Tejinder Kaur, Academic Content Creator at Edumarz
R.H. Whittaker in 1969 gave the five kingdom classification of organisms. The five kingdoms are Monera, Protista, Fungi, Plantae and Animalia.
Animalia-
This kingdom consists of animals.
Features of Animalia:
Multicellular eukaryotes
Absence of cell wall
Heterotrophic mode of nutrition
Sexual or asexual mode of reproduction
The different phylums of kingdom Animalia are:
Porifera
Coelenterata (Cnidaria)
Platyhelminthes
Nematoda
Annelida
Arthropoda
Mollusca
Echinodermata
Hemichordata
Chordata
Phylum Porifera:
The word porifera is derived from “poros” meaning holes i.e. they include animals having pores all over the body.
They are commonly called sponges.
Habitat is mostly marine, only a few are fresh water.
They are non motile, multicellular, asymmetric organisms.
Have pores all over the body and body made up of a hard shell like skeleton made up of calcium carbonate.
The body is not differentiated into body parts.
No specialized system for digestion, respiration, circulation and excretion.
Pores over the body lead to a characteristic “water canal system” which helps in all major metabolic processes.
Example : Sycon, Spongilla
Phylum Coelenterata
The word Colenterata is derived from a Greek word “kilos” meaning a hollow belly i.e. the body is hollow.
The body has two ends, anterior and posterior. Anterior end consists of the mouth and the posterior end consists of anus.
Habitat is aquatic.
The body consists of two layers of cells, the inner layer and the outer layer and hence called diploblastic.
Exists in two forms: polyp (solitary) and medusa (Colony).
Example: Hydra, Sea anemone
Phylum Platyhelminthes
They are commonly called flatworms because their body is dorso ventrally flattened and is leaf-like.
The body is made up of three layers of cells i.e. triploblastic.
They do not have a coelom i.e. no body cavity lined by mesoderm. Hence called Acoelomate.
The body can be divided into two equal parts from a single body axis, so called bilateral symmetrical.
The body is differentiated and the organ system is developed.
They live either freely or are parasitic i.e. feed on hosts.
Example: Tapeworm, planaria
Phylum Nematoda
They are commonly called roundworms because their body is cylindrical like.
They are bilaterally symmetrical and consist of three body layers of cells hence called triploblastic.
They are called pseudocoelomates as they have a body cavity but are not lined by mesoderm i.e. false body cavity.
They are parasitic and are disease causing. Example: Elephantiasis caused by Wuchereria.
Sexual dimorphism is seen in them i.e. the male and female can be easily differentiated.
Example: Ascaris, Wuchereria.