4 ANIMAL KINGDOM - edukad.inedukad.in/wp-content/uploads/2018/01/pdfresizer.com-pdf-resize.pdf · Phylum Protozoa (Unicellular Protists) :-• There are about 15,000 species of protozoans

Terminologies Related to Animal Classification :-Metazoa :-

• Animal groups are characterized by mobility and the presence of a sensory or anervous system. These sys-tems receive stimuli from the environment and ani-mals respondby exhibiting some behavior.

• The only exception is of poriferans (pore-bearers) or the sponges. They have no cell thatcan be termed as nerve cell.

• Like plant life, early animal life also arose in sea. The animals which live on the sea floor arecalled ben-thonic (e.g., echinoderms, corals, and deep sea fishes), whereas those whichswim about actively in sea are called nektons.

• The multicellular eukaryotic organisms with holozoic mode of nutrition are called metazoans.Based on the complexity of organization, metazoans are further sub-divided into two sub-kingdoms, Parazoa and Eumetazoa.Parazoa : Parazoa include the sponges in which cells are loosely aggregated and do not formtissues or organs.Eumetazoa : Eumetazoa include the rest of animals in which cells are organized into structuraland functional units called tissues, organs, and organ systems.

Levels of Organization:-

1. Cellular level :-• Though all members of Animalia are multicellu-lar, all of them do not exhibit the same

pattern of cell organization. For example, in sponges, the cells are arranged as loosecell aggregates, i.e., they exhibit cellular level of organization.

• Some division of labor (activities) occurs among the cells.2. Tissue level :-

• In coelenterates and ctenophores, the arrangement of cells is more complex.• Here, the cells performing the same function are arranged into tissues. Hence, it is

called tissue level of organization.3. Organ level :-

• A still higher level of organization, i.e., organ level is exhibited by the members of Platyhel-minthes and other higher phyla where tissues are grouped together to form organs, eachspecialized for a particular function.

ANIMAL KINGDOM4

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Animal Kingdom


• In animals such as annelids, arthropods, molluscs, echinoderms, and chordates, organshave asso-ciated to form functional systems, each system concerned with a specificphysiological function. This pattern is called organ system level of or-ganization. Organsystems in different groups of animals exhibit various patterns of complexities.

• For example, the digestive system in Platyhel-minthes has only a single opening to theoutside of the body that serves as both mouth and anus, and is hence called incomplete.

• A complete digestive system has two openings, mouth and anus.• Similarly, the circulatory system may be of two types: open type and closed type.

Different types of body symmetry

Open type :-• In this type of circulatory system, the blood is pumped out of the heart and the

cells and tissues are directly bathed in it. The blood is pumped by the heart into theblood vessels that open into blood spaces (sinuses).

• There is no capillary system (e.g., in most arthropods, non-cephalopod molluscsand tu-nicates). These sinuses are actually the body cavities and are calledhemocoel.

• The pressure of the blood is low; it moves slowly between the tissues and, finally,re-turns to the heart via open-ended blood ves-sel.

Closed type :-• Many invertebrates and all the vertebrates, including humans, have a closed

circulatory system. In closed type, the blood flows inside the body through a seriesof blood vessels of varying diameter (arteries, veins, and capil-laries).

• In this system, the same blood regularly cir-culates in the body under highpressure and returns back to the heart without leaving the system of tubes.

Symmetry :-Based on the basis of their body symmetry, animals can be cat-egorized as follows:Radial symmetry : When any plane passing through the central axis of the body divides theorganism into two identical halves, it is called radial symmetry (Fig. 4.1a). The animals withradial symmetry are put in the group Radiata, e.g., cnidarians (hydra and jelly fish). Biradialsymmetry is present in sea anemone, ctenophores.

Animal Kingdom


Bilateral symmetry : The animalswith bilateral symmetry are put in the group Bilateria.The body can be divided into identical right and left halves in only one plane (Fig. 4.1b). Forexample, platyhelminthes, annelids,arthropods, etc. (platyhel-minthes to chordates).Asymmetry : Asymmetric organisms cannot be divided along any plane to produce twoequivalent halves. Sponges are mostly asymmetrical.

Germ Layers :-Germ layers give rise to all the tissues/organs of a fully formed individual. On the basis of thenumber of germ layers, animals can be diploblastic or triploblastic.Diploblastic : In diploblastic animals, the body cells are ar-ranged in two layers—an outerectoderm and an inner endo-derm—with an intervening undifferentiated mesoglea, e.g.,coelenterates.Triploblastic : The body wall in animals is made of three germ layers, i.e., ectoderm,mesoderm, and endoderm, e.g., platyhel-minthes to chordates.

Germinal layers : (a) diploblastic and (b) triploblastic

Body Plan :-Though diverse in shape and size, animals have body that fits in one of the three basic plans:Cell aggregate : Cell aggregate type of body plan is present in sponges. They are clustersof cells with a rudimentary division of labor among them. There are no tissues or organs.Blind sac : Blind sac type of body plan is present in Platyhel-minthes and Coelenteratawhere the alimentary canal has only one opening.Tube within tube : Tube-within-tube type of body plan is pre-sent in Nemathelminthes,Annelida, Arthropoda, Mollusca, Echinodermata, and Chordata. The digestive system is acon-tinuous tube with an opening at both ends.

Animal Kingdom


Body Cavity or Coelom :-The presence or absence of cavity between the body wall and gut wall is very important forclassification.Eucoelomates : True coelom is a body cavity which arises as a cavity in embryonicmesoderm. In this case, the mesoderm of the embryo provides a cellular lining, called coelomicepi-theliumor peritoneum, to the cavity. The coelom is filled with coelomic fluid secreted bythe peritoneum. True coelom is found in annelids, echinoderms, and chordates. True coelomis of two types:

1. Schizocoelom : It develops by the splitting up of meso-derm. It is found in annelids, arthropods,and molluscs. The body cavity of arthropods and non-cephalopod molluscs is called hemocoel.

2. Enterocoelom : The mesoderm arises from the wall of the embryonic gout or enteron ashollow outgrowths or enterocoelomic pouches. It occurs in echinoderms andchordates.Pseudocoelomates:The body cavity is not completely lined with mesoderm. Instead,the mesoderm is present as scattered pouches in between the ectoderm and endoderm (Fig.4.3b). Such a body cavity is called pseudocoelom, e.g., in round-worms. Acoelomates :The animals in which the coelom is absent are called acoelomates, e.g., poriferans,coelenterates, ctenophores, and flatworms. In flatworms, the spaces between various organsare filled with special tissue called parenchyma

Coelomic body cavity : (a) coelom, (b) pseudocoelom and (c) acoelomSegmentation :-• In some animals, the body is externally and internally divided into segments with a serial

repetition of at least some organs.• For example, in earthworm, the body shows a pattern called metameric segmentation and

the phenomenon is known as metamerism.• Metameric segmentation is present in annelids only.

Notochord :-Notochord is a mesodermally derived rod-like structure formed on the dorsal side during embryonicdevelopment in some ani-mals. Animals with notochord are called chordates and animals whichdo not have this structure are called non-chordates, e.g., porifera to echinoderms.

