Animalia Kingdom

Introduction

· The organisms, which are eukaryotic, multicellular, and heterotrophic, are categorized as Animalia kingdom.

· The organisms of Animalia kingdom have no cell-wall.

· Most of animals of Animalia kingdom are mobile.

Classification of Animalia Kingdom

· Based on the extent and type of the body design differentiation, Animalia kingdom classified as −

o Porifera

o Coelenterata

o Platyhelminthes

o Nematoda

o Annelida

o Arthropoda

o Mollusca

o Echinodermata

o Protochordata

o Vertebrata

§ Pisces

§ Amphibia

§ Reptilia

§ Aves

§ Mammalia

· Let’s discuss each of them in brief −

Porifera

· The literal meaning of ‘porifera’ is the organisms with holes.

· The organisms of porifera are non-motile and attached to some solid support.

· The examples of this group are Sycon, Spongilla, Euplectelia, etc.

Coelenterata

· Organisms of coelenterata group live in water.

· The organisms of this group have cavity in their bodies.

· Hydra and sea anemone are the common example of coelenterate.

Platyhelminthes

· The organisms of this group do not have true internal body cavity or coelom; so, they neither have well-developed organs.

· The bodies of organisms of this group are flattened from top to bottom; therefore, they are also known as flatworms.

· Planareia, liverfluke, tape worm, etc., are the typical examples of this group.

Nematoda

· The organisms of nematode have cylindrical body.

· The organisms have tissue, but as such no well-developed body (i.e. no real organ).

· The filarial worms (causing elephantiasis disease), roundworm in the intestines, etc., are the common examples of nematodes.

Annelida

· The organisms of annelida group live almost everywhere including fresh water, marine water as well as on land.

· Earthworms, nereis, and leeches are the familiar examples of annelida.

Arthropoda

· Arthropoda, probably, is the largest group of animals.

· The animals of this group don’t have well defined blood vessels rather there is an open circulatory system.

· The literal meaning of arthropod is jointed legs; so, they have jointed legs.

· Prawns, butterflies, houseflies, spiders, scorpions, etc. are the typical examples of arthropod.

Mollusca

· The organisms of mollusca are invertebrate.

· Most of the organisms of Mollusca group live in water.

· Snails and mussels are the typical example of Mollusca.

Echinodermata

· The organisms of Echinodermata have spiny skinned.

· Echinodermata are free-living marine organisms.

· The examples of echinodermata are starfish, sea urchins, feather star, etc.

Protochordata

· The organisms of protochordata are normally marine. E.g. Balanoglossus, Herdemania, and Amphioxus

· The organisms of protochordata show a typical feature of body design, called as notochord; however, it does present there throughout the life.