Welcome Animal kingdom

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Classification of animals

Animalia

TISSUE/ORGANLEVEL/ORGAN SYSTEM.

RADIAL SYMETRY

BILATERAL SYMETRY

CELLULAR LEVEL

PORIFERA

radial

coelenterate

cnidariaAnnelidsArthropodsMolluscsEchinodermataHemichordateschordate

1.Porifera• Members of phylum are known as sponges. Multicellular animals

and have cellular level of organization. Shape of the body is vase or cylindrical.

• Asymmetrically or bilaterally symmetrical body.• Body is perforated by many pores , the Ostia through which the

water enters and oscula through which water posses out.• The pathway of water transport is helpful in food

gathering ,respiratory exchange and removal of waste. The interior of the body is hollow by numerous canals lined with collared flagellated cells or choanocytes.

• Mouth and anus are absent. Skeleton consists of spicules.• Reproduction by asexual and sexual. Posses great power of

regeneration.• Ex: sycon , spongilla and euspongea.

2. Coelenterates (cnidaria)• They are aquatic , marine , sessile or free-swimming.

Multicellular animals with tissue grade of organization.• These are radially symmetrical animals. Cnidaria is derived

from cnidoblasts or cnidocytes present on tentacles of the body. Cnidoblasts are used for anchorage , defense and for the capture of prey.

• Cnidarians exhibit tissue level of organization and are diploblastic . They have a central gastro-vascular cavity with a single opening mouth on hypostome.

• Reproduction is both sexual and asexual. • ex: physalia , adamsia , pennatula , gorgonian and meandrina.

• Ctenophores is commonly , known as sea walnuts or comb jellies are exclusively marine.

• Radially symmetrical , diploblastic organisms with tissue level of organization .

• The body bears eight external rows of ciliated comb plates . Which helps in locomotion .

• Digestion is both extracellular and intracellular . Bioluminescence is well-marked in ctenophores .

• Sexes are not separate . Reproduction takes only by sexual means . Fertilization is external with indirect development .

• Ex: pluerobrachice and ctenoplana.

3. ctenophores

4. Platy helminthes(flatworms)• Platy helminthes are bilaterally symmetrical and dorso-

ventrally flattened flatworms . Triploblastic , acoelomate with blind sac body plan with organ level of organization . Moderately elongated flattened shape .

• Hooks and suckers are fond in the parasitic forms . These are mostly endoparasities found in animals as well as in human beings .

• Some of them absorb nutrients directly from their body surface . Specialised cells are called flame cells help in osmoregulation and excretion .

• Sexes are not separate . Fertilization is internal and development is through many large larval stages .

• Ex: taenia(tape worm), fasicola(liver fluke).

5.Aschelminthes• The body is circular and it is known as round worm . • They may be free living , aquatic and terrestrial or parasitic in

plants and animals . These have organ system level of organization.

• They are bilaterally symmetrical , triploblastic and pseudocoelomates .alimentary canal is well developed muscular pharynx . An excretory tube removes body wastes from the body cavity through excretory pores . Sexes are separate . While female is longer than male .

• Fertilization is internal and development may be direct or indirect .

• Ex: ascaris , wuchiaria (filiaria worm) , ancyclostoma (hook worm)

6. Annelida• They may be aquatic , marine or fresh water , fresh living and

sometimes parasitic. They exhibit organ level of body organization and bilaterally symmetrical.

• They are triploblastic and metamerically segmented and coelomates animals. Their body is distinctly marked out in segments or metamers.

• They posses longitudinal and circular muscles which help in locomotion.

• A closed circulatory system is present nephridia helps in osmoregulation and excretion.

• Their reproduction is sexual .• Ex: neries , pheretima and hirudinaria .

7. Arthropod • Arthropods is triploblastic , coelomates , bilaterally

symmetrical , metamerically segmented animals.• They have organ system level of organization. The body is

covered by chitinous exoskeleton. They have head , thorax and abdomen. They have jointed appendages .

• Respiratory organs are gills , book gills , book lungs or tracheal system. Circulatory system is of open type . Sensory organs like antenna , statocysts or balance organs are present.

• Excretion takes place through malphigian tubules.• Fertilization is usually internal. They are mostly oviparous .

Development may be direct or indirect.• Ex : honey bees (apis) , silkworm (bombxy) , laccifer( lac

insect).

8. Mollusca

• This is the second largest animal phylum . Molluscs are terrestrial or aquatic , marine or fresh water having an organ system level of organization.

• They are bilaterally symmetrical , triploblastic , coelomates animals. Body is covered by a calcareous shell and is unsegmented.

• A soft and spongy layer of skin forms a mantle over the visceral hump. They have respiratory and excretory functions.

• The anterior head region has sensory tentacles . • They are usually oviparous and indirect development.• Ex: pila(apple snail) , pinctada(pearl oyster) , sepia(cuttle fish),Loligo (squid) , octopus(devil fish).

9. Echinodermata• All are marine with organ system level of organization. The

adult echinoderms are radially symmetrical but larvae are bilaterally symmetrical .

• They are triploblastic and coelomate animals. Digestion system is complete with mouths on the lower side and anus on the upper side.

• the most distinctive feature of echinoderms is the presence of water vascular system which helps in locomotion , capture and transport of food and respiration.

• Excretory system is absent.• Sexes are separate . Reproduction is sexual . Fertilization is

usually external . Development is indirect with free swimming larva.

• Ex: asterias (star fish) ,echinus(sea urchin) , antedon(sea lily) , cucumaria(sea cucumber).

