Unit 2-Lesson 8-GRASSLAND and DESERT ecosystems

Grasslands Ecosystem: 

Grassland, are area in which the vegetation is dominated by a nearly continuous cover of grasses. Grasslands occur in environments conducive to the growth of this plant cover but not to that of taller plants, particularly trees and shrubs. 

• Distribution: Grasslands are areas dominated by grasses. They occupy about 20% of the land on the earth surface. Grasslands occur in both in tropical and temperate regions where rainfall is not enough to support the growth of trees. Grasslands are known by various names in different parts of the world.

Place                  Name of the grassland

NorthAmerica                      Prairies

Eurasia (Europe andAsia)   Steppes

Africa                                   Savanna

SouthAmerica                       Pampas

India Grassland,                   Savanna

Grasslands are found in areas having well defined hot and dry, warm and rainy seasons. Tropical grasslands are commonly called Savannas.They occur in easternAfrica, South America,Australia and India. Savannas form a complex ecosystem with scattered medium size trees in grass lands.

             

                                                             Grassland of South Africa

• Flora and fauna: Grasses are the dominating plants with scattered drought resistant thorny trees in the tropical grasslands. Badgers, fox, ass, zebra, antelope are found grazing on grasslands support the dairy and leather industries. Grasslands also support large population of rodents, reptiles and insects.

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Deserts Ecosystem :

Desert are arid land with usually sparse vegetation; especially : such land having a very warm climate and receiving less than 25 centimeters (10 inches) of sporadic rainfall annually and/or an area of water apparently devoid of life.(merriam-webster.com)

• Distribution: Deserts are hot and low rain areas suffering from water shortage and high wind velocity.They show extremes of temperature. Globally deserts occupy about 1/7thof the earth’s surface. 

• Flora and fauna: Cacti, Acacia, Euphorbia and prickly pears are some of the common desert plants. Desert animals include shrew, fox, wood rats, rabbits, camels and goat are common mammals in desert. Other prominent desert animals are, reptiles, and burrowing rodents insects.

 ACACIA TREE

CACTUS 

• Adaptations: Desert plants are hot and dry conditions.

(i) These plants conserve water by following methods:

• They are mostly shrubs.

• Leaves absent or reduced in size.

• Leaves and stem are succulent and water storing.

• In some plants even the stem contains chlorophyll for photosynthesis.

• Root system well developed spread over large area.

(ii) The animals are physiologically and behaviorally adapted to desert conditions.

• They are fast runners.

• They are nocturnal in habit to avoid the sun’s heat during day time.

• They conserve water by excreting concentrated urine.

• Animals and birds usually have long legs to keep the body away from the hot ground.

• Lizards are mostly insectivorous and can live without drinking water for several days.

• Herbivorous animals get sufficient water from the seeds which they eat.

Camel is known as the ship of the desert as it can travel long distances without drinking water for several days.

DESERT ANIMALS