(i) Biodiversity conservation, Ecosystem protection.
(iii) Educate people not to harm biodiversity.
(iii) Forest would be destroyed, many species of plants and animals lost.

Alien species are species that have been introduced from another geographic region to an area outside its natural range. For example; Parthenium, Lantana and Eicchornia are invaded the native species of India and causes environmental damage. Introduction of African catfish Clarias gariepinus in India for aquaculture purpose is posing threat to many indigenous catfish.

Details of rivet popper hypothesis emphasizing the loss of rivets on the wings of an aeroplane, less of key species that drive major ecosystem function is a serious threat.

Earth Summit held at Rio de Janerio and World Summit on sustainable development held in 2002 in Johannesburg South Africa where 190 countries pledged their commitment to achieve by 2010, a significant reduction in the current rate of biodiversity loss at global, regional and local levels.

i) Ethical
ii) Narrowly utilitarian
iii) Broadly utilitarian

Less variation in productivity from years to years, resilient to occasional disturbances, resistant to invasions by alien species. Tilman found that plots with more species showed less year to year variations in total biomass & increased diversity contributed to higher productivity.

S – species, A – area, Z – slope of the line (regression coefficient), C – Y intercept. Z value is 0.1 to 0.2 Value 1.15 indicates larger suitable areas for species diversity.

(a) EI Nino. It is an abnormal warming of surface ocean waters in the eastern tropical Pacific. It is called the Southern Oscillation. The Southern Oscillation is the see-saw pattern of reversing surface air pressure between the eastern and western tropical Pacific; When the surface pressure is high in the eastern tropical Pacific it is low in the western tropical Pacific, and vice-versa. Because the ocean warming and pressure reversals are, for the most part, simultaneous, scientists call this phenomenon the EI Nino/Southern Oscillation or ENSO for short.

Unfortunately not all EI Nino's are the same nor does the atmosphere always react in the same way from one EI Nino to another. This is why NASA's Earth scientists continue to take part in international efforts to understand EI Nino events. Hopefully one day scientists will be able to provide sufficient warning so that we can be better prepared to deal with the damages and changes that EI Nino causes in the weather.

(i) Hot spots of biodiversity. The concept of 'Hot-spots' was developed by Norman Myres (1988) to designate specific areas for in-situ conservation. The conservation the hot spots are the richest and most threatened reservoirs of plants and animal life on earth.
The criteria for determining hot spots are:
1. Number of endemic species.
2. Degree of threat which is measured in terms of habitat loss.
There are 25 hot spots in the world out of which two are in India. They are Western Ghats and eastern Himalayas.
Hot spot of Eastern Himalayas are active centres of evolution and rich in diversity of flowering angiosperms. Western Ghats have semi evergreen forests. Western Ghats include two main centres of biodiversity i.e. Agastyamalai hills and Silent valley.
(ii) Ex-situ conservation. It means maintenance of off site collections either in gardens by farmers, botanical garden for storing seeds, genes, pollen, tissue culture etc.
The rare plants have been found to flourish in large numbers under the care and protection of gardeners and nature lovers.
The farmers have been maintaining genetic diversity (enormous varieties) of crop plants since ancient times by saving seeds or other components for the next plantings.
Collection of samples of cultivated and wild varieties of plants and storing them in botanical gardens is another method of conservation of germplasm.
In seeds, the living meterial remains in metabolically suspened state. When the seeds are to be stores for longer periods, it is necessary to avoid conditions which favour respiration and enzymatic actions.
(iii) India's effort in biodiversity conservation. India has greatly contributed to conservation of biodiversity owing to its great utility and need for conservation. The following measures have been taken for this purpose:
1. Setting up bodies like Indian Board for Wildlife, Bombay Natural History  etc.
2. observation of first week of October as national wildlife week.
3. Introduction of Wildlife Protection Act in 1972.
4. Setting up of sanctuaries, national parks and biosphere reserves.

Since plants cannot move away from their predators (herbivores) and harsh environmental conditions, many of them have become extinct. But animals can move away from the harmful/unfavourable environments or their predators and evolution of favourable characters has thus taken place in them.