UNIT- 3
Q. What direct value does a forest have for man ?
Ans: Forests contribute to the economic development of our country by providing
goods and services to people and industry. They are intimately linked with our
culture and civilization. Forests are useful to humans for the following reasons:
1. Forests provide timber for the building and furniture.
2. Forests provide raw materials for the paper industry, board industry, plywood
industry etc.
3. Forests yields bamboos, which is called poor man’s timber. Industrially bamboos
are used as a raw material in paper and rayon industry.
4. Forests provide fuel energy needs to villagers staying in their vicinity. They also
provide fodder and grazing grounds for their animals.
5. Forests provide various minor forest products such as fruits, nuts, gums, resins,
tannins, rubber, lac, dyes, fibers, medicines, katha, insecticides, camphor,
essential oils, soap substances, cooking oils and spices.
6. Forests also provide various animal products such as musk, honey, was, tusser or
mooga silk etc.
Q. Why should we conserve forests and wildlife?
Ans. Forests and wildlife play a vital role in the life and culture of the people. They
form an important renewable natural resource and act as a source of gene pool for flora
and fauna used in breeding programs in agriculture and animal husbandry. Forests attract
rain fall bearing clouds act a sponges and to replenish the water table. Wild life resources
provide aesthetic, biological and nutritional value to human life on earth. When man
destroys forests and wild life, the ecological balance is upse.
Q. What is biodiversity?
Ans. Biodiversity, short for “biological diversity”, refers to the variety of life on Earth.
There are many levels of diversity from DNA and genes to species, populations,
ecosystems, and communities.
Genetic diversity refers to the variety of genes within individual plants and
animals and between different species. Think of the seedlings that grow from a packet of
new seeds or the variety of people within your own family. No two plants and no two
people are exactly alike.
Species diversity refers to the variety of different types of plants and animals,
including bacteria, fungi, insects, mammals, plants, and everything in between.
Differences occur within and between populations of species.
Ecosystem diversity refers to the variety of habitats and climates on Earth. The
interaction between these ecosystems and the species that live in them underpin all life on
Earth. In fact, Earth’s biodiversity helps keep our air and water clean, regulates our
climate, and provides us (and other plants and animals) with food, shelter, clothing,
medicine, and other useful products. What makes life on earth so complex is this
diversity and how it all interacts.
Q. What is a species ? What is an ecosystem?
Ans. A species is a group or population of similar organisms that reproduce among
themselves but do not naturally reproduce with any other kinds of organisms. Examples
of species include this splashback poison dart fron (right), monarch butterflies, red oak
trees, and humans.
According to the scientists of the Ecological Society of America, an ecosystem is
any geographic area, including the living organisms that live there and the nonliving parts
of the physical environment. Energy and matter move through and are stored in the
living and nonliving things and the interactions between them within the ecosystem.
Ecosystems are living places. Examples include tropical and temperate forests, deserts,
mountain tops, coral reefs, wetlands, and prairies.
Q. Why does biodiversity consist of several parts genetic diversity, spacies diversity,
and ecosystem diversity ?
Ans. Life on Earth takes a variety of forms, and all these parts are needed to keep the
Earth healthy. Genetic diversity ensures that parents pass on the traits (such as disease
resistance and physical features) that their offspring need to survive. When small
populations are isolated from other populations of their species, they may be forced to
inbreed, possibly leading to a loss of genetic diversity and to the extinction of the
population.
Species diversity ensures that ecosystems survive. For example, a giraffe cannot
do the same pollination job as a bee, nor could a bee play the same role in a savanna
ecosystem as a giraffe. There are some species that depend on a single species to survive.
Sloth moths live only on sloths. African melons depend solely on aardvarks. When a
species disappears, it can affect a whole ecosystem.
Ecosystem diversity ensures the health of the entire planet. For example,
rainforests acts as filters for the Earth’s air, absorbing carbon dioxide and releasing
oxygen. Oceans also absorb carbon dioxide, a well – known green house gas that causes
global warming. Wetlands and estuaries act as filters for the Earth’s freshwaters and
nurseries for the Earth’s marine populations. Without these ecosystems, life on Earth
would be very different than what it is today.
Q. What are the threats to biodiversity ?
Ans.

Habitat destruction, fragmentation, and degradation - agricultural conversion,
urbanization, wetland draining, forest fratmentation.

Water use – infrastructure changes, irrigation, municipal use.

Environmental contaminants and pollution.

Global climate change.

Over exploitation, over fishing, over hunging, poaching and non animal impacts
like over grazing and

Invasive species.