Biological Diversity – Maharashtra Board Class 8 Solutions for General Science

Biological Diversity – Maharashtra Board Class 8 Solutions for General Science (English Medium)

MathematicsGeneral ScienceMaharashtra Board Solutions

Solution 1.a

The variety of living things which exist on the Earth is called biological diversity or biodiversity.

Solution 1.b

Importance of biodiversity:

1. Biodiversity is essential for the existence of living things.
2. The needs of all living things including human beings are met because of the vast biodiversity.
3. The basic needs of man such as food, clothing, medicines and shelter are satisfied only because of biodiversity.
4. Balance between producers, herbivores, carnivores and decomposers can be maintained in nature because of biodiversity.
5. The survival of food chains is completely dependent on biodiversity.

Solution 1.c

Living things differ in the following respects:

1. Shape and size: Living things can be as small as microorganisms, unicellular plants and animals and as giant-sized as tall trees, elephants and whales.
2. Body structure and life processes: Living things vary with respect to body structure, organ systems, organs and life processes.
3. Eating habits: Variation is observed in different living organisms with respect to their eating habits.
4. Habitat and environment: Living organisms have varying habitats.
5. Genetic variation: The factors which transmit chromosomes from one generation to the next generation also show variations.

Solution 1.d

Reasons for the reduction of biodiversity are

1. Explosive growth of population
2. Single crop method of farming
3. Introduction of hybrid and imported breeds of animals
4. Hunting of animals
5. Deforestation for housing and industrial development
6. Construction of factories, dams, roads and mining
7. Environmental pollution, increase in temperature of the Earth and climatic changes

Solution 1.e

Efforts made to protect endangered species:

1. Passing laws for the protection of rare and endangered species
2. Creating national parks and wildlife sanctuaries
3. Declaring some areas as Reserved Biodiversity Zones
4. Undertaking special projects to nurture specific species
5. Nurturing some species of animals and plants in zoos and botanical gardens, respectively
6. Compiling and documenting traditional knowledge
7. Obtaining public participation in protecting and nurturing biodiversity
8. Establishing seed banks and gene banks for the conservation of genes of local varieties of living organisms
9. Hybridising local species with new species for the preservation of important characters

Solution 2.a

Herbivores feed on plants only. If all the herbivores in a forest get killed, then all the carnivores which feed on these herbivores will die because of starvation. It means that the predators will not be able to survive in the absence of their prey. If all the carnivores are killed, then the population of herbivores will increase. This will destroy all the vegetation, which in turn will disturb the ecosystem. Therefore, it is very important to preserve the prey-predator chains to maintain environmental balance and biodiversity.

Solution 2.b

The single crop method can prove harmful because of the following reasons:

1. It depletes the nutrients of the soil.
2. Some single crops may require more water and fertilisers than the other types of crops.
3. The insects or pests specific for a single crop may wipe out the total yield which results in huge losses to farmers.
4. In the single crop method of farming, farmers grow only those crops which yield bigger harvests and can be sold for high prices.
5. The traditional method of multi-crop farming may disappear because of the practice of single crop farming.
6. This endangers biodiversity and can prove harmful to the plant kingdom.

Solution 3.a

Importance of the environment:

1. The environment is an important factor which brings about biological diversity.
2. It provides living organisms with all their necessities.
3. All living and non-living components of the environment exist together and are dependent on each other.
4. Variation is observed even within the living organisms which live in the same environment because in any geographical region, the environment changes from place to place and in the course of time.
5. It is very important to preserve the prey-predator chain in an environment.
6. In any environment, if the balance between the number of producers and the number of herbivores, carnivores and decomposers is maintained, then only can nature’s food chain continue to survive.

Solution 3.b

Biotechnology:  

1. Local species of crops show several characteristics such as resistance to diseases, survival in adverse conditions, shorter life cycles etc. These species can be crossed with new species to get the advantage of these characteristics.
2. Biotechnology is used to bring about such changes in the hereditary characteristics of organisms.
3. Biotechnology is the manipulation of living systems to meet the needs of human beings.
4. It is necessary to carefully preserve the strains of local varieties. Seed banks have now been started for this purpose.
5. Gene banks for preserving the genes of local varieties have also become possible because of advances in biotechnology.
6. Biotechnology is used in many processes in daily life such as making of curd, cheese and different fermentation processes.
7. Modern biotechnology aims at advanced methods of agriculture such as tissue culture.

Solution 3.c

Reserved Biodiversity Zones:

1. Reserved Biodiversity Zones are the areas maintained for the conservation of biodiversity.
2. In such areas, wildlife is protected but the local people are permitted to carry on with their daily life and work.
3. These areas are protected by the local people whose lives are closely related to them. They also conserve these areas and thus help in conserving biodiversity. Grasslands and forests in India harbour some of the rarest species of plants and animals in the world.
4. Through the joint efforts of the Forest Department and the local people, some of these habitats are conserved efficiently because the livelihood of these people is dependent on these habitats.