10. Hemichordate• This phylum consists of a small group of worm like marine

animals with organ system level of organization.• They are bilaterally symmetrical animals , triploblastic and

coelomates animals .• The body is symmetrical and composed of an anterior

probocis , a collar and a long trunk .• Circulatory system ism of open type . Respiration takes place

through gills . Excretory organ is probocis gland .• Sexes are seprate . Fertilisation is external . Development is

indirect . • Ex:balanoglassus and saccoglassus .

11. Chordates• Animals belonging to phylum chordata are fundamentally characterized by

the presence of notochord , a dorsal hollow nerve cord and paired pharyngeal gill slits.

• These are bilaterally symmetrical ,triploblastic , coelomate , with organ system level of organization .

• They posses a post anal tail and a closed circulatory system .• Phylum chrodata is divided into three subphyla : urochordata,

cephalochordata and vertebra . Subphyla urochordata and cephalochodata are often referred to as prtochodates and are exclusively marine .

• The members of sub phylum vertebrata posses notochord during the embryonic period.

• The notochord is replaced by a cartilaginous or bony vertebral column in the adult .all vertebrates are chordates but all chordates are not vertebrates .

• Vertebrates have a ventral muscular heart with two , three , four chambers , kidneys for excretion and osmoregulation and paired appendages which may be fins or limbs .

1. class-cyclostomata

• All living members of the class cyclostomata are ectoparasites on some fishes. They have an elongated body bearing 6-15 pairs of gills slits for respiration.

• Cyclostomes have a sucking and circular mouth without jaws. Their body is devoid of scales and paired fins . Cranium and vertebral column are cartilaginous .

• Circulation is of closed type . Cyclostomes are marine but migrate for spawning , within a few days , they die. Their larvae , after metamorphosis , return to the oceans .

• Ex: petromyzon(lamprey) ,and myxine(hag fish)

2. class-chondrichthyes• They are marine animals with streamlined body and have cartilaginous

endoskeleton. Mouth is located ventrally. Notochord is persistent throughout the life . Gill slits are separate and without operculum(gill cover)

• The skin is tough , containing minute placoid scales . Teeth are modified placoid scales which are backwardly directed . Their jaws are very powerful .due to absence of air bladder they have to swim constantly to avoid sinking . Heart is two chambered . Some of them have electric organs (torpedo) and some posses poison sting (trygon).

• They are cool blooded animals i.e.; they lack the capacity to regulate their body temprature . Sexes are separate . They have internal fertilization and many of them are viviparous .

• Ex : scoliodon (dog fish) , pristis(saw fish) , carcharodon (great white shark), trygon(sting ray).

3. class-osteichthyes• It includes both marine and fresh water fishes with bony

endoskeleton . Their body is streamlined . Mouth is mostly terminal . They have four pairs of gills which is covered by an operculum on each side.

• Skin is covered with cycloids/ctenoid scales . Air bladder is present which regulates buoyancy.

• Heart is two chambered . They are cool – blooded animals.• Sexes are separate . Fertilization is usually external . They are

mostly oviparous and development is direct .• Ex: exocoetus (flying fish) , hippocampus(sea horse) , catla

(catla) , labeo (rohu) .

4. class-amphibian• Amphibians can live in aquatic as well as terrestrial also . Most

of them have two pairs of limbs . Body is divisible into head and trunk .

• Tail may be present in same . the amphibians skin is moist. The eyes have eyelids . A tympanum represent the ear .alimentary canal , urinary and reproductive tracts open into a common chamber called cloaca.

• Respiration is by lungs , gills or by skin. Heart is three chambered 2-auricle , 1-ventricle. These are cool blooded animals .

• Sexes are separate . Fertilization is external . They are oviparous and development is indirect.

• Ex : bufo(toad) , rana(frog) , hyla(tree frog) , salamander .

5. class- reptilia• The class name is refers to their creeping or crawling mode of

locomotion. They are mostly terrestrial animals and their body is covered by dry and cornified skin , epidermal scales or scutes. They do not have external ear openings . Tympanum represents ear.

• Limbs, when present, are two pairs. Heart is usually three chambered , but four chambered in crocodiles .

• Snakes and lizards shed their scales as skin cast.• Sexes are separate . Fertilization is internal . They are

oviparous and development is direct .• Ex: chelone (turtle) , testudo(tortoise) , chameleon(tree

lizard), calottes (garden lizard).

6.class- aves• The characteristics features of aves are the presence of

feathers and most of them can fly except flightless birds (eg:ostrich).

• They posses beak . The forelimbs are modified into wings. The hind limbs are modified for walking , swimming or clasping the tree branches. Skin is dry without glands expect the oil gland at the base of the tail.

• Endoskeleton is fully ossified(bony) and the long bones are hollow with air cavities(pneumatic).heart is completely four chambered. They are warm blooded animals. Respiration is by lungs .sexes are separate . Fertilization is internal .they are oviparous and development is direct.

• Ex:corvus(crow), columba(pigeon) ,psittacula(parrot) , struthio(ostrich).

7. class-mammalian• They are found in variety of habitats – polar ice caps,

deserts ,mountains ,forests, grasslands and dark caves .the unique mammalian characteristics is the presence of milk producing glands. The skin of mammals is unique in possessing hair.

• External ear is present . Different types of teeth are present in jaws. Heart is four chambered . They are homoithermous. Respiration by lungs . Sexes are separate . Fertilization is internal .

• They are viviparous with few exceptions and development by direct .

• Ex: platypus , kangaroo , flying fox , camel .

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