NEET Practice Questions (MCQs) with Answers & Solutions

(b) IUCN stands for International Union for the Conservation of Nature.

(d) The major threat to human population is population explosion and climatic changes including deforestation and pollution.

(a) The Amazon rainforest is a moist brodleaf forest that covers most of the Amazon basin of South America. This region includes territory belonging to nine nations. The majority of the forest is contained within Brazil, with 60% of the rainforest, followed by Peru with 13% and with minor amounts in Columbia. Venezuela, Ecuador, Bolivia, Guyana, Surinam, and French Guiana. States or departments in four nations bear the name Amazonas after it. The Amazon represents over half of the planet's remaining rainforests, and comprises the largest and most species rich tract of tropical rainforest in the world.

Sacred groves are found in Khasi and Jaintia Hills in Meghalaya, Aravalli Hills of Rajasthan, Western Ghat regions of Karnataka and Maharashtra and the Sarguja, Chanda and Bastar areas of Madhya Pradesh. In Meghalaya, the sacred groves are the last refuges for a large number of rare and threatened plants.

(page-267)

‘Biodiversity hotspots’ are the regions with very high levels of species richness and high degree of endemism that is, species confined to that region and not found anywhere else.

(page- 266)

A keystone species is the one which has a very prominent effect in the ecosystem it inhabits. They play a very important role in determining the structure, number and types of several other species in the ecosystem.

For example- Jaguar is a predator which feeds on more than 80 different species of animals and thus control the balance in forest ecosystem.

Biodiversity hotspots’ are the regions with very high levels of species richness and high degree of endemism(threatened species) that is, species confined to that region and not found anywhere else.

(page-266)

The species-area relationship states that the number of species found in a given area increases as the area increases. This is because larger areas tend to have more diverse habitats and resources, allowing for a greater variety of species to thrive.

The exotic species introduced in India which caused the environmental damage and posed threat to native species are weed species like carrot grass (Parthenium), Lantana and water hyacinth (Eicchornia). The recent illegal introduction of the African catfish Clarias gariepinus for aquaculture purposes is posing a threat to the indigenous catfishes in our rivers.

(page-265)