species which are described as playing a critical role in maintaining off.
the structure of an ecosystem. Elimination of a keystone species
dramatically alters the structure and function of a community. Ex. 13. Write the various adaptive features of desert plants.
Sharks, parrot fish. Water conservation is vital to surviving in the desert. So the
7. What is meant by indicator species. plants in desert conserve water by minimizing water loss
A species whose status provides information on the overall condition
through the surface of their leaves. Many have the ability to
of the ecosystem and of other species in that ecosystem. They reflect
close leaf pores, called stomata, through which gas and water
the quality and changes in environmental conditions as well as
aspects of community composition.
are exchanged, during drought conditions.
Ex. Pollinators such as honeybees and butterflies both indicate and
strongly influence the health of plant populations 14. What is meant by invasive species?

8. What is biodiversity? An invasive species is a species that is not native to a specific

Biodiversity is defined as “The variety and variability among all location, and that has a tendency to spread to a degree believed to
groups of living organisms and the ecosystems in which they cause damage to the environment, human economy or human
occur.” health. Ex. European rabbit in Australia
9. Define hot spots of bio diversity.
The hot spots are the geographic areas which possess the high
endemic species. In India there are 2 hotspots. 1. Eastern Himalayas
2. Western Ghats
10. India is a mega diversity nation. Account.
India is one among the 12 mega-diversity countries in the world.
It has 89,450 animal species accounting for 7.31% of the global
faunal species and 47000 plant species which accounts for 10.8%

14