Classifying the living organisms using appropriate
methods of classification
There are millions of organisms living on earth. They are differ from various things.These organisms could be classified under various methods. Then we can learn easy about them. In modern classification, organisms are classified under three domains.
Groups of organisms
* Animals
* Plants
* Micro-organisms
Animals are categorised into two main groups. It is based on the presence or absence of a vetebral colomn.
Vertebrates
(presence of a vetebral colomn)
* Pisces
* Amphibia
* Reptilia
* Aves
* Mammalia
Invertebrates
(absence of a vetebral colomn)
* Coelenterata
* Annelida
* Mollusca
* Arthopoda
* echinodermata
VERTEBRATES
Pisces (Fish)
* Adapted to living in water.
* Streamlined body shape.
* Possess gills for breathing and fins for swimming.
* They have internal skeleton.
* Two chambered heart.
* Body covered with scales.
Amphibia (Amphibians)
* Adapted to living in water and land.
* Lungs, moist skin and bucal cavity used for gaseous exchange.
* Possess a soft. moist skin with glands.
* They have limbs with webbed fingers.
* Three chambered heart.
Reptilia (Reptiles)
* Adapted to live on land (terestrial).
* They have lungs for gas exchange.
* Possess a dry, scaly skin without glands.
* They have limbs with webbed fingers.
* Four chambered heart (partially divided ventricles).
- Pisces, Amphibia and Reptilia are cold blooded animals.
Aves (Birds)
* Adapted to live on land, water and air.
* Streamlined body shape.
* They have lungs for gas exchange.
* Possess a beak. No teeth in mouth.
* Body covered with feathers.
* Four chambered heart.
* Lay eggs.
* Fore limbs are modified as wings.
* Hind limbs are adpted for walking or swimming.
Mammalia (Mammals
* Different species adapted to live on land, water and air.
* They have lungs for gaseous exchange.
* Possess external ear lobes.
* Skin covered with hair.
* Four chambered heart.
* Young ones feed on breast milk.
- Aves and Mammalia are warm blooded animals.
INVERTEBRATES
Coelenterata (Enidaria)
* Adapted to living in water.
* Cylindrical or unfolded umbrella (Medusa) shaped body.
* Possess a segmented body.
* Radial symmetry.
* Body cavity has only one opening.
Annelida (Segmented worms)
* Live in wet environments.
* Possess a soft body.
* Bi-lateral symmetry.
* Segmented body.
* Possess hard bristles called chaetae.
* Wet body covering.
* Body cavity has a coelom.
Mollusca (Soft bodied animals)
* Live in water and wet environments.
* Possess a soft unsegmented body.
* Wet body covering.
* Some species possess a harder outershell.
Arthropoda (Animals with jointed limbs)
* Live in water and land.
* Possess jointed limbs.
* Segmented body.
* Each segment bears a pair of appandages.
* Possess a hard chitinous exoskeleton.
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