Monday, 23 March 2015

Animal facts and also the Category, Division and Classification of Animal Kingdom

Humans since their childhood are fond of Animals around them neither wild nor Domestic. Animals that surround us are created by God for our happiness and also to support our survival. Animal Kingdom ensures the survival of Humans by providing some necessary basic survivals things for us such as Food (meat), Wool, stabilizes the eco system and ensures pollination for survival of plants which in turn ensures our survival. Hence such Animal Kingdom must be protected and conserved. Now let’s see the Classification of Animal Kingdom.

What is an Animal?

Animals are living organisms found in nearly all of the earth’s habitats and surface, including the depths of the oceans, the freezing Arctic and even inside other animals and plants. They are made up of many cells. Most move actively but some are sedentary which means fixed and hence move only their body parts. Animals like humans take food for their survival. They have sensors and nervous systems that enable them to detect what is happening around them and respond immediately.

Category, Division and Classification of Animal Kingdom

Categories of Animals

More than a million and a half species of animal have been identified and also there are many million more yet to be discovered. The animal kingdom is classified into many division based on some categories. The categories on which the Animal Kingdom is classified are:
  • Based on Backbone
  • Based on phylum
  • Based on feeding

Classification of Animal Kingdom based on Backbone

The Animal Kingdom is classified on the basis of backbone as follows:
  • Invertebrates
  • Vertebrates
Invertebrates are Animals without backbones such as snails, lobsters etc… while vertebrates are Animals with backbones such as lions, monkeys etc…Invertebrates make up 97% of all the animal species.

Classification of Animal Kingdom based on Phylum

Invertebrate and Vertebrate Classification

Under Invertebrates and Vertebrates, Animals are classified into groups according to their similarities and whether they have common ancestors. There are 35 major groups called phyla which mean singular Phylum. Each Phylum is divided into sub-groups. Now let’s see the smallest of these classifications which contains 9 divisions that consists animals of just one type.
Hence based on the Phylum Animal kingdom is classified as:
  • Phylum Arthropoda
  • Phylum Annelida
  • Phylum Chordata (Vertebrate Classification)
  • Phylum Cnidaria
  • Phylum Echinodermata
  • Phylum Mollusca
  • Phylum Nematoda
  • Phylum Platyhelminthes
  • Phylum Porifera

Among above Classification Phylum Chordata is the only division that contains vertebrates which means animals with back bone.

Phylum Arthropoda

Arthropoda are the largest groups of Animals. Nearly more than one million species have been identified under Phylum Arthropoda. They include insects, crustaceans (such as crabs), arachnids (such as spiders) and centipedes.

Phylum Annelida

There are about 12,000 species of animals under the Phylum Annelida, each of which has a body made up of segments with a mouth at one end and an anus at other end. Animals in the Phylum Annelida include earthworms, marine bristle worms such as rag worms and leeches.

Phylum Chordata (Vertebrate Classification)

Phylum Chordata consists of 48,000 species of Animals. Most of them are vertebrates such as Fish, Amphibians, Reptiles, Birds and Mammals. Vertebrates are the most advanced animals.

Phylum Cnidaria

Under Phylum Cnidaria more than 9,000 species are discovered, most of which are found in the sea. Phylum Cnidaria include jellyfish, sea anemones, hydras and corals. Cnidarians catch food using tentacles armed with stinging threads called nematocysts.

Phylum Echinodermata

All Echinoderms live in the sea. Phylum Echinodermata includes more than 6,500 species that contains sea urchins and starfish. Most of these species have five parts radiating from a central point, hard plates under their skin and many tube-feet.

Phylum Mollusca

Phylum Mollusca form a highly diverse group. More than 50,000 species have been identified under this phylum. This Phylum includes snails and slugs, mussels and clams and squids and octopuses. These animals are soft bodied and may be protected by a shell. Most of them live in water but some such as snails are found on land.

Phylum Nematoda

Nematoda are referred to as parasites that dwell in plants and animals. Nematoda also called as roundworms have a thin cylindrical body that is pointed at both ends. They are found in many habitats and occur in very large numbers in soil.

Phylum Platyhelminthes

Under this Phylum there are more than 19,000 species including tapeworms. Phylum Platyhelminthes are parasites that shelter in the human body and also other animals. Flatworms also come under this Phylum and they have a flattened body with one opening, the mouth on the upper side.

 Phylum Porifera

Phylum Porifera are the simplest animals in the Animals Kingdom that includes Sponges. These species live in the sea attached to rocks and other objects. More than 5,000 species have been identified under this category. Water is drawn in through the pores of the sponges and bits of food are filtered out and eaten by the sponge’s cells.

In the Above classification of Animals only Phylum Chordata comes under the classification of Vertebrates which includes:
  • Mammals
  • Birds
  • Fish and Amphibians
  • Reptiles


Mammals are vertebrates and they come under the class of Mammalia. Mammals are animals which feed their young ones with milk and give birth to young ones. Mammals breathe by their lungs. Mammals are warm blooded animals and nurse their babies with milk from mammary glands. This Characteristic is strictly a mammal thing. Mammals are covered by hair throughout their body and they are also called as endothermic species. Humans are also included under the category of mammals as they give birth and nurse their young ones. Animals like lion, tiger, Whales and even dolphins are mammals. Mammals have a capacity to adapt to the external temperature and conditions; hence they are called as warm blooded animals. There are 21 orders of Mammalia, they are:
  • Monotremata (platypus)
  • Marsupialia (Kangaroo)
  • Artiodactyla (sheep, camel)
  • Carnivora (cat, wolf, bear)
  • Cetacea (Whale)
  • Chiroptera (Bat)
  • Dermoptera (Flying Lemur)
  • Endentata (Anteater)
  • Hyracordea (Hyrax)
  • Insectivora (Mole)
  • Lagomorpha (Rabbit)
  • Macroscelia (Elephant Shrew)
  • Perissodactyla (Horse, Zebra)
  • Pholidata (Pangolin)
  • Pinnipedia (Seal, walrus)
  • Primates (Human, Monkey)
  • Proboscidea (African and Asian Elephants)
  • Rodentia (Mouse)
  • Sirenia (Dugong)
  • Tubulidentata (Aardvark)
  • Xenarthra (Sloth, Armadillo)


Reptiles are too vertebrates but are different from other vertebrates. They do not require water to reproduce while fish and Amphibians need water to reproduce. Reptiles are covered by scales for protection. Most reptiles lay eggs while some give birth to young ones on land. Retiles do not have the ability of regulating their body temperature according to the external atmosphere hence they are called as exothermic species or cold blooded animals. Reptiles as Mammals also breathe by their lungs while some breathe by their skin if needed like amphibians. Eyesight of reptiles are sharp, some reptiles like crocodiles have good night vision. There are 4 different orders of Class Reptilia, they are:
  • Testudine (Turtles and Tortoises)
  • Squamata (Lizards and Snakes)
  • Crocodilia (Crocodiles and alligators)
  • Rhynchocephalia (Tuataras)

Huge flying reptiles named as pteranodon which had a wing span of 8m lived millions of years ago.


Birds are highly specialized species with amazing adaptations. There are about 6000 species of birds around the world. Most birds have hollow bones which give them light weight and help them to fly in air. Also birds have thicker bones that support them in running on ground. The skin of birds is covered by feathers rather than hair. Birds lay eggs in nests and provide warmth for eggs to hatch. Birds lack teeth but are created with beak which helps them in various operations like eating and feeding food to young ones. Birds migrates form one place to another while mating and also for environmental conditions.

Fish and Amphibians

Fishes live in water and get oxygen through their gills located on the sides of their mouth. Water passes over the tiny network of blood vessels which take in oxygen. Fishes have an external covering of scales which is a thin layer of protective plates. Fishes use their fins to keep balance and lay eggs to give birth. Amphibians have four legs and have moist, slimy skin or dry, warty skin. Amphibians breathe air by their lungs and also absorb oxygen by their skin. Without water they would suffocate. They live both in water and land. Amphibians and Fishes need water for reproduction.

Classification of Animal Kingdom based on Feeding

Animals are classified into 3 types based on their feeding, they are:
  • Herbivorous
  • Carnivorous
  • Omnivorous

Animals that feed only on plants are called as herbivorous. Example: Giraffe
Animals that feed only on other animals are called as Carnivorous. Example: Lion, tiger
Animals that feed both on plants and animals are called as Omnivorous. Example: Humans

Hope you learned about the classification of Animal Kingdom by the above facts and you enjoyed it…please subscribe if you like it and stay tuned for more Incredible facts…!

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