• Arctic Tundra Food Wed 

It is a well-balanced food web. This region gets slanting sunrays means very little sunlight in which lichens, grasses, and wildflowers grow and form the first trophic level as a producer. In the second trophic level herbivores who depend on the producers for survival like Arctic Hare, Musk ox, Lemming is the primary consumers. Carnivores who eat the herbivore are-Hawk, Polar Bear and Wolf. They are above the herbivores in a food pyramid. They are secondary consumers.

(i) The extinction of species (flora and fauna) due to human and natural influences is called loss of biodiversity.
(ii) The biodiversity loss has a great impact on mankind and also affects land, water, air etc.
(iii) Habitat destruction due to deforestation, population explosion, pollution and global warming are the major cause for loss of biodiversity.
(iv) Sometimes, habitat loss is so severe or happens so quickly that it results in a species being eliminated from the planet.

(i) Bio diversity refers to a wide variety of Iiving organisms, which live in a habitat.
(ii) It is highly influenced by topography, climate as well as human activities.

(i) An ecosystem is a community, where all living organisms live and interact with one another and also with their non-living environment such as land, soil, air, water etc.
(ii) Ecosystems range in size from the smallest units (Eg: bark of a tree) that can sustain life to the global ecosystem or ecosphere. (Eg: Cropland, Pond ecosystem, Forest ecosystem, Desert ecosystem etc.).
(iii) Biosphere harbours all ecosystems on the earth and sustains life forms including mankind.

(i) Biosphere, the fourth sphere of the Earth, is a life supporting layer that exists on the earth's surface.
(ii) This layer on earth encompasses the Lithosphere, Hydrosphere and Atmosphere.
(iii) It includes flora and fauna that thrive on or near the earth's surface.
(iv) Biosphere harbours all ecosystems on the earth and sustains life forms including mankind