Animal Kingdom


Phylum Protozoa (Unicellular Protists) :-• There are about 15,000 species of protozoans known to exist in the world.• They are microscopic heterotrophic organisms in which a single cell performs all the vital

activities. For this reason, protozoans are also referred to as acellular organisms.• They are aquatic (fresh water and marine) and cosmo-politan in distribution. Some forms

are predators and some parasitic.• The protozoan cell body is either naked, for example, Amoeba, or surrounded by a non-rigid

pellicle. Cel-lulose is absent in pellicle.• Some protozoans secrete shells of various inorganic compounds as external covers

(foraminiferans).• Different types of locomotory structures are found in protozoans. They may bear flagella

(flagellates), cilia (ciliates), or pseudopodia (sarcodines).• Locomotory structures are absent in the parasitic forms (sporozoa).• In protozoans, neurofibrils and contractile myofibrils are present underneath the cell surface.

Most protozo-ans are free-living and aquatic.• They are holozoic and feed largely on bacteria, micro-scopic algae, and minute animals such

as rotifers or on other protozoans including members of their own species.• Some protozoans are holophytic; they contain chlo-rophyll and prepare their own food by

photosynthe-sis (e.g., Euglena, Amoeba, Paramecium, Elphidium). The parasitic protozoansfeed on materials obtained from the hosts (e.g., Monocystis, Entamoeba, Plasmodium,Trypanosoma, Giardia, etc.).

Euglena• Contractile vacuole is found in almost all fresh-water protozoans for the maintenance of

osmotic concen-tration of cell body. This phenomenon is known as osmoregulation. Contractilevacuole also helps in ex-cretion.

• Many sporozoan parasites are relatively harmless, but some are harmful also. For instance,Plasmodium vivax and Plasmodium falciparum cause malaria in humans. Protozoans aregenerally uninucleate, but all ciliates and many amoeboid types are multinucleate.

• The pattern of reproduction is also specialized in dif-ferent protozoans. Most sarcodines,flagellates, and ciliates show asexual reproduction by binary fission, multiple fission, or evenbudding.

Animal Kingdom


• Some ciliates, for example, Paramecium reproduces by sexual means in which two individualscome close to each other and interchange genetic information by a process known as conjugation.

• There is no gamete formation in such a process. In sporozoa, some stages of life cycle showformation of gametes, which are morphologically distinct.

Classification of Phylum :-Protozoa Phylum protozoa is divided into four groups: Rhizopoda or Sar-codina, Mastigophoraor Flagellata, Sporozoa, and Ciliata.

Group 1 : Rhizopoda or Sarcodina :-The locomotion is by pseudopodia; body shape changeable, e.g., Amoeba (free-living),Entamoeba (parasitic or commen-sal), etc. Four types of pseudopodia are: lobopodia(Amoeba), filopodia (Euglypha), reticulopodia (Globigerina), and axopo-dia (Actinophryssol).

Group 2 : Mastigophora or Flagellata :-The locomotion by one or more thread-like flagella. They are free living or parasitic. Forexample,

Euglena : Connecting link between plants and animalsTrypanosoma : Parasite causing sleeping sicknessLeishmania : Parasite causing kala-azarGiardia : Parasite causing diarrheaTrichomonas : Parasite causing vaginitis in human fe-malsTrichonympha : Symbiont found in gut of termite help-ing in cellulose digestionProterospongia : Colonial with collar cells, a connecting link between Protozoa

and PoriferaTwo types of flagellates are phytomastigina (with chlo-roplast, plant-like, e.g., Euglena,Chlamydomonas, etc.) and zoomastigina (without chloroplast, animal-like, e.g., Trypano-soma, Leishmania, etc.).

Group III : Sporozoa :-All parasites have spore-like stage, no special locomotory orga-nelles, no contractile vacuole(associated with parasitism), and complex life history. For example,

Plasmodium : Causes malaria, spreaded by female AnophelesMonocystic : Parasite in the seminal vesicles of earthwormEimeria : Causes coccidiosis in rabbit and chickenBabesia : Causes hemoglobinuric fever/tick fe-ver in cattleBabesiais a protozoan parasite spread by ticks. In Inida, tick fever is caused mainly by

Babesis bigemina. The par-asite enters into red blood cells (RBCs) and destroys them.Group IV: Ciliata :-

Locomotory organelles are cilia; nuclei two or more in number.Examples are:

Paramecium : Free-living, slippery animalculeBalantidium : Causes balantidial dysentery in manNyctotherus : Rectal ciliate and endocommensal in frog

Animal Kingdom


PHYLUM PORIFERA :• Also called sponges.• Are usually marine and asymmetrical.• Have cellular level of organization.• Food gathering, respiratory exchange and removal of wastes occur through water canal

system.• Digestion intracellular.• Ostia (minute pores on body), spongocoel (body cavity) and osculum help in water transport.

They are lined by choanocytes (collar cells).• Body wall has spicules and spongin fibers.• Animals are hermaphrodite.• Fertilization internal.• Development is indirect, with larval stage which metamorphoses to adult. e.g., Sycon,

Euspongia.

Examples for Porifera : (a) Sycon (b) Euspongia (c) Spongilla

PHYLUM COELENTERATA:• Also called Cnidarians.• Are usually marine and radially symmetrical.• Sessile or free-swimming.• Have tissue level of organization• Diploblastic.• Presence of cnidoblast, for anchorage, defense and capture of prey.• Central body cavity called gastro-vascular cavity or coelenterone.• Digestion extracellular and intracellular.• Blind sac type body plan, with one opening called hypostome.• Body wall composed of calcium carbonate.• Exhibit two body forms: polyp and medusa e.g., Hydra, Aurelia.• Alternation of generation between body forms called Metagenesis occurs in Obelia where

Medusa sexually reproduced and polyp asexually reproduced. •e.g., Physalia, Adamsia.

Animal Kingdom


Examples of Coelenterata indicating outline of their body form :(a) Aurelia (Medusa) (b) Adamsia (Polyp)

Diagrammatic view of Cnidoblast

PHYLUM CTENOPHORA :• Also called as sea walnuts or comb jellies.• Are exclusively marine, radially symmetrical.• Have tissue level organisation, are diploblastic.• Digestion both extra and intracellular.• Body has eight external rows of ciliated comb plates for

locomotion.• Show Bioluminescence (living organism emit light). Example of Ctenophora

(Pleurobrachia)

Animal Kingdom


• Sexes are not separate i.e. hermaphrodite.• Reproduce only by sexual methods.• External fertilization.• Indirect developmente.g., Ctenoplana. Pleurobranchia.

PHYLUM PLATYHELMINTHES :• Also called as ‘flat worms’.• Have dorsoventrally flattened body.• Mostly endoparasites in animals

including human.• Bilaterally symmetrical,• Triploblastic• Acoelomate• Organ level organization.• Absorb nutrients through body surface.• Parasite forms have hooks and suckers.• ‘Flame cells’ help in osmoregulation and excretion.• Fertilization internal. Many larval stages.• Planaria has high regeneration capacity.

e.g., Taenia, Fasciola. Examples of Platyhelminthes :(a) Tape worm (b) Liver fluke

PHYLUM ASCHELMINTHES :• Also called ‘round worms’.• May be free living, parasitic, aquatic or terrestrial.• Are bilaterally symmetrical, triploblastic, Pseudocoelomates.• Alimentary canal complete (has muscular pharynx), wastes

removed through excretory pore. • Organ system level of organization.• Sexes separate i.e. dioecious.• Shows sexual dimorphism.• Females longer than males.• Fertilisation internal.• Development direct or indirect.

e.g., Ascaris, Wuchereria.

