Test: Biodiversity & Conservation - 2 - Grade 12 MCQ

• The forests occurring in tropical areas of heavy rainfall are known as tropical rain forests. It has abundant species of wildlife and vegetation.
• Previously 14 percent of the Earth’s land surface was covered by the tropical rain forests.

Tomato, potato, Brinjal etc. belongs to genus Solanum although they are of diverse forms. This variation in form represent species diversity belonging to same genus.

‘The Evil Quartet’ is the sobriquet used to describe the reasons for the decline in the number of species. The four reasons include Loss of habitat and fragmentation, Over-exploitation of species, Invasion of alien (new) species and Co-extinctions.

Wetland provide benefits like prevention from flood and recharge ground water, social, economic and environmental benefits and being rich in nutrients, they provide a diverse and productive ecosystem.

Biodiversity can be classified on the basis of community, habitat and landscape but not on the basis of population of particular species in the biosphere.

• The forests occurring in tropical areas of heavy rainfall are known as tropical rain forests. It has abundant species of wildlife and vegetation.
• Currently, 6 percent area of the Earth’s land surface is covered by the tropical rain forests.

The excess and unsustainable use of resources is known as over-exploitation. It is also known as overharvesting. Overexploitation of any kind of resource leads to rapid decline and destruction of that resource that may cause serious damage to the ecosystem.

In food chain, each organism has its own role in flow of energy and nutrient cycle. If snakes become extinct the loss will make the biological network imbalanced. Their gene pool will lost forever that results into loss of biodiversity.

The pattern of species diversity on earth is not uniformly distributed. Species variation is generally highest in the tropics and decreases towards the poles due to variation in temperature.

• The unintentional or deliberate introduction of alien (new) species into a habitat cause the aliens to turn invasive and thus causing the decline or extinction of indigenous species.
• They can affect all types of organisms (animals, plants, fungi, and microorganisms) and ecosystems.

The legal conversion of land into the status of royal forest is a kind of afforestation. This conversion of land is done to protect the particular species endemic to area.

Gene pool is the sum total of gemone of different organism of a particular species. Reduction of gene pool is mainly caused by genetic drift along with reasons like geographical isolations.

• The carrot grass also known as Parthenium is an erect and annual herb. It is responsible for environmental, medical, and agricultural hazards.
• It contains chemicals like parthenin, is toxic to cattle and causes pollen allergy in humans.

• Eichhornia crassipes also known as water hyacinth.
• It was first introduced from South America into China that later on became a serious environmental problem.
• It reduces the sunlight penetration and lowers the oxygen content in the water that hampers the water ecosystem.

Evil quartet are for process that are responsible for loss of biodiversity. It includes fragmentation, overharvesting, introduction of invasive species and habitat degradation. It do not include fission.

The species that had been recently extinct includes Quagga (Africa), Steller’s Sea cow (Russia) and Dodo (Mauritius). Bengal tiger is not extinct so far.

Amphibians group of animals are more venerable to extinction. About 33% of amphibians are facing danger of extinction followed by 23% of mammals and 12% of birds species.

The main cause of accelerated extinction of species diversity loss is the human activities like deforestation, urbanization, industrialization etc.

Loss of biodiversity in a region may leads to ,decline in plant production, lowered resistance to environmental perturbations such as drought and increased variability in certain ecosystem processes.

• The African catfish Clarias gariepinus was introduced for aquaculture purposes.
• The introduction was illegal and posed a threat to the indigenous catfishes in our rivers due to disease introduction, competition, and environmental modification.

Reproductive capacity of an animals is lowered if area of free movement is reduced. So, wild animals do not breed frequently in Zoos. So, statement i is wrong and ii is correct.

If a species experiences 90 percent decline over three generation (about 10 years) would be called as critically endangered species. Critically endangered species should be protected to avoid extinction.

• Co-extinction is the phenomenon that tells, when a species becomes extinct, the plant and animal species also become extinct that are obligatorily associated with the host species.
• If a host is extinct the parasite associated with it is also extinct.

To qualify as a biodiversity hotspot, as per Myers hotspt map, it must contain at least 0.5% or 1500 species of vascular plants as endemics. It must have lost at least 70% of its primary vegetation.

Buffer zone surrounds the core area and is managed to accommodate variety of resources use strategies, research and education.