ENVIRONMENT FOR UPSC PRELIMS 2020 , SOLUTION OF TEST-3

1 . Solution: (b)
Species diversity refers to the variety of species within a region.
Species richness (simplest measure of species diversity) refers to the number of species per unit area

2 . Solution (b)
Crocodiles tend to live in saltwater habitats, while alligators hang out in freshwater marshes and lakes.

3 . Solution (a)
The main drawback of social forestry was –
The programme has been found to benefit only the rich farmers, who can plant crops that can be rotated in short durations and find a ready market. Eucalyptus is grown extensively under this programme because it is a cash crop and gives fuel wood. But eucalyptus cultivation has proved to be an ecological disaster. This is because no other plant can grow near eucalyptus trees and they take up a lot of ground water, so much so that the water table is lowered, soil nutrients are depleted and the soil gets degraded in course of time.

4 . Solution (a)
Ganges River dolphin (Status – IUCN: Endangered)
The Ganges River dolphin, or “susu” or “soons”, inhabits the Ganges-Brahmaputra-Meghna and Karnaphuli-Sangu river systems of Nepal, India, and Bangladesh.
They are often known as the “Tiger of the Ganges”, the river dolphin is an indicator animal and has the same position in a river ecosystem as a tiger in a forest, its presence indicating a sign of a healthy river ecosystem.

5 . Solution (a)
Angiosperms: it comprises of the plants that have flowers and produce seeds enclosed with in a carpel.
Algae: Algae are a type of plant-like living things that can make food sunlight by photosynthesis.
Bryophytes: They are ‘non-vascular plants’, such as mosses, hornworts and liverworts. They do not have a true vascular tissue.

6 . Solution (d)

7 . Solution (a)
Pitcher plants are capable of photosynthesis but it is not enough to for their nutrient requirement. So they gather it by ingesting other insects.
They are found in rain forests of North East India.

8 . Solution (b)

9 . Solution (d)
Algae as Food: Algae are important as a source of food for human beings, domestic animals and fishes. Species of Porphyra are eaten in Japan, England and USA. Ulva, Laminaria, Sargassum and Chlorella are also used as food in several countries. Sea weeds (Laminaria, Fucus, Ascophyllum) are used as fodder for domestic animals.
Algae in Agriculture: Various blue green algae such as Oscillatoria, Anabaena, Nostoc, Aulosira increase the soil fertility by fixing the atmospheric nitrogen. In view of the increasing energy demands and rising costs of chemically making nitrogenous fertilizers, much attention is now being given to nitrogen fixing bacteria and blue green algae. Many species of sea weeds are used as fertilizers in China and Japan.
Algae in Industry: Agar – agar is used in the preparations of some medicines and cosmetics. It is obtained from the red algae Gelidium and Gracillaria.
A phycocolloid Alginic acid is obtained from brown algae. Algin is used as emulisifier in ice creams, tooth pastes and cosmetics.
Idodine is obtained from kelps (brown algae) especially from speicies of Laminaria.
Algae in space travel: Chlorella pyrenoidosa is used in space travel to get rid of Co2 and other body wastes. The algae multiplies rapidly and utilizes the Co2 and liberate 02 during photosynthesis. It decomposes human urine and faeces to get N2 for protein synthesis.

10 .  Solution (c)
‘Hangul’ or Kashmir stag is not confined to the Dachigam National Park of Kashmir. It is found in northern reaches of Chamba Valley of H.P. as well.
Hangul is not a member of “Red deer” family anymore. It belongs to Asian clade of Elk and it is   classified as critically endangered by IUCN .