Ch 15Biodiversity, Conservation and Environmental Issues — Class 12 Biology, concept-first.

Diversity is the very essence of life on Earth -- a vast array of microorganisms, algae, fungi, plants and animals occupies every terrestrial and aquatic habitat, showing endless variation in size, sh…

Diversity is the hallmark of life on Earth -- from microorganisms and algae to fungi, plants and animals, living things show remarkable variation in size, shape, mode of nutrition, habitat, reproducti…

Genetic diversity is intraspecific diversity -- the variation found within a single species. It includes the diversity in the number and type of genes and chromosomes present, as well as variation in…

Species diversity is interspecific diversity -- the number of different species of plants and animals found in a given region.

Ecosystem or ecological diversity refers to the different types of ecosystems and habitats found within a given geographical area, each with its own distinctive, interlinked community of species shape…

Beyond simply cataloguing how much diversity exists, ecologists have identified consistent patterns in how that diversity is distributed across the globe.

With the exception of arid, semi-arid and some aquatic habitats, biodiversity across the globe generally follows both a latitudinal and an altitudinal gradient.

Scientists have long tried to establish a quantitative relationship between the diversity of species in a habitat and the size of that habitat, reasoning that larger areas can typically support more r…

It is worth asking whether all this diversity really matters -- what would happen if a few species were permanently lost? A community is generally considered stable if its average biomass production s…

There is no firm consensus on exactly how many species exist on Earth or how many occur in India. Although more than 1.5 million species had been formally documented according to IUCN data as of 2004,…

The loss of biodiversity disturbs the overall balance of an ecosystem, and its most serious consequence is the outright extinction of species.

Ecologists commonly group the main human-driven causes of biodiversity loss into four categories, popularly called 'The Evil Quartet'.

The International Union for Conservation of Nature and Natural Resources (IUCN) maintains the Red Data Book, also called the Red List, which records the conservation status of plant and animal species…

Conservation of biodiversity means the protection, upliftment and scientific management of biodiversity so as to maintain it at an optimum level while still deriving sustainable benefits from it, both…

The case for conserving biodiversity can be grouped into three broad kinds of reason.

In-situ conservation protects a species by protecting its natural habitat -- literally, conservation 'at home'.

When a species becomes critically endangered, additional, more direct measures are sometimes needed to protect it -- this is ex-situ conservation, in which living organisms are protected away from the…

India took part in the Earth Summit at Rio de Janeiro and became a party to the Convention on Biological Diversity (CBD, 1992).

The explosive growth of human population, coupled with rapid industrial development over the last ten decades, has caused a rampant loss of natural resources and disturbed the delicate balance between…

Because respiratory surfaces are in constant contact with the surrounding air, any unfavourable change in air quality directly affects the respiratory system; the severity of harm depends on the conce…

Under the Air (Prevention and Control of Pollution) Act, 1981 (amended in 1987), noise is legally classified as a form of air pollutant.

Water availability has always been a key factor controlling the distribution and density of living things in an area, and human consumption of water has risen sharply with industrialisation.

Solid waste covers everything discarded from homes, offices, shops, schools and hospitals -- municipal solid waste is typically a mix of paper, food waste, plastic, glass, metal, rubber, leather and t…

The greenhouse effect is the natural process responsible for warming the Earth's surface and atmosphere -- without it, the planet's average temperature would be around -18 degrees Celsius rather than…

Ozone is a form of oxygen that is continuously generated and broken down (photo-dissociated) in the stratosphere through the absorption of short-wavelength ultraviolet radiation, following the reactio…

Deforestation is the conversion of forest land into non-forest land. Globally, an estimated 40% of tropical forest has been lost, compared with only about 1% in temperate regions, and the picture in I…

Mission Harit Maharashtra was an ambitious afforestation project launched by the Government of Maharashtra in 2016, aiming to plant 50 crore (500 million) trees over four years, with yearly planting t…

Sample papers and previous-year board questions for this subject.