Though the conflict between humans and wildlife started with the evolution of man, the intensity of conflict has increased due to the activities of modern man. Justify your answer with suitable examples.
The humans first evolved around 2.5 million years ago and agriculture began about 11 thousand years ago. It is since then that humans have started to exploit the forest land for agriculture. Development in medical technology has increased the lifespan of humans, decreased the mortality rate of mother and child, further aggravating the problem of human population.
Along with this, the industrial revolution caused enormous consumption of earth's resources but giving back nothing. The monumental amount of waste is destroying the natural habitat of other species, be it aquatic or terrestrial, endangering and later causing extinction thereof.
This is how human activities have led to the increase in conflict between humans and wildlife.
What is an ecosystem service? List any four important ecosystem services provided by the natural ecosystems. Are you in favour or against levying a charge on the service provided by the ecosystem?
Ecosystem Services
The products of ecosystem processes are termed as ecosystem services. Forests are the major sources of ecological services. Some of the ecosystem services they provide are
(i) Purification of air and water.
(ii) Mitigating droughts and floods.
(iii) Cycling nutrients.
(iv) Generating fertile soils
(v) Providing wildlife habitat.
(vi) Maintenance of biodiversity.
(vii) Pollination of crops.
(vii) Providing storage site for carbon.
(ix) Providing aesthetic, cultural and spiritual values.
Robert Constanza and his colleagues tried to put price tags on nature's life support services, which was about US $\$ 33$ trillion a year. No, i am not in favour of levying a charge on ecological services but it is very important, to understand how much nature is providing us for free and if we overuse or misuse its resources, we'll have to pay a heavy price for it.
Describe the consumptive use value of biodiversity as food, drugs and medicines, fuel and fibre with suitable examples.
Biological resources are the basis of life forms on this planet. The countries with maximum biodiversity possess better potential to compete with the rest of the world. Biodiversity has great economic importance to mankind due to its many uses, some of, which with consumptive value are following
Food is obtained from biodiversity sources like livestock, forestry and fish. Biodiversity in modern agriculture is beneficial due as a source of new crops. e.g., just three cereals crop like wheat, rice and maize account for about $55 \%$ of protein and $60 \%$ of calories in humans.
Drugs such as morphine (Papaver somniferum), quinine (Cinchona ledgeriana), reserpine (Rauwolfia vomitaria), belladonna (Atropa belladonna), aconite (Aconitum, napellus), wintergreen and birth bark (Gaultheria procumbens) are derived from plants.
About $70-80 \%$ of entire population is dependent on plants or its extract for medicine. penicillin (Penicillium notatum), tetracycline (bacteria), digitalin (Digitalis) are some examples of medicinal plants.
Plant like Chorchorus, Gossypium are sources of fibre while Jatropha is a source of biofuels. Fossils fuels (e.g., petrolum) are obtained from fossils of organisms.
Species diversity decreases as we move away from the equator towards the poles. What could be the possible reasons?
Species diversity decreases as we move towards the poles, because
(i) Temperature decreases and conditions become harsh.
(ii) Both the amount and intensity of solar radiation decreases.
(iii) Vegetation decreases.
(iv) Less resources available to support species.
Speciation is generally a function of time and environmental stability, so if conditions are too harsh, it is difficult for the species to survive and adapt. This results in decrease in biodiversity towards the poles.
Explain briefly the 'rivet popper hypothesis' of Paul Ehrlich.
Ecologist Paul Ehrlich gave rivet popper hypothesis to help understand the contribution species richness. He compared each species with rivet in the body of an airplane.
(i) This hypothesis explains that ecosystem to be an airplane and the species to be the rivets joining all parts together.
(ii) If every passenger travelling in the airplane start taking rivets home (causing a species to become extinct), initially it may not affect flight safety (proper functioning of ecosystem), but over a period of time the plane becomes weak and dangerous (species become endangered and then extinct.