[Mission 2023] INSIGHTS STATIC QUIZ, 4 July 2022 – Environment

Solution: c)

What are the key elements that lead to so much variation in the physical and chemical conditions of different habitats?

The most important ones are temperature, water, light and soil. We must remember that the physico-chemical (abiotic) components alone do not characterize the habitat of an organism completely; the habitat includes biotic components also – pathogens, parasites, predators and competitors – of the organism with which they interact constantly. We assume that over a period of time, the organism had through natural selection, evolved adaptations to optimise its survival and reproduction in its habitat. Each organism has an invariably defined range of conditions that it can tolerate, diversity in the resources it utilises and a distinct functional role in the ecological system, all these together comprise its niche.

Solution: a)

A constant input of solar energy is the basic requirement for any ecosystem to function and sustain. Primary production is defined as the amount of biomass or organic matter produced per unit area over a time period by plants during photosynthesis.

It can be divided into gross primary productivity (GPP) and net primary productivity (NPP).

Gross primary productivity of an ecosystem is the rate of production of organic matter during photosynthesis. A considerable amount of GPP is utilised by plants in respiration. Gross primary productivity minus respiration losses (R), is the net primary productivity (NPP).

Net primary productivity is the available biomass for the consumption to heterotrophs (herbivores and decomposers).

Secondary productivity is defined as the rate of formation of new organic matter by consumers. Primary productivity depends on the plant species inhabiting a particular area. It also depends on a variety of environmental factors, availability of nutrients and photosynthetic capacity of plants. Therefore, it varies in different types of ecosystems.

Solution: d)

All the species of organisms inhabiting a particular area (land or water) are together termed as BIODIVERSITY or Biological Diversity of that area. In other words, “Species-richness of a place is called as its biodiversity.”

According to the world Resource Institute, IUCN and UNEP (1992) – “Biodiversity is the totality of genes, species, and ecosystems in a region.”

Biodiversity is the term popularized by the socio-biologist Edward Wilson to describe the combined diversity at all the levels of biological organisation. The most important of them are–

(i) Genetic diversity: A single species might show high diversity at the genetic level over its distributional range. The genetic variation shown by the medicinal plant Rauwolfia vomitoria growing in different Himalayan ranges might be in terms of the potency and concentration of the active chemical (reserpine) that the plant produces. India has more than 50,000 genetically different strains of rice, and 1,000 varieties of mango.

(ii) Species diversity: The diversity at the species level, for example, the Western Ghats have a greater amphibian species diversity than the Eastern Ghats.

(iii) Ecological diversity: At the ecosystem level, India, for instance, with its deserts, rain forests, mangroves, coral reefs, wetlands, estuaries, and alpine meadows has a greater ecosystem diversity than a Scandinavian country like Norway.

Solution: a)

Population is a group of organisms usually of the same species, occupying a defined area during a specific time.

Population growth rate is the percentage variation between the number of individuals in a population at two different times. Therefore, the population growth rate can be positive or negative.

Community:

Communities in most instances are named after the dominant plant form.

For example, a grassland community is dominated by grasses, though it may contain herbs, trees, etc.

Solution: b)

The Convention on Wetlands is the oldest of the modern global intergovernmental environmental agreements. The treaty was negotiated through the 1960s by countries and non – governmental organizations concerned about the increasing loss and degradation of wetland habitat for migratory waterbirds. It was adopted in the Iranian city of Ramsar in 1971 and came into force in 1975. 

The Convention’s mission is “the conservation and wise use of all wetlands through local and national actions and international cooperation, as a contribution towards achieving sustainable development throughout the world”.

Wetlands are among the most diverse and productive ecosystems. They provide essential services and supply all our fresh water. However, they continue to be degraded and converted to other uses.

The Convention uses a broad definition of wetlands. It includes all lakes and rivers, underground aquifers, swamps and marshes, wet grasslands, peatlands, oases, estuaries, deltas and tidal flats, mangroves and other coastal areas, coral reefs, and all human-made sites such as fish ponds, rice paddies, reservoirs and salt pans.

There are 49 Ramsar sites in India.