Odisha BSE HSC Env & Pop Ed key terms

A self-regulating unit in which living organisms interact with one another and with their non-living surroundings, exchanging energy and matter. Examples include a pond, a forest patch, or a grassland.

The two divisions of any ecosystem: biotic components are the living parts such as plants, animals and microbes; abiotic components are non-living factors such as sunlight, water, air, soil and temperature that shape where life can exist.

An organism, chiefly a green plant or alga, that makes its own food by photosynthesis using sunlight, carbon dioxide and water. Producers form the base of every food chain and supply energy to all consumers.

An organism that cannot make its own food and obtains energy by eating other organisms. Herbivores are primary consumers, carnivores that eat herbivores are secondary consumers, and top predators occupy the highest consumer level.

A microorganism such as bacteria or fungi that breaks down dead plants and animals into simpler substances, returning nutrients like nitrogen and phosphorus to the soil for reuse by producers.

A linear sequence showing how energy passes from one organism to the next through feeding, for example grass to grasshopper to frog to snake. Each step is a trophic level and energy decreases at every transfer.

A network of interconnected food chains in an ecosystem, reflecting that most animals eat more than one kind of food and are eaten by more than one predator. It gives a more realistic picture of energy flow than a single chain.

A diagram that represents the numbers, biomass or energy at each trophic level, usually with producers at the base. Pyramids of energy are always upright because energy is lost at each transfer.

The ecological principle that only about ten percent of the energy at one trophic level is passed on to the next, the rest being lost mainly as heat through respiration. It explains why food chains rarely have more than four or five links.

The circulation of chemical elements such as carbon, nitrogen, oxygen and phosphorus between living organisms and the physical environment. These cycles keep nutrients available and make life on earth sustainable.

The conversion of atmospheric nitrogen gas into nitrogen compounds that plants can absorb, carried out by soil bacteria such as Rhizobium in legume root nodules, by free-living bacteria, and by lightning in the atmosphere.

The particular place where an organism naturally lives and finds the food, water, shelter and space it needs, such as a mangrove creek, a rocky shore or a sal forest. Different species occupy different habitats.

The full role a species plays in its ecosystem, including what it eats, when it is active, where it nests and how it interacts with other species. Two species with identical niches cannot coexist indefinitely.

The total mass of living material, usually expressed as dry weight per unit area, in a given trophic level or ecosystem. Biomass pyramids may be inverted, for example in a pond where tiny phytoplankton support larger consumers.

A natural resource that can be replenished by natural processes within a reasonable time, such as solar energy, wind, water, and biomass. Overuse can still exhaust a renewable resource if it is consumed faster than it regenerates.

A resource formed over millions of years, such as coal, petroleum, natural gas and most minerals, which is used up faster than it forms. Once exhausted, it cannot be replaced on a human timescale.

Coal, petroleum and natural gas formed from buried remains of ancient organisms. Burning them releases carbon dioxide and other pollutants, making them the leading human cause of global warming and air pollution.

The removal of the fertile top layer of soil by wind, running water or human activity such as deforestation and overgrazing. It reduces farm productivity and causes silting of rivers and reservoirs.

The large-scale clearing of forest cover for agriculture, settlement, mining or timber. It destroys habitat, accelerates soil erosion, reduces rainfall and releases stored carbon into the atmosphere.

The entire land area that drains rain and snowmelt into a common river, stream or lake. Watershed management combines afforestation, check dams and contour bunding to conserve water and soil within that area.

The collection and storage of rain from rooftops or ground catchments for later use, or for recharging groundwater. It improves water availability in dry months and reduces dependence on tube wells.

Water held in the spaces and cracks of soil and rock below the surface, drawn up through wells and tube wells. Over-extraction in excess of recharge lowers the water table and can cause land subsidence or salt intrusion.

Development that meets the needs of the present generation without compromising the ability of future generations to meet their own needs. It balances economic growth, social welfare and environmental protection.

The presence in the atmosphere of substances such as smoke, dust, sulphur dioxide, nitrogen oxides and carbon monoxide at levels harmful to health, plants and materials. Major sources include vehicles, industry and the burning of fuels.

The warming of the earth's surface because gases such as carbon dioxide, methane and water vapour trap outgoing heat radiation in the atmosphere. Human emissions have intensified it, causing global climate change.

The thinning of the stratospheric ozone layer by chemicals such as chlorofluorocarbons and halons, allowing more harmful ultraviolet radiation to reach the earth. It raises risks of skin cancer and crop damage.

Contamination of rivers, lakes and groundwater by sewage, industrial effluent, fertilisers, pesticides and plastic waste, making water unsafe for drinking and harmful to aquatic life. It can cause diseases such as cholera and typhoid.