Aschelminthes – Roundworm

Animal Kingdom


PHYLUM ANNELIDA :• Are aquatic or terrestrial, free-living or parasitic.• Are bilaterally symmetrical, triploblastic,• Organ-system level of organization• Metamerically segmented body.• Have longitudinal and circular muscles in body wall for locomotion.• Aquatic annelid like Nereis has oar shaped parapodia for

movement. • Have nephridia for osmoregulation and excretion.• Nervous system consists of paired ganglia connected by lateral

nerves to a double ventral nerve cord.• Circulatory system is closed type.• Earthworm (Pheretima) and Leech (Hirudinaria) which are

hermaphrodites (i.e., monoecious).• Nereis an aquatic form is dioecious.• Fertilization is external• Development is direct or indirect.

Examples of Annelida :(a) Nereis (b) Hirudinaria

PHYLUM ARTHROPODA :• Largest phylum of Animalia includes insects.• Are bilaterally symmetrical, triploblastic and organ system level of organization, coelomate

and segmented body.• Body divisible into head, thorax, abdomen.• Body covered by a chitinous exoskeleton.• They have jointed appendages.• Respiration by gills, book gills, lungs or tracheal system.• Circulation is open type.• Excretion through malpighian tubules.• Sensory organs: Antennae, eyes; Organs of balance: Statocysts.• Mostly dioecious.• Fertilisation internal.• Are mostly oviparous.• Development is indirect or direct. e.g., Apis, Bombyx, Anopheles, Locusta, Limulus.

Examples of Arthropoda : (a) Locust (b) Butterfly (c) Scorpion (d) Prawn

Animal Kingdom


PHYLUM MOLLUSCA :• Second largest phylum of Animalia.• Terrestrial or aquatic.• Are bilaterally symmetrical, triploblastic and organ system level of organization, coelomate.• Body divisible into head, muscular foot and visceral hump and is covered by a soft and

spongy layer of skin called mantle.• Unsegmented body. • Body is covered by calcareous shell.• Respiration and excretion by feather like gills (ctenedium) in mantle cavity.• Head has sensory tentacles. Radula-file like rasping organ for feeding.• Usually dioecious, dioecious, have indirect development.

e.g., Pila, Pinctada, Octopus.

Examples of Mollusca : (a) Pila (b) Octopus

PHYLUM ECHINODERMATA :• Are spiny bodied organisms.• Endoskeleton of calcareous ossicles.• Are exclusively marine.• Radially symmetrical in adult but bilaterally symmetrical in larval stage.• Organ system level of organization.• Triploblastic and eucoelomate.• Digestive system complete. Mouth ventral, Anus on dorsal side.• Food gathering, respiration, locomotion carried out by water vascular system.• Excretory system is absent.• Dioecious i.e. sexes are separate.• Fertilization external. Development indirect (free swimming larva)

Animal Kingdom


Examples for Echinodermata : (a) Asterias (b) Ophiura

Phlum Hemichordata/Stomochordata :-Hemichordata was earlier considered as a sub-phylum under chordata. But now it is placedas a separate phylum under non-chordata.The phylum consists of a small group of worms-like marine animals with organ system levelof organization. Its character-istics are:

• In hemichordata or stomochordata, true notochord is absent.Gill slits are present but they are dorso lateral in position.They are worm like, bilaterally symmetri-cal, Triploblastic,and entero-coelomate animals.

• Stomochord is a hollow outgrowth arising from the roof ofthe buccal cavity, also called buccal diverticulum. It ispresent in the proboscis.

• Dorsal heart, ventral hollow nerve cord, and no res-piratorypigments. Circulatory system is open. Respi-ration occursby gills.

• Development is mostly indirect through a free-swim-mingtornaria larva, e.g.,Balanoglossus (acorn, tongue worm),Glossobalanus. Sexes are separate. Fertilization isexternal. Balanoglossus

• Excretory organ is proboscis gland.• Believed to be a connecting link between non-chor-dates and chordates.• The body is cylindrical and is composed of an anterior proboscis, a collar and a long trunk.• Due to the absence of true notochord in hemichordata, many taxonomists do not consider

these animals as chordates.• Examples: Balanoglossus,Saccoglossus

Animal Kingdom


Phlum Chorrdata :-

The most important characteristics of phylum Chordata are:

• Post anal tail.

• Closed circulatory system.

• Dorsal hollow nerve cord.

• Paired gill slits on the lateral sides of pharynx.

• They possess a notochord either throughout life or dur-ing early embryonic development.

Chordata Characteristics

Sub-Phylum Protochordata or Acraniata :-

Sub-Phylum 1: Urochordata :-

• The larva (Ascidian tadpole) undergoes retrogressive metamorphosis, i.e., change frombetter developed larva to less developed adult, e.g., Herdmania(sea squirt).

• This sub-phylum is also called Tunicata because the adult body is enclosed within a leathery

test or tunic formed of a cellulose-like organic substance termed tunicin.

• Vanadocytes are present except in Herdmania. Vanadium gives green color to blood. Excretionoccurs by neural gland, hence excretion is glandular.

• They are exclusively marine.

• Examples: Salpa, Doliolum, Ascidia.

Animal Kingdom


Phylum chordata can also be divided as:

Urochordata : (a) Salpa and (b) Ascidia

Animal Kingdom


Sub-Phylum 2: Cephalochordata :-• The notochord extends upto the anterior end of the body. Hence, this sub-phylum is named so.• The tail is present throughout life, e.g., Branchiostoma (Amphioxus).• Amphioxus/Branchiostoma has both ends pointed like lance. Hence, it is commonly called

lancelet.

Amphioxus

Sub-Phylum Vertebrata or Craniata :-• These are advanced chordates that have cranium (car-tilage or bony brain box) around brain.• Notochord is present only in the embryonic stages. It is replaced by cartilaginous or bony

vertebral column (back bone) in the adult forms. They have paired appendages as fins andlimbs.

• Closed circulatory system is present; muscular and ventral heart with two, three, or fourchambers; lymphatic system present; erythrocytes and hemoglobin are present.

• A pair of kidneys is present for excretion and os-moregulation; endocrine glands are welldeveloped; members are generally unisexual and have single pair of gonads.

Division 1: Agnatha (Jawless Vertebrates) :-• It includes two classes: Ostracodermi and Cyclostomata.• They are cold blooded.• Vertebral column is represented only by small imperfect neural arches over the notochord.• They do not have exoskeleton and paired appendages.• The mouth does not possess jaws, hence named Agnatha.• They are the most primitive of all craniates.• They have single nostril. Internal ear has one or two semicircular canals.

