With the help of an aquatic food chain, explain biomagnification of DDT and its effect on the occupants of the highest trophic level.

OR

(a) What is in-situ conservation?

(b) Write the basis on which certain areas have been designated as ‘Hot spots’ and ‘Sacred groves’ respectively.

(c) Mention any two ‘Sacred groves’ and any two ‘Hot spots’ in India

Biomagnification is increase in concentration of the toxin at successive trophic levels. The toxin gets accumulated because a toxic substance cannot be metabolised or excreted, and is thus passed on to the next higher trophic level along a food chain.

Example of DDT (dichlorodiphenyltrichloroethane) and other heavy metals such as mercury and cadmium are the toxins that cause biomagnifications. In the aquatic ecosystem the concentration of DDT increases at successive trophic levels if it starts at 0.003 ppb (ppb = parts per billion) in water, it can ultimately can reach 25 ppm (ppm = parts per million) in fish-eating birds, through biomagnification.

That is DDT is present in low amount in water and reaches a high concentration in fish-eating birds through biomagnifications.

High concentrations of DDT disturb calcium metabolism in birds, which causes thinning of eggshell and their premature breaking, eventually causing decline in bird populations.

OR

(a) In-situ is a type of conservation. In-situ conservation is conservation of genetic resources in natural populations of plant or animal species. When we conserve and protect the whole ecosystem, its biodiversity at all levels is protected - we save the entire forest to save the tiger. This approach is called in situ (on site) conservation.

(b) ‘Hotspots’ is certain region selected for maximum protection. The region with very high levels of species richness and high degree of endemism (i.e., species confined to that region and not found anywhere else). These regions are regions of accelerated habitat loss.

Sacred groves are refuges for a large number of rare and threatened plants. In many cultures, tracts of forest were set aside, and all the trees and wildlife within were venerated and given total protection such regions are known as Sacred Groves.

(c) Sacred groves of India 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.

Hotspots of india are found in Western Ghats and Sri Lanka, Indo-Burma and Himalaya.