Revision: Environmental Management Science and Technology 2 SSC (English Medium) 10th Standard Maharashtra State Board

Biodiversity is the richness of living organisms in nature due to the presence of varieties of organisms, ecosystems and genetic variations within a species.

The richness of living organisms in nature due to the presence of varieties of organisms, ecosystems, and genetic variations within a species is called biodiversity.

The variation among individuals of the same species, such as differences seen in human beings, is called genetic diversity.

The presence of innumerable species of organisms in nature, including various types of plants, animals, and microbes, is called species diversity.

The existence of different ecosystems formed through interactions between organisms, their habitat, and environmental changes is called ecosystem diversity.

Regions of the Earth that are extremely rich in species, especially endemic species, and are under severe threat of habitat loss are called biodiversity hotspots.

• An ecosystem (a term coined by A.G. Tansley in 1935) is a self-sustaining unit where living (biotic) and non-living (abiotic) components continuously interact and exchange energy.
• It is structurally composed of abiotic factors (physical/chemical elements like sunlight, water, and soil) and biotic factors (all living organisms).
• The living organisms are divided by their roles into producers (synthesise food), consumers (feed on others), and decomposers (recycle nutrients from dead matter).
• Ecosystems are classified by their origin into natural (forests, oceans) or artificial/man-made (crop fields, aquariums) and by habitat into terrestrial or aquatic.
• Every ecosystem operates through four core functions: productivity (biomass generation), decomposition, a unidirectional energy flow, and continuous nutrient cycling.

1. Environment includes all physical, chemical, and biological factors that affect living organisms, and is divided into natural and artificial environments.
2. Biotic and abiotic components interact continuously in the environment, and their study is known as ecology.
3. An ecosystem is the basic functional unit of ecology, consisting of biotic and abiotic factors interacting in a defined area.
4. Natural cycles like the water cycle, carbon cycle, and nitrogen cycle help maintain environmental balance.
5. Humans must preserve nature and maintain ecological balance, as Earth is a shared responsibility for current and future generations.

1. Environmental pollution is caused by unnatural changes in air, water, or soil due to human actions like industrialization, deforestation, and overuse of resources.
2. Humans, being intelligent and resourceful, have heavily exploited nature; now, it is their responsibility to restore environmental balance.
3. Public awareness is essential, as many harmful actions toward the environment happen unknowingly.
4. The Forest (Conservation) Act, 1980 restricts forest land use without central government permission; violation can lead to 15 days imprisonment.
5. The Environmental Protection Act, 1986 and Wildlife Protection Act, 1972 enforce limits on pollution and ban trade/use of rare wild animals, with strict penalties for violations.

1. Jadav Molai Payeng, a forest worker from Assam, began planting trees at the age of 16 after witnessing the death of snakes due to floods.
2. He continued tree planting even after a government project ended, eventually converting 1360 acres of barren land into forest over 30 years.
3. His dedication earned him the Padma Shri award, and the forest is now famously known as ‘Molai Jungle’.

• Biodiversity hotspots are highly threatened regions prioritised for conservation due to their massive numbers of endemic species found nowhere else on Earth.
• Globally, 34 identified hotspots cover just 2.3% of the Earth's surface but harbor 50% of the world's plant species, and protecting them could reduce global mass extinction by nearly 30%.
• India hosts two major biodiversity hotspots, the Western Ghats and the Eastern Himalayas, which possess incredible biological wealth but are suffering from accelerated habitat loss.
• The Western Ghats are severely endangered by mining and natural gas exploration, which directly threatens the natural habitats of the Asiatic lion and wild bison.
• Major Indian heritage sites like Manas and Sunderban National Parks are under extreme pressure from dams, deforestation, and water exploitation, endangering their native tiger and rhino populations.

• The World Conservation Union (IUCN) evaluates and categorises species at risk of extinction based on their population decline, habitat quality, and geographical distribution.
• Historically, species were classified into seven broad conservation categories: extinct, endangered, vulnerable, rare, threatened, intermediate, and out of danger.
• The modern IUCN framework evaluates extinction risk using precise quantitative criteria, such as the rate of population decline, population size, and the extent of the geographic range.
• Under the updated system, species are placed into specific risk levels, ranging from Extinct (EX) and Critically Endangered (CR) to Least Concern (LC).
• 'Endangered' species face rapid population decline and immediate survival threats, whereas 'rare' species naturally possess small populations localised in restricted geographical pockets.
• Notable examples of endangered species in India include the Asiatic lion, Indian Rhinoceros, Hornbill, and the medicinal plant Rauwolfia serpentina.
• The Great Indian Bustard is a prime example of a highly endangered species; heavy hunting for its flesh has drastically reduced the population of this large ground bird.