How do scientists extrapolate the total number of species on earth ?
There are two methods to estimate and extrapolate the number of species on earth
(i) The primary method used by the scientists to extrapolate the number of species on earth is the estimation rate of discovery of new species.
(ii) Total number of species can also be extrapolated by the statistical comparison of the tropical and temperate species richness of exhaustively studied groups of insects. The ratio is then extrapolated with existing species of plants and animals to predict the gross estimate of the number of species on earth.
Humans benefit from diversity of life. Give two examples.
(i) Humans derive numerous economic benefits directly from diversity of organisms.
(a) Food products (cereals, pulses and fruits).
(b) Firewood.
(c) Fibre (cotton, jute from plants and silk, wool from animals).
(d) Construction material (timber for making furniture, houses and sports goods).
(e) Industrial products (tannins, lubricants, dyes, resins and perfumes).
(f) Products of medicinal importance (about 25000 plants are used in traditional medicine).
(ii) There are huge intangible benefits that humans derive from the diversity of life.
(a) Pure oxygen.
(b) Natural pollinators.
(c) Flood and soil erosion control.
(d) Nutrient replenishment.
(e) Waste recycling by microbes and other insects, etc.
(f) Aesthetic pleasure and mental peace.
List any two major causes other than anthropogenic causes of the loss of biodiversity.
The two major causes other than anthropogenic causes of the loss of biodiversity are
(i) Alien Species Invasions When alien species are introduced unintentionally or deliberately in a habitat, some of them can cause decline or extinction of indigenous species.
(ii) Co-extinctions When a species becomes extinct, the plant and animal species associated with it, in an obligatory way, also become extinct.
What is an endangered species? Give an example of an endangered plant and animal species each?
An endangered species is a population of organisms, which is facing a high risk of becoming extinct because
(i) Its number being very low.
(ii) It is threatened by changing environment.
(iii) It is facing predator threat.
Endangered plant species-Venus fly trap
Endangered animal species-Siberian tiger
What are sacred groves and their role in biodiversity conservation?
Sacred groves are sacred tracts which are held in high esteem by local communities. The sacred groves are dedicated to local deities or ancestral spirits and are protected by local communities through social traditions and taboos that incorporate spiritual and ecological values.
Sacred groves represent native vegetation in a natural or near natural state and are thus, rich in biodiversity and harbour many rare species of plants and animals.
Such sacred groves are found in Meghalaya (Khasi and Jaintia hills), Aravalli hills of Rajasthan, Western Ghats, regions of Karnataka and Maharashtra and Madhya Pradesh (Bastar, Chanda and Sarguja region).