Class 1: Ostracodermi :-• They were the first jawless fishes (originated in Ordo-vician period in Palaeozoic era).• These were shell skinned with exoskeleton of bony plates, e.g., Cephalaspis.• Ostracoderms are all extinct now and are called fossil agnatha.

Animal Kingdom


Class 2: Cyclostomata: Its general characters are as follows :-• Circulation is of closed type.• Kidneys are mesonephric• Single sex organ discharges gametes in the well-devel-oped coelom.• Cranium and vertebral column are cartilaginous with persistent notochord.• Stomach is absent.• Cyclostomes have an elongated body bearing 6–15 pairs of gill slits in their gill pouch for

respiration and have a sucking and circular mouth.• A single dorsal nostril leads into closed nasal sac. A functional pineal eye is present just

behind it.• All living members of the class Cyclostomata are ectoparasites on some fishes. The body is

devoid of scales and paired fins. Head and brain are poorly developed. They are also calledjawless fishes.

Table : Difference between lamprey and hagfish

(a) Myxine (b) Petromyzon

Animal Kingdom


POINTS TO REMEMBER :-

1. Typhlosole is a fold of epithelium in the intestine. It prevents the rapid flow of food in theintestine and increases the absorptive surface area.

2. Ammocoete is the connecting link between Amphi-oxus and the cyclostomes.3. Larva ammocoetehatches out of eggs in about 14–21 days. The larval period may long from

three to seven years.4. Petromyzon, though marine, goes to fresh water for spawning, i.e., anadromous. After spawning

within a few days, they die.5. Lingual cartilage is also a part of skeleton, that lies in the tongue region and supports it

(lingual = related to tongue).

Division 2 : Gnathostomata (Jawed Vertebrates) :-• Embryonic notochord is usually replaced in adults by a vertebral column.• It includes advanced vertebrates.• Mouth has jaws, hence it is named gnathostomata.• Paired fins or limbs are present.• Internal ear has three semicircular canals. Girdles are present.• Gnathostomata is divided into two super classes: Pi-sces and Tetrapoda.• Paired nostrils are present.

Super Class 1—Pisces : Pisces includes true fishes. All are aquatic. The body bears fins. They arecold blooded. The char-acteristics are as follows:

• Neck absent, no upper or lower eyelids, no tympanum (only internal ear is present). Eacheye has a well-de-veloped nictitating membrane.

• Monocondylic skull; slimy glands present on skin.• Respiration occurs typically by gills.• Lateral line sense organs are present.• Both renal portal and hepatic portal systems are found. Hypophyseal portal system is also

present.• Scales are mesodermal or dermal and embedded in skin.• Vertebrae are amphicoelous type.• Heart two-chambered (S-shaped); venous heart with sinus venosus and conus arteriosus.• Kidneys are mesonephric, ammonotelic (sharks: ureo-telic).

Super class Pisces is divided into three classes: Placodermi, Chondrichthyes, and Osteichthyes.

Class I—Placodermi (extinct) : It includes the earliest fossil fishes which lived in fresh water.

Animal Kingdom


Body had an external protec-tive armor of bony scales or plates. Primitive jaws with teethwere present. Skeleton was bony. Fins were mostly formed of large spines, e.g.,Climatius(spiny shark).

• Autostylic jaw suspension; gill slits are covered by operculum.• The name placodermi means “armoured fish” or “plate skinned.”• Both paired and unpaired fins were present. Caudal fin heterocercal.• They appeared in Silurian period, flourished in Devo-nian and Carboniferous period, and

became extinct in Permian period.

Class II—Chondrichthyes: This class includes cartilaginous fish, e.g.,Scoliodon (dogfish),Torpedo (electric ray), etc. Sharks are fast-swimming predators, whereas the rays andskates are stout, bottom-living scavengers and mollusc feeders.

Scoliodon (dogfish)

Class III—Osteichthyes : It includes bony fishes, e.g.,Labeo, Hippocampus, Exocoetus, Catla,Clarias, Betta, Pterophyllum, etc.

Bony fishes : (a) Catla and (b) ExocoetusTable : Differences between cartilaginous and bony fishes

Animal Kingdom


Animal Kingdom


Some important fishes of super class Pisces

1. Torpedo (electric ray): Torpedo is bottom dwell-ing, carnivorous fish (Fig. 4.27). It stuns or kills theprey and enemies with electric shock from its electricorgans. The latter are modified muscles. The skin isscaleless.

Torpdo (electric only)

2. Pristis (sawfish):Head bears a series ofstrong tooth like denticles along the margin(Fig. 4.28). It uses these denticles foroffence and defence. It is viviparous.

Pristis (sawfish)

3. Exocoetus (flying fish):It does not fly but often leaps into the air upto about 6 m high. Thepectoral fins are modified into wing-like structures, with the help of which the fish glides .

Exocoetus (flysing fish)

4. Hippocampus (sea horse):The neck and head of the fish are horse like and the tail isprehensile. The male bears a brood pouch in which the female lays eggs and the latterremain there till they hatch.

Hippocampus (sea horse)

Animal Kingdom


5. Labeo (rohu): Labeo rohita and Labeo calbasu are the common fresh water edible carps.It is covered by large overlapping scales .

Labeo (rohu)

6. Clarias (cat fish/magur): Indian cat fish (Clarias ba-trachus) lives in ponds. It iscarnivorous. The head bears sensory threads called barbels. The body is smooth and withoutscales. Other fresh water cat fishes of India are Mystus seengala(slinghara), Rita lita, andWallago attu (Malli).

7. Latimeria chalumnae (coelacanth): Itwas first caught in 1938 off the east coastof South Africa. It swims by curious rotatingmovements of its pectoral fins. All its finsexcept the anterior dorsal are lobed. It isthe oldest living fish; and has survived tilltoday without under-going any change init. It is therefore described as a living fossil. Latimeria (coelacanth)

Some important body parts of super class PiscesFins

1. Paired pectoral and pelvic fins : Act as balancers and brakes; provide lift and counteractpitching and roll-ing.

2. Anterior dorsal fin : Counteracts rolling and yawing.3. Posterior dorsal and anal fins : Counteract yawing and rolling.4. Caudal fin : Propels the body and provides lift.

POINTS TO REMEMBER :-• Types of caudal fin

1. Diphycercal or protocercal : Most primitive kind of tail fin. The tail is symmetrical,both ex-ternally and internally as in protocercal, but it is secondarily symmetrical.

2. Heterocercal/hypocercal tail : Epicaudal and hypocaudal lobes are of unequal sizes.

Animal Kingdom


3. Homocercal : Identical lobes. Externally sym-metrical and internally asymmetrical.

Different type of coudal finas or tails in fishes

• Endothermic fishes : Although most fishes are ec-tothermic, a few species such as bluefish tuna and swordfish are able to maintain a body temperature higher than the temperatureof the water that sur-rounds them. Genetic studies of these endotherms have revealed thatthe ability to maintain high body temperature gives these fishes an adaptive advantage byallowing them to hunt in much colder waters than their competitors.

• Fish taken out of water dies of suffocation due to the lack of oxygen. This is because the gillfilaments stick together when taken out of water, thereby re-ducing the surface area.

