Revision: Biodiversity, Conservation and Environmental Issues Biology HSC Science (General) 12th Standard Board Exam Maharashtra State Board

Biodiversity is defined as the variety of plant and animal life in the world or in a particular habitat, a high level of which is usually considered to be important and desirable

The sum total of species richness, i.e., the number of species of plants, animals and micro-organisms inhabiting in a given habitat, is known as biodiversity.

It is a tool used to classify organisms based on their similarities and differences.

Hotspot is a biodegradable region that is both a significant reservoir of biodiversity and is threatened with destruction.

Eutrophication: The process by which a body of water enriched in dissolved nutrients (such as phosphates) that stimulates the growth of aquatic algae usually resulting in the depletion of dissolved oxygen.

Ramsar Sites: It is a wetland site designed of international importance under the Ramsar convention. It is an inter-governmental environmental treaty established in 1971 by UNESCO and coming into force in 1975.

The diversity of life forms present on Earth, including plants, animals, and microorganisms, is called biodiversity.

Species that completely disappear from the planet are referred to as extinct.

Species that are not native to a region or locality but are unintentionally or purposefully introduced and cause harm to the native species already present are referred to as invasive species.

When a species possesses a very high risk of extinction as a result of rapid population decline of 50 to more than 70 per cent over the previous 10 years, it is said to be an endangered species.

Noise is defined as any unpleasant, loud, undesired sound that interferes with one’s hearing and concentration, and the pollution caused by noise is termed noise pollution.

Noise is defined as any unpleasant/loud undesired sound interfering with one's hearing and concentration and the pollution caused due to noise is termed as noise pollution.

The heating-up of the earth’s atmosphere due to trapped infrared rays reflected from the earth's surface by atmospheric gases is called the greenhouse effect.

The warming up of the atmosphere due to trapping of the solar radiation reflected by the earth by gases like carbon dioxide is called Greenhouse effect.

The gradual increase in the average surface temperature of the Earth due to rising concentrations of greenhouse gases in the atmosphere is called global warming.

Deforestation is the conversion of forested areas into non-forested areas for agricultural, industrial, urban or other human uses.

The gradual increase in Earth’s average surface temperature due to rising concentrations of greenhouse gases in the atmosphere is called global warming.

Cryopreservation is a technique in which organisms, tissue, and cells are preserved and stored at the very low temperature of liquid nitrogen (−196°C) for years. They remain viable in the frozen state for future use.

• Habitat loss and fragmentation due to agriculture, deforestation, urbanisation, and industrialisation is the major cause of biodiversity loss.
• Over-exploitation of plants and animals for food, trade, medicine, and luxury items leads to rapid decline and extinction of species.
• Alien species invasion disturbs native ecosystems by competition, predation, and disease (e.g., water hyacinth, Nile perch).
• Pet trade and illegal wildlife trade result in large-scale removal and death of species from their natural habitats.
• Co-extinctions occur when the extinction of one species leads to the loss of other dependent species.