ecology & bio environment geography section 1 MCQ Questions & Answers Detailed Explanation

Answer: (c)

In ecology and biology, abiotic components (also known as abiotic factors) are non-living chemical and physical factors in the environment, which affect ecosystems. Abiotic phenomena underlie all of biology.

From the viewpoint of biology, abiotic factors can be classified as light or more generally radiation, temperature, water, the chemical surrounding composed of the terrestrial atmospheric gases, as well as soil.

The macroscopic climate often influences each of the above. A renewable resource is a natural resource with the ability to reproduce through biological or natural processes and replenished with the passage of time. Renewable resources are part of our natural environment and form our ecosystem.

Answer: (c)

Green accounting is a type of accounting that attempts to factor environmental costs into the financial results of operations.

It has been argued that gross domestic product ignores the environment and therefore decision-makers need a revised model that incorporates green accounting.

Answer: (c)

A food chain is a linear sequence of links in a food web starting from a trophic species that eats no other species in the web and ends at a trophic species that is eaten by no other species in the web.

A food chain differs from a food web because the complex polyphagous network of feeding relations are aggregated into trophic species and the chain only follows linear monophagous pathways. A common metric used to quantify food web trophic structure is food chain length. In its simplest form, the length of a chain is the number of links between a trophic consumer and the base of the web and the mean chain length of an entire web is the arithmetic average of the lengths of all chains in a food web.

Food chains were first introduced by the African-Arab scientist and philosopher Al-Jahiz in the 9th century and later popularized in a book published in 1927 by Charles Elton, which also introduced the food web concept.

Answer: (d)

Forests are considered as sinks of carbon dioxide. A carbon sink is anything that absorbs more carbon that it releases, whilst a carbon source is anything that releases more carbon than is absorb. It is for this reason that they are indispensable in the present global scenario marked by increasing global warming and climate change.

Answer: (a)

Productivity is the rate of organic matter or biomass production. The average ocean productivity is about 50 grams of carbon per square meter per year; while, the average land productivity is 160 grams of carbon per square meter per year.

Salt marshes and mangroves have one of the highest productivity of 3300-6000 grams of carbon per square meter per year.

So the correct sequence of the ecosystem in the order of decreasing productivity is:

Mangroves > Grasslands > Lakes > Oceans.

Answer: (c)

The greenhouse effect is a process by which thermal radiation from a planetary surface is absorbed by atmospheric greenhouse gases such as Carbon dioxide, and is re-radiated in all directions.

Since part of this re-radiation is back towards the surface and the lower atmosphere, it results in an elevation of the average surface temperature above what it would be in the absence of the gases. Human activities, primarily the burning of fossil fuels and clearing of forests, have intensified the natural greenhouse effect, causing global warming.