Biodiversity - class-XII

If we accept May's global estimates only 22% of the total species have been recorded so far. If May's proposal for discovery of new species is accepted then there are probably more than 1,00,000 plant species and more than 3,00,000 animal species yet to discovered and described.

Species diversity is the variety in the number and richness of the species of a region, Western Ghats have greater amphibian species diversity as compared to eastern ghats.

Vertical distribution of different species occupying different levels is called stratification. For example, trees occupy top vertical strata or layer of a forest, strubs the second and herbs and grasses occupy the bottom layers.

There are four major causes of biodiversity losses which are collectively called as the evil quartet. These are habitat loss and fragmentation, over exploitation, alien species invasion and co-extinctions. 

Alexander Von Humboldt observed that within a region richness increased with increased explored area, but only upto a limit. If a graph is plotted between species richness and area then we get a rectangular hyperbola. ON a log scale, the relationship becomes linear (straight line) and is described by the equation,

Brazil is the country with the highest biodiversity in the world. One-tenth of the world's overall species lives here.

Tropical region occurs at 23$^o$ N and 23$^o$ S. The region is present at the equator. It is limited in latitude by the tropic of cancer in the north and the tropic of capricorn in the south.

Pines seeds are mainly small and winged, and are anemophilous generally, which means that the seeds are dispersed by wind. However, some seeds are larger and they have only a vestigial wing and are needed to be dispersed by a bird. Thus, If at high altitudes, birds become rare, the plants likely to disappear are Pine plants. Oaks are not generally found at such high altitudes.

The tree line in the Himalayas generally increases in altitude from east to west due to variations in precipitation and temperature, but the Eastern Himalayas are often cited for specific high-altitude vegetation zones; however, this is a complex biogeographical question where the Eastern Himalayas typically host higher biodiversity and distinct altitudinal limits.

Nepenthes khasiana is a pitcher plant endemic to the Khasi Hills in the state of Meghalaya, India.

India is a mega-biodiverse country, and it is estimated to account for approximately 7-8% of the world's recorded species.

Ecological amplitude refers to the range of environmental conditions (tolerance) under which a species can survive and reproduce successfully.

The rate of photosynthesis would be maximum at the equator because the the rate of photosynthesis depends on the light intensity. Maximum intensity of light occurs at the equator, and gradually decreases with increasing distance from the equator to the south and north poles. So the correct answer is 'Equator'.