9th Class Science Diversity in Living Organisms Animalia


Category : 9th Class

*       Animalia


These organisms are multicellular and heterotrophic. Most of them can move from one place to another and lacks ceil wall in their cell. They are further classified on the basis of body design and cell structures. Some of the phylum of the animal kingdom are discussed below:


*            Porifera

These organisms have smallest holes on their bodies and are non motile in nature. These small holes on their bodies forms the canal system in the body and helps in circulating water, oxygen, and food. They have hard outer covering on their body and are mainly founded in marine water. They are multicellular and diploblastic which have radial symmetry. They do not have any well developed organs like mouth, body cavity, and anus.



*              Coelenterata

They are multicellular and diploblastic animals having more organized tissue structure. Their body shows radial symmetry and are mostly founded in marine water, except for few, such as. Hydra. They have only cells of nervous system and can reproduce by both sexual and asexual methods. They possess central

gastrovascular cavity which consist of mouth surrounded by short and slender tentacles. Some of them live in colonies while other live independently. For example the jelly fish and Hydra shows independent existence.



*           Platyhelminthes

Their bodies shows bilateral symmetry and dorsoventrally flattened animals. Their bodies are triploblastic and have digestive cavity with a single opening called mouth. They have suckers for taking food and hooks for movements.

They do not have any circulatory system. They are either free living or parasitic in nature. For example, planaria are free living and liver flukes are parasitic in nature. They are also hermaphrodite i.e. both the sex male and female are present in the same individuals. They do not have true internal body cavity.



*             Nematoda

Their bodies shows bilateral symmetry and are triploblastic. Their bodies have tissues and have true body cavity, but no real organs. The body is covered with tough resistant cuticle that provides their bodies some sorts of shape and structure. Male and female are found in different individuals. Most of them are parasitic, but very few are free living. For example round worm, filarial worms are parasitic in nature.



*             Anneelida

These organisms show bilateral symmetry and are triploblastic. They also have true body cavity. The body is covered with thin cuticles and have lateral appendages for locomotion. They have alimentary canal in the form of tube like structure which extends from mouth to anus. They have nephridia for removal of waste and nervous system consists of dorsal brain and a ventral nerve chord having ganglia and lateral nerve in each segment of the body. They are either aquatic or terrestrial. For example earth worms and leeches.



*             Arthropoda

The body of the organism is bilaterally symmetrical and are triploblastic. The body is divided into two parts, head and thorax. The head part consists of brains, and sense organs. They have open circulatory system and hence blood does not flow in a well defined blood vessels. The male and female sex are usually different and shows internal fertilization. They are free living or parasitic in nature. They are the largest phylum of the animal kingdom. For example housefly, spider, butterfly, cockroach, etc.



*             Mollusca

These organisms have bilateral symmetry with little segmentation on their body. They have open circulatory system and have kidney like organ for excretion and have foot for movement. They respires by gills and have sensory organ of touch, smell, vision, and taste. The male and female are in different organisms and are mostly aquatic in nature. For example , etc.



*             Echinodermata

These organisms have radial symmetry and are triploblastic and unsegmented body. They have spines on their skins and are free-living marine animals. They have complete digestive system and excretory system is absent. They reproduce by both sexual and asexual mode. Some of them even reproduce by regeneration. Male and female are on different organisms. They have hard outer covering made up of calcium carbonate. For example starfish and antedon.



*             Protochordata

These organisms are bilaterally symmetrical, triploblastic and coelom. They have bag like soft bodies. They have notochord in their bodies having dorsal tubular nerve chord. They are hermaphrodite and are exclusively marine animals. Adult have cellulose covering over their bodies.



*             Vertebrate

The vertebrate have true vertebral column and internal skeleton which provides them a definite body design. They are bilaterally symmetrical, triploblastic and have segmented body. They have notochord and a dorsal nerve chord. They have pair of gill pouches. The vertebrated are further classified into five

groups as pisces, amphibia, reptilia, aves, and mammals.

(A) Pisces: These are fishes and are exclusively aquatic animals with their skins covered with scales. They obtained oxygen dissolved in water using gills. They have streamlined body and muscular tails which is used for movement. They are cold blooded animals and hearts is two chambered. They reproduce by lying eggs. The skeletons is entirely made up of cartilage tissue. The digestive system is with J -shaped stomach and intestine with spiral valves. They have well developed sense of smell, vibration reception and electro reception. Their size varies from few mm to several meters.


(B) Amphibia: The amphibians are the groups of animals having chordates which lives on land as well as in water. They have three chambered heart and respire through gills or lungs. They reproduce by laying eggs i.e. oviparous and fertilization is external in case of frogs and toads, but internal in salamanders and apoda. They have mucus gland in the skin and are cold blooded animals. They have two pairs of pentadactyl.


(C) Reptilia: The reptials are the cold blooded animals having scales on their skins and breaths through lungs. Most of them have three chambered heart, but few of them like crocodiles have four chambered heart. They have two pairs of limbs with pentadactyl and respires through lungs. Teeth are present in almost all of them. They reproduce through internal fertilization and most of them lay eggs i.e. oviparous, but few reptiles are viviparous like lizard and snakes.

(D) Aves: The aves are the warm blooded animals with four chambered heart. Their body is covered with feathers and two forelimbs is modified into wings which helps them in flight. They respires through lungs. Bone have air cavity and hence are light which helps them to fly. Body is divided into head, neck, trunk and tail. They are oviparous and reproduce by laying eggs. The fertilization is internal.


(E) Mammalia: The mammals are warm blooded animals having four chambered heart and breath through lungs. They are viviparous and are breast feeding to their young ones. They have sweat gland on their body and also have hair on their skins. They have external ear which helps them

to hear sounds from the surroundings. They have two pairs of pentadactyl limbs which are variously adapted for walking and running. They respires through lungs. They have internal fertilization and penis is always present. The parents take care of their young one.





         Which one of the following comes in the categories of Coelenterata?

(a) Sycon

(b) Hydra

(c) Spongilla

(d) Planaria

(e) None of these


Answer: (b)



        Match the following in the column A and B given below:

Sl. No. Groups Name of Animals
1. Porifera (a) Hydra
2. Coelenterata (b) Ascaris
3. Annelida (c) Euplectelea
4. Nematode (d) Leech


(a) 1-a, 2-c, 3-d, 4-b

(b) 1-c, 2-a, 3-d, 4-d

(c) 1-b, 2-c, 3-d, 4-a

(d) 1-a, 2-d, 3-c, 4-b

(e) None of these


Answer (b)



      Identify the groups to which the figure given belongs:

(a) Mollusca

(b) Annelida

(c) Nematoda

(d) Porifera

(e) None of these


Answer: (a)



        Which one of the following comes in the categories of amphibians?

(a) Rohu

(b) Hydra

(c) Buffo

(d) Planaria

(e) None of these


Answer: (c)



          Which one of the following comes in the categories of viviparous?

(a) Cobra

(b) Sea Horse

(c) Ostrich

(d) Women

(e) None of these


Answer: (d)




  • The branch of science which deals with the classification of organisms is called taxonomy.
  • The basic unit of classification is species.
  • There are five kingdom of classification as monera, protista, fungi, plant and animals.
  • Plant kingdom is further subdivided as thallophyte, bryophyte and pteridophyta.
  • Animal kingdom is further subdivided as vertebrates and invertebrates..

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