Land as Habitat
& Adaptations
The surface of
the earth is considered to be most variable in terms of time and geography. The
organisms that lives and propagate on land referred as terrestrial organisms.
Examples: Trees, animals, man etc.
It is mainly
associated with the physico-chemical
factors of the environment. The important factors of the habitat are moisture, temperature, air, substratum, interrelationship of population
and geographical barriers. The
habitat is divided into six types namely
ü Prairies
ü Steppe
ü Deserts
ü Forests
ü Tundra’s
ü Caves
Ø
Prairies
It is the intermediate conditions between the forests and open land,
trees are absent. The soil is rich in organic matter and dark in colour, annual
rainfall is 26 – 30 inches.
Examples: Bison, Grass hoppers
, beetles etc.,
Ø
Steppe
It is the region without trees, covered with rough grasses and shrubs in
spring season. In summer, due to drought conditions it becomes like a desert where
as in winter covered with snow. The annual rainfall is 10 – 12 inches.
Examples: Ants, Grasshopper, Termites,
Reptiles, Birds etc.,
Ø
Deserts
The annual rainfall is below 10 inches.
Scarcity of water is the main factor of this region.
·
Plants:
They have succulent stems which help to store the water with small and narrow
leaves or without leaves. When leaves are absent, stem acts as leaf to carry
out photosynthesis and if leaves are
present they are covered with a wax layer which prevents the evaporation of
water.
Examples: Cactus, Opuntia etc.,
·
Animals:
Camels develop a device in the body
to store the water. Lizard’s eye
lids modify into plates and in rattle snake
colour helps in warming and defending.
Ø
Forests
The annual rainfall exceeds 80 -90
inches and the temperature is fairly uniform throughout the year and are
divided into three types as follows
·
Tropical
rain forests
The warm and wet makes up the climate, the annual rainfall is 80 – 90 inches and the average temperature
is 60 - 70⁰f.
Examples
ü
Invertebrates:
Snails, Scorpions, Spiders etc.,
ü
Vertebrates:
Chameleons,Elephants,Monkeys etc.,
·
Deciduos
forests
The precipitation makes up the climate, annual rainfall is 30 – 60 inches and the average
temperature is 50 - 60⁰f.
Examples
ü
Invertebrates:
Worms, Snails, Insects etc.,
ü
Vertebrates:
Tree frogs, Owls, Wood peckers etc.,
·
Coniferous
forests
The green conifers make up the climate, annual rainfall is 40 – 60 inches and the average temperature
is 40 - 60⁰f.
Examples
ü
Invertebrates
: Wasps, Beetles, Saw flies etc.,
ü
Vertebrates
: Squirrels, deers, foxes etc.,
Ø
Tundra’s
These are the wet arctic grass lands with
low temperature and little precipitation.
ü Vegetation : Lichens , Mosses’, Hedges
etc.,
ü Animals: Musks, Reindeers, Polar bears
etc.,
ü Birds: Geese, Duck, Plovers etc.,
Ø
Caves
It is a natural underground space large enough for human to enter. These
are formed naturally by the weathering
of rock and often extend into the underground.
They are devoid
of pigmentation, eyes are absent, body
is long and slender.
Examples
ü Mollusks: Shell is thin
ü Fishes: Scale less
ü Arthropoda : Poorly developed
exoskeleton