Excessive enrichment of a water body with nutrients such as nitrates and phosphates from fertilisers and sewage, causing rapid algal growth. When the algae decay, oxygen is depleted and fish and other aquatic life die.

The gradual build-up of a pollutant such as a pesticide or heavy metal in the body of an organism over its lifetime, and its increase in concentration along the food chain. Top predators receive the highest doses.

Waste that can be broken down by microorganisms into harmless simpler substances, such as vegetable peels, paper and leaf litter. It can be composted, whereas plastics and glass are non-biodegradable and persist for long periods.

The variety of life at all levels, including genetic variation within species, the number of species, and the range of ecosystems such as forests, wetlands and mangroves. High biodiversity makes ecosystems more stable.

A plant or animal species whose numbers have fallen so low that it faces a high risk of extinction in the wild. Examples in India include the tiger, the great Indian bustard and the olive Ridley sea turtle.

The illegal hunting, trapping or capture of wild animals, often for skins, ivory, horns, bones or meat. It is a major threat to endangered species and is punishable under wildlife protection law.

Protecting species in their natural habitat through national parks, wildlife sanctuaries, biosphere reserves and community reserves. It preserves the whole ecosystem and the interactions on which species depend.

Protecting species outside their natural habitat in zoos, botanical gardens, seed banks, gene banks and captive breeding centres. It supplements in-situ protection, especially for critically endangered species.

A large protected area with a core zone kept free from human interference, a buffer zone for research and limited use, and a transition zone for settlements. It combines conservation with sustainable local development.

Teaching and learning about the size, growth, distribution and quality of human populations and how these affect individuals, families, society and the environment. It aims to build informed attitudes and responsible decisions rather than to dictate family size.

The number of live births per 1,000 people in a population in a given year, also called the crude birth rate. It is a basic measure for studying population growth and planning health services.

The number of deaths per 1,000 people in a population in a given year, also called the crude death rate. A falling death rate while birth rates remain high is the main cause of rapid population growth.

The rate at which a population increases or decreases in a year, calculated from births, deaths and net migration. It is usually expressed as a percentage and determines how fast a population doubles.

A very rapid rise in population caused by high birth rates combined with declining death rates due to better health care and food supply. It strains land, water, schools, hospitals and employment opportunities.

The number of deaths of children under one year of age per 1,000 live births in a year. It is a sensitive indicator of health care, nutrition, sanitation and overall living conditions.

The average number of years a person is expected to live, given current death rates. It rises with better nutrition, sanitation, immunisation and health services, and is a key measure of development.

The number of females per 1,000 males in a population. A low sex ratio signals discrimination against girls, including female foeticide and neglect, and has social consequences for marriage and family life.

The percentage of people aged seven years and above who can read and write with understanding. It strongly influences health behaviour, family size decisions, income and women's participation in development.

The overall well-being of people measured by health, education, income, nutrition, housing, sanitation and a clean environment, not by income alone. It falls when population grows faster than services and resources can expand.

A composite measure combining life expectancy, education and per capita income to rank countries by human development. It shows that development is about people's capabilities, not merely economic output.

The maximum population of a species that a given environment can support indefinitely with the available food, water, space and other resources. Exceeding it leads to resource depletion, pollution and a fall in living standards.

The transitional stage between childhood and adulthood, roughly from 10 to 19 years, marked by rapid physical growth, hormonal changes, emotional shifts and new social expectations. It is a period of both opportunity and vulnerability.

The stage at which the reproductive organs mature and secondary sexual characteristics appear, such as voice change and facial hair in boys and breast development and menstruation in girls. It normally begins between 10 and 14 years.

A state of complete physical, mental and social well-being in all matters relating to the reproductive system, including safe motherhood, family planning, prevention of infection and freedom from coercion or violence.

The physical, mental and social well-being of people aged 10 to 19, covering nutrition, anaemia, menstrual hygiene, mental health, substance abuse prevention and protection from early marriage and exploitation.

The voluntary use of knowledge and methods to decide the number and spacing of children. It includes counselling, contraceptive methods and safe motherhood services, and protects the health of mothers and children.

A viral infection that weakens the body's immune system, spread mainly through unprotected sex, transfusion of infected blood, shared needles and from mother to child. There is no cure, but prevention and treatment can control it.

The safe and dignified management of menstruation through clean absorbent material, frequent washing, proper disposal of used pads and accurate information. Poor hygiene raises the risk of infection and often causes girls to miss school.

A condition in which the blood has too few healthy red blood cells, commonly because of iron deficiency, causing tiredness, weakness and poor concentration. Adolescent girls and pregnant women are at highest risk.

Influence from friends and age-mates to adopt certain behaviour, dress or attitudes in order to be accepted. In adolescence it can encourage risky habits such as smoking or substance use, or positive habits such as study and sport.