• Freshwater species Marine species1. Catla catla (Catla/cat fish) 1. Sardinella (Salmon)2. Gyprinus carpio (Carp) 2. Hilsa (Hilsa)3. Labeo rohita (Rohu) 3. Harpodon (Bombayduck)4. Labeo calbasu (Calbasu) 4. Anguilla (Eel)• Some air-breathing fishes used their paired fins to move on land and gave rise to the first

land verte-brates. A living fossil of this group is Latimeria, a lobe-finned fish.Scales :-

1. Ganoid or rhomboid:Scales are thick, diamond- or rhomboid-shaped plates, e.g., primitivebony fishes such as Acipencer, etc.

2. Placoid:Backwardly directed spine arising from a ba-sal plate, e.g., Chondrichthyes (Fig.4.34).

Animal Kingdom


3. Cycloid:Thin, flexible, circular in outline, marked with concentric lines of growth which canbe used for determining age, e.g., lung fishes, Amia, etc.

4. Cosmoid:Absent in living fishes; consists of four dis-tinct layers: outermost ganoine, followedby cosmine, spongy bone, and innermost compact bone. Example,extinct fishes.

5. Ctenoid:Bear numerous small comb-like spines, e.g., higher bony fishes such as perch, etc

Different types of scales

Air bladder : It is associated with respiration, hydrostasis, sound production, and audition.Parental care

• Nest building, e.g., Gasterosteus, Amia (bow fin), Protopterus, Lepidosiren (nest is builtby the males of these fishes).

• Shelter in mouth, e.g., males of cat fish, Arius.• Brood pouch, e.g., male Hippocampus.

Table 4.9 Common food fishes of IndiaS.No. Fresh water food fishes Marine water food fishes1. Catla catla (Katla) Sardinella (salmon)2. Cirrhina mrigala(mrigal) Hilsa(hilsa)3. Mystus seenghala (singhara) Anguilla(eel)4. Labeo rohita (rohu) Stromateus(pomfret)5. Labeo calbasu (calbasu) Harpodon (Bombay duck)

Table 4.10 False fishes in Animal KingdomS.No. Common Name Genus Phylum1. Crayfish Astacus Arthropoda2. Devilfish Octopus Mollusca3. Starfish Asterias Echinodermata4. Hagfish Mysine Chordata

Animal Kingdom


5. Razorfish/Shellfish Solen Mollusca6. Jellyfish Aurelia Coelenterata7. Silverfish Lepisma Arthropoda8. Cuttlefish Sepia Mollusca9. Whalefish Balaenoptara Aquatic mammals

IMPORTANT POINTS :-1. Hilsa is the only Indian fish that migrates from sea to rivers for breeding.2. Most primitive fish (fossil) is Climatius (placodermi).3. Anabas (climbing perch). It has accessory respiratory organs for breathing atmospheric air

which enables the fish to take long overland excursions in search of earthworms.4. Pomfret is the most widely eaten fish in India.5. Stone fish is the most poisonous fish.6. Gambusia fish (larvivorous) was introduced into several tropical regions to control

malaria.

7. Catadromous fishes live in fresh water and godown to sea for breeding, e.g.,Anguilla(European eel). When fishes migrate fromrivers to sea, it is called catadromous migration.

Anguilla (European eel)8. Anadromous fishes live in sea water and move to rivers for breeding, e.g.,Hilsa,Salmon, etc.

When fishes migrate from sea to rivers, it is called anadro-mous migration.9. Dipnoi has incompletely divided three-chambered heart.

9. Urinary bladder is absent in fishes.10. Weberian ossicles were discovered by Waber (1820). These connect air bladder with internal

ear.11. Bioluminescent fishes: Anamalops,Porichthyes, etc.; sound-producing fishes: Mola,Batistes.12. The commercial name of integument of Scoliodon is “shagreen.”13. Typical trunk vertebrae of fish are amphicoelous, centrum peculiar as is supported by four

wedge-shaped calcified fibrocartilages forming a “Maltese cross” and leaving uncalcifiedarea.

14. The study of fish is called ichthyology.15. The study of skates, rays, and sharks is called torpedology.16. Some elasmobranchs retain urea in blood to maintian hypertonicity.17. Ampulla of Lorenzini is a thermoreceptor.18. Electric organs of electric ray are modified muscles.19. Poisonous glands are found in sting ray, eagle ray, Chimaera,Diodon, and Tetrodon.20. Fish byproducts are fish meals and fertilizers; fish flour, fish proteins, fish oil, steaming, fish

Animal Kingdom


glue, leather, artificial pearls, etc.21. Isinglass is a gelatinous product obtained from the air bladders of certain fishes such as

carps, salmons, cat fishes, etc. It is used for making cements, jellies, and for clarification ofwines and beers.

22. Crossopterygians (Rhipidistia, Osteolepisgenus) gave rise to amphibia.23. Parental care is well developed in Hippocampus.24. Types of vertebrae

Types of vertebrae based on the shape of centra in (sagital section)

Super Class 2—Tetrapoda: All gnathostomes excluding fishes are included in this super class.• They have lungs for aerial respiration. Their sensory organs are adapted for reception in air

such as vision, hearing, smelling, etc.• Typically all tetrapods (Gk. Tetra= four + podos = foot) possess two pairs of limbs.• Skin is adapted to withstand exposure to air.• Tetrapoda is divided into four classes: Amphibia, Rep-tilia, Aves, and Mammalia.

Class Amphibia : Vertebrates with dual-life (Gk. Amphi = two or both; bios = life). The generalcharacteristics of members of this class are as follows:

• Kidneys are mesonephric. Urinary bladder is present in frog. Larvae and tailed amphibians(e.g., salaman-ders) are ammonotelic. Frogs and toads are ureotelic.

• Ear consists of internal and middle ear. Tympanum (outer membrane) covers the middle ear.The middle ear has a single ear ossicle called columella auris.

• Ten pairs of cranial nerves are present. Sexes are sepa-rate; fertilization is external; oviparous;and develop-ment indirect.

• They return to water for breeding. Male lacks copula-tory organs. Indirect developmentoccurs. A fish-like stage, the tadpole, is present.

• The skin is smooth or rough, having cutaneous glands which keep it moist. They are usuallywithout scales, but if scales are present, they are hidden beneath the skin (e.g., Caecilians).

• Two pairs of limbs are used for locomotion.

Animal Kingdom


• The gills are present at least in the larval stage; some adult forms also carry them in additionto lungs (e.g., Necturus).

• Alimentary canal and urinary and reproductive tracts open into a common chamber calledcloaca which opens to the exterior.

• Skull is dicondylic, i.e., with two occipital condyles for articulation with vertebral column.• The respiratory organs are lungs, buccopharyngeal cavity, skin, and gills.• There are about 3000 species of amphibians out of which 2600 species are in the order

Anura.• They are present in the warmer regions of the world except newts and salamander, which

are present in cooler regions.• They occur only in fresh water and moist land. Am-phibians are not found in sea water.• They are poikilothermal animals. They are amphibi-ous in nature, i.e., they can live on land

as well as in water. They are mostly found in warm countries. They are ectothermic (coldblooded). Body is divisible into head and trunk. Tail may be present in some forms.

• The heart is three-chambered, having two auricles and one ventricle. In the heart, there arepresent sinus venosus and truncus arteriosus. Both hepatic portal and renal portal systemsare well developed.

• Male frog can croak louder than females because of the presence of vocal sacs.• Example: Bufo (toad), Rana (frog), Hyla (tree frog), Sala-mandra (salamander), Ichthyophis

(limbless amphibia).• Living amphibians are divided into three orders:

Animal Kingdom


Some amphibians belonging to the class Amiphibia

IMPORTANT POINTS :-1. Jaw suspension is autostylic; urostyle is the last com-ponent of vertebral column.2.The shape of second to seventh vertebrae is procoe-lous (typical); eighthvertebra: amphicoelous;

ninthvertebra: acoelous.3. Amphiuma has the largest RBCs among vertebrates.4. At the time of metamorphosis, tadpole does not feed.5. Blind worms (limbless amphibians) are unusual am-phibians as only one species lives in

water. All the other burrow underground and are rarely seen on the surface. Many do noteven need water to breed.

6. Word roots and originsa. Caudata: From Latin, Caudata meaning “tail.”b. Nictitating: From Latin, nictare meaning to “wink.”

7. Seymouria is a connecting link between amphibia and reptiles.8. Paedogenesis:Development of gonads and/or pro-duction of young ones by immature or

larval forms, e.g., salamander (Ambyostoma).9. Total neoteny is shown by Necturus,Siren, and Proteus.10. First toe is called hallux.11. Carboniferous period is known as the age of amphib-ians.12. The arrow poison frogs secrete a powerful poison from the skin which can cause instant

death.13. The most poisonous frog—Golden dart poison frog—is from South America. One adult frog

con-tains enough poison to kill 200 people.

Animal Kingdom


14. Toads are used in chinese medicines. The skin of toad secretes a substance that increasesthe blood pressure when injected into humans.

15. Some frogs have development in amazing ways to prevent their eggs from drying out. Thefemale su-rinam toad of South America carries her eggs in the pits/pockets of skin on herback. As many as 60 young ones pass through the tadpole stage while em-bedded in herback and then emerge as small frogs.

16. In frogs, external ears are absent, only tympanum is seen externally. Frogs have a tympanicmembrane on the surface of both sides of their head. The tympanic membrane of a humanare called eardrums and each is protected inside ear canal.

17. The skin of tadpole also secretes an enzyme, diastase.18. The upper jaw of frog is derived from quadrate carti-lage whereas the lower jaw is

derived from Meckel’s cartilage.Class Reptilia : Their name refers to their creeping or crawling mode of locomotion.

• Kidneys are metanephric. Excretion is uricotelic. Urinary bladder is absent in snakes andcrocodiles.

• Cranial nerves are in 12 pairs. Jacobson’s organ (vomeronasal organ) present in the roof ofbuccal cavity, concerned with smell, is well developed in snakes and lizards. They do nothave external ear openings. Tympanum represents ears.

• Sexes are separate. Males usually have a muscular copulatory organ. Fertilization is internal.Mostly are oviparous and development is direct. Some are viviparous. No metamorphosis.

• Reptiles are cold-blooded or poikilothermic animals.• There are only about 6000 species of reptiles now liv-ing. But fossils show that 200 million

years ago, the reptiles were the most dominant animals on earth.• Herpetology is the study of reptiles.• Mouth is terminal with conical teeth which are pleurodont in lizards and snakes and

thecodont in crocodiles. Teeth are absent and replaced by horny beaks in turtles.• Endoskeleton is bony; skull is monocondylic (with one occipital condyle).• Heart is usually three-chambered or partially four chambered. Interventricular septum is

incomplete. Heart is completely four chambered in crocodiles. Two systemic arches arepresent. Erythrocytes are oval and nucleated.

• The largest reptiles today are the “komodo dragon” Varanus komodoensis of Indonesia (alizard) 3 m in length, crocodiles (up to 7 m), pythons (up to 10 m), and giant tortoises weighingup to 600 kg.

• They are covered by dry and cornified skin having epi-dermal scales or scutes. Snakes andlizards shed their scales as “skin cast.” Scales prevent loss of body water and so reptiles donot require a moist environment like amphibians.

• Respiration is only through lungs, which is improved by the development of ribs.• Limbs when present are in two pairs; pentadactyl; digits have horny claws.

Animal Kingdom


(a) Chabeleon, (b) Crocodilus, (c) Chelone, and (d) Naja

• Examples: Chelone (turtle), Testudo (tortoise), Chameleon (tree lizard), Calotes (gardenlizard), Crocodilus (crocodile), Alligator(alligator),Hemidactylus (wall lizard),poisonous snakes—Naja (cobra),Bangarus (krait), Vipera (viper), etc.

• Classification of reptiles is based on the temporal fossa of skull. The class Reptilia is first

divided into five sub-classes: (1) Anapsida, (2) Euryapsida, (3) Parapsida, (4) Synapsida,

and(5) Diapsida.

• Out of the five sub-classes, the living reptiles are found only in two sub-classes: (1) Anapsida

and (2) Diapsida.

Animal Kingdom


1. Anapsida: Primitive reptiles with a solid skull roof. No temporal openings/fossae.Order : Chelonia• Commonly called turtles (marine), tortoise (terrestrial), and terrapins (edible

freshwa-ter).• Body encased in two shell plates, dorsal cara-pace, and ventral plastron.• Limbs clawed, webbed, or paddle-like.• Sternum is absent.• Jaws with horny sheath, no teeth.• Certain aquatic turtles perform cloacal res-piration, but all other reptiles re

spire with lungs.• Cloacal respiration is reported.

Table 4.11 Difference between tortoise and turtleTortoise Turtle

1. Forelimbs and hindimbs are not 1. Forelimbs and hindimbs aremodified into paddles. modified into paddles.

2. Head can be completely with drawn 2. Head is partially withdrawn into the shell.into the shell.

3. It has oval carapace. 3. It has heart-shaped carapace.4. It is usually larger in size. 4. It is comparatively smaller in size.5. It is semi-terrestrial and fresh 5. It is an aquatic and marine form.

water form.2. Diapsida

a. Order: Rhynchocephalia• Sphenodon is a protected animal under the law of New Zealand

government.• An interesting feature of Sphenodon is the presence of pineal or parietal

or third eye.• All are extinct except a living species Sphe-nodon punctatum.• Sphenodon is “Tuatara” of New Zealand. It is a living fossil and going to

become extinct.• Sphenodon is referred to as a living fossil because it has retained many

primitive characteristics of fossil or stem reptiles.b. Order : Squamata

• Serpentology or ophiology is the study of snakes.• Lizards have four well-developed pentadac-tyl limbs with claws. Example,

Calotes (gar-den lizard).• Divided into two sub-orders: Lacertilia (liz-ards) and Ophidia (snakes).• The glass snake Ophiosaurus derives its name from its ability to break off its

tail when seized.• Lizards are mostly comivorous, but a herhiv-orous lizard is lguana from South

and Central America.

Animal Kingdom


• Saurology is the study of lizards.• The tail of most lizards is easily broken off when threatened or seized by a

predator. This ability is known as autotomy. Autotomy is the voluntarybreaking of tail to confuse the enemy.

• Heloderma rarely bites humans, but its bite is fatal. Its poison is neurotoxic.• Limbs are absent in lizards such as Ophio-saurus, Anguls, and Rhineura,

also called glass snakes.• A limbless lizard can be distinguished from snakes by the presence of movable

eyelids and external ear opening.• Barkudia is a limbless lizard from South India.• A new tail is soon regenerated which, how-ever, does not possess vertebrae.• Most lizards are oviparous, two viviparous lizards are Phrynosoma (horned

toad) and Chameleon (tree lizard).• Draco is a lizard which glides with the help of patagium and hence called flying

dragon.• Heloderma (gila monster) is the only poison-ous lizard in the world. It is also

called “beaded lizard” because its scales resemble beads.• There are two species of heloderms, H. sus-pectum and H. horridum. Both

are found in America.• The largest living lizard in the world is the ferocious dragon, Varanus

komodoensis, found in Malaya Archipelago, Length is 2.5 m, weight over100 kg.

IMPORTANT POINTSSnake charming

• Raising its head and spreading its hood, the cobra gets ready to strike the moving flute tip.• The charmer knows the striking distance and adjusts himself so that the snake orients towards

the waving flute but keeps beyond the strike distance.• Contrary to general belief, the snake charmer’s cobra does not dance the tune of the flute.• Rather it follows the movement of the tip of the flute and the swaying body of its master,

who really moves with the rhythm of the music.Rattle snake muscles

• Most muscles would quickly tire from this kind of energetic activity, but the rattle snake canshake its tail for long periods of time.

• The muscle’s ability to use ATP in an efficient manner allows it to sustain a high level ofactivity.

• Rattle snakes have the quickest moving skeletal muscles in the animal world.• Their tail muscle allows them to shake their rattle 90 times each second.

Animal Kingdom


Identification of poisonous and non-poison-ous snake

Animal Kingdom


c. Order : CrocodiliaDifferences between crocodile, alligator, and Gavialis

(a) Crocodylus palustris (indiann freshwater crocodile),(b) Alligator missisiplensis (american alligat), and

(c) Gavialis gangeticu (gavial or gharial)

IMPORTANT POINTS• Many sea snakes are viviparous. Pit vipers are also mostly viviparous.• The oldest living animal in any Indian zoo is the Al-dabra giant tortoise.• Rattle snake’s tail emits a frightening sound which scares away the enemy.• The king cobra of India is the only snake in the world that builds a nest.• Benadryl is used as an antidote to counteract the effect of hemotoxins.• Seymouria is considered as the connecting link between amphibians and reptiles.• Mesozoic era is known as “age of reptiles.”• Loreal pit of pit viper is a thermoreceptor organ.• Reptiles without urinary bladder are snakes, croco-diles, and alligators.• Largest snake is python; smallest snake is thread snake.• Largest lizard is Komodo dragon; smallest lizard is two species of dwarf gecko.• Longest dinosaur is Diplodocus; smallest dinosaur is Compsognathus.• Ophiosaurus is known as “glass snake,” “blind worm,” or “slow worm,” limbless lizard.• Anguis is also known as blind worm and is limbless.• Most poisonous snake of the world is peninsular tiger snake.• Poisonous sea snake: Hydrophis• Heaviest dinosaur is Brontosaurus.• Largest living reptiles are (1) python, (2) crocodile, and (3) Komodo dragon.

Animal Kingdom


• Hemidactylus or wall lizard (gecko) is a swift run-ner on smooth vertical surface due to thepresence of vaccum pads.

• Draco is a flying lizard but it actually does not fly.• Heloderma is a poisonous lizard (gila monster).• Biggest flesh eater dinosaur is Tyrannosaurus• Horned dinosaur: Stegosaurus• Largest living carnivorous reptile is Crocodilus.• Thermomorpha is a group of reptiles which are con-sidered to be the ancestors of

mammals.• Hedonic glands present in males secrete a sticky sub-stance which hardens structures such

as spine and helps to hold the mate firmly.• In Uromastyx, cloaca possesses a pair of copulatory organs called hemipenes.• Russel’s viper is the largest Indian viper.• Hafkine Institute of Bombay is the main center where antivenom is produced.• Monitor lizard (Varanus) is the largest living lizard. Varanusis commonly called “Goye” or

“monitor”; semi-aquatic; slightly laterally compressed tail.• Carapace is hard shield like structure present on the dorsal surface of tortoise and turtle.• Reptiles arose in the lower carboniferous time, from labyrinthodont amphibia.• Phrynosoma is found in deserts; called “horned toad,” skin hygroscopic; takes water in the

form of dew; exudes red blood like stream from eyes, when-ever, terrified.• Iguana is 5–6 feet long; body and tail laterally com-pressed; arboreal in habit; herbivorous

found in trop-ical America.• Sphenodon is the only living genus of Rhynchoce-phalia. It is commonly called Tuatara. It

is found only in New Zealand. It is called a living fossil as it resembles with Hanaesaurus ofJurassic age.

• The limbs of Chameleon show syndactyly (fusion of digits) as an adaptation to arboreal lifeto form op-posable finger to hold the twigs.

Class Aves (birds) : The study of birds is known as ornithology.The general characters are as follows:

• Jaw bones are prolonged into a toothless beak or bill.• Oesophagus is dilated into a crop for quick feeding and storage. Crop secretes “pigeon milk”

during breeding season. Stomach is divided into a glandular proven-triculus and a musculargizzard. The junction of small intestine and rectum is marked by a pair of rectal cecae.Cloaca of birds is three-chambered: antenior copro-daeum, middle urodaeum and a largeposterior procto-daeum. There is no gall bladder in birds like pigeon.

• Limbs are two pairs. Forelimbs are modified as wings for flying. Hindlimbs or legs are large,each foot usu-ally bears four, clawed toes. Hindlimbs generally have scales.

• Birds are feathered bipeds, air breathing, truly flying vertebrates (other being bats from classMammalia).

Animal Kingdom


• Exoskeleton consists of feathers, scales, and claws, whichare epidermal derivatives. Skin without glands; the onlycutaneous gland is uropygial gland or preen gland/oil glandat the base of the tail.

• Respiration is due to compact, spongy, non-disten-siblelungs continuous with thin-walled air sacs. Air sacsreduce body weight, helps in double respiration andinternal cooling. Larynx is present without vocal cords.A sound box or syrinx producing voice lies at or near thejunction (furcula) of trachea and bronchi. Furcula

• Kidneys metanephric and three-lobed. Ureters open into cloaca. Urinary bladder is absent.Excretion is uricotelic.

• Heart is completely four-chambered as in mammals. Sinus venosus absent. Only right aortic(systemic) arch persists in the adults. The renal portal system is vestigial. Erythiocytes areminute, oval, and nucleated. The blood of the birds may be called the richest blood in theanimal kingdom. It has more RBCs per cubic mm of blood than in any other animal.

• Cranial nerves are of 12 pairs.• Olfactory organs are poor. Middle ear contains a single ossicle. Eyes possess nictitating

membrane. Pecten is a comb-like structure found in the eyes near blindspot. Pecten helps inthe nutrition of eyeball. Pecten is found in all birds except Kiwi.

• Sexes separate. Some birds show sexual dimorphism (e.g., parrot and peacock). Male birdhas a pair of ab-dominal testes and a pair of sperm ducts. A copula-tory organ is absent in allbirds except in ratitae, geese, ducks, etc. Females are oviparous with a single (left) functionalovary and oviduct (Mullerian duct). Devel-opment is direct.

• Different parts of oviduct secrete the following:Ostium—Dense albuminMagnum—White albuminUterus—Calcareous shell

• Birds are the first vertebrates to have warm blood. Body temperature is regulated(homoiothermous).

• Ala spuria (bastard wing): Feathers on first digit (thumb).• Eggs of birds are cleidoic (with calcareous shell), mac-rolecithal (amount of yolk), mesolecithal

(distribution of yolk). Extraembryonic membranes are present (amniota).

• Feathers are found only in birds. Feathers are made up of a protein keratin and are waterproof due to the oily secretion of preen glands. The arrangement of feathers on the body ofbirds is called pterylosis. The feather-less areas are called as apteria. Four types of feathersare: quill feathers, contour feathers, filoplumes, and down feathers. In the absence of downfeathers, the birds willnot be able to keep the body warm. Quill feathers in the wings are called remiges. Quillfeathers in the tail are called rectrices. Filoplumes and down feathers help in the insulationof the body.

Animal Kingdom


(a) Neophron, (b) Struthio, (c) Psittacula, and (d) Pavo• Example: Corvus (crow), Columba (pigeon), Psittacula (parrot), Struthio (ostrich), Pavo

(peacock), Aptenodytes (penguin), Neophron (vulture) (Fig. 4.41).

IMPORTANT POINTSTypes of feathers

1. Quills : They are large feathers found in wings and tail.• An umbilical groove extends all along the ven-tral side of rachis.• A small hole on the proximal end of calamus is known as inferior umbilicus; the hole

on the distal end of calamus is known as superior umbilicus.• Each vane is composed of parallel filaments, the barbs. Each bears barbules.• The distal barbules of each barb bear small hooklets.• It has a central axis called shaft.• Small proximal part of the shaft is hollow, trans-lucent, and cylindrical and is termed as

calamus.• The long-distal, solid, and opaque part of the stem is known as rachis.• Emu birds have an after shaft as long as the main shaft.

Kinds of feathers : (a, b) quill, (c) contour, (d) filoplume, (e) down, and (f) rictal bristle

Animal Kingdom


2. Coverts : They are small feathers found in thewings and tail. They fill up the gaps leftbetween the bases of the quills. They haveshort calamus in comparison to quills.

3. Contours : Small feathers that cover the bodyand give it its shape. They resemble the quills,but their barbs are not so strongly joined andcan be separated easily.

4. Filoplumes : Occur beneath contour feathers ;very small in size; consist of long rachis bearingat the tip a few weak free barbs with barbules.

5. Down feathers/nestling downs: They cover thenewly hatched bird. They consist of shortcalamus, reduced rachis bearing flexible barbswith short bar-bules. They are found beneathcontours. Fossil of Archaeopteryx

6. Bristles: Short calamus, a long rachis bearing a few vestigeal barbs at its base. Bristles occurneart the mouth in fly catchers. The first digit of the hand (thumb or pollex) bears a tuft ofsmall feathers known as bastard wing or ala spuria or false wing.

Classification of class Aves : Class Aves is divided into two sub-classes: Archaeornithes andNeornithes.

Animal Kingdom


Subclass I : Archaeornithes• All extinct Jurassic period birds of Mesozoic era.• Wings primitive with little power of flight.• Tail long, lizard-like with two lateral rows of rectrices.• Hand with clawed fingers.• Skull with teeth in both jaws, e.g., Archaeopteryx (Fig. 4.43).

Subclass II : Neornithes• Modern as well as extinct, post-Jurassic period birds.• Wings well-developed and adapted for flight (with few exceptions).• Tail short and reduced.• Teeth absent except in some fossil birds.• Sternum with keel or carina.• There are four super orders in this subclass:

1. Super-order I: OdontognathaeExample,Hesperornis (with teeth) is extinct.

2. Super-order II: Palaeognathae (Ratitae)Example, flightless running birds.

3. Super-order III: ImpennaeExample, penguins (Aptenodytes). Penguins are found in Antarctica (south pole).

They have paddle-like wings and cannot fly (Fig. 4.44). Penguins are marine and layeggs in ice.4. Super order IV: Neognathae (Carinatae)

Example, modern flying birds such as Columba (pigeon), Psittacula (parrot), Neophron(vulture), and Pavo (peacock).

IMPORTANT POINTSBrood parasite : Male Eudynamys (koel, kokila) sounds like kuoo-kuoo-kuoo. The femaleis generally heard during breeding season and has short and sharp call kik-kik-kik, otherwiseshe is mostly silent. It does not make any nest but lays eggs in crow’s nest. In this way, koelis a nestparasite. Male is black. Fe-male is brown and profusely spotted. The white Koel is known asthe Indian nightingalebecause of its pleasant sound.Eagle eyes : Eagles have much better vision than humans do. The birds keen eyesightallows it to see prey at great distances. Its visual acuity is three to four times higher than thatof humans.

Animal Kingdom


Differences between super orders Ratitae and Carinatae

Animal Kingdom


IMPORTANT POINTS• Fastest flying bird: Swift—rarely touches the earth.• Second largest bird is emu (Dromaeus) as is the most primitive living bird.• Recently extinct bird is Dodo(passenger birds) of Mauritius.• The incubation period of a hen’s egg at 102°F (38.8°C) is 21 days.• Though polygamy is common in birds, emu is strictly monogamous.• Penguins are flightless birds found in Antarctica; wings are paddle-like; act as flippers during

swim-ming; and are covered by scale-like feathers.• T.H. Huxley said “birds are glorified reptiles.” The feathers are highly modified reptilian

scales. Birds have scales on their legs. Their eggs resemble reptil-ian eggs in general buthave a calcareous shell.

• Largest bird: Struthio camelus—8 feet height, 300 lbs weight.• Smallest bird: Mellisuga helenae—5.5 cm long.• Smallest egg of bird: Mellisuga(humming bird).• The humming bird is the only bird which can fly backward as well as forward.• Largest egg of bird: Struthio—1.5-L capacity.• Largest sea bird: Diomedea epomorphora(royal al-batross); wing stretch 200–375 cm.• Deepest diver bird: Aptenodytes torsteri(emperor penguin)• Fastest swimmer bird: Pygoscelis papua(penguin)• Fastest runner bird: Struthio—60 km/h speed.• Heaviest bird of prey: Vulture gryphus.• Among the Indian birds, the sun birds are probably the smallest.• The bursa fabricii is a blind sac with much lymphoid tissue in the cloaca of some young birds.

It produces lymphocytes (a type of white blood corpuscles). It is also called “cloacal thymus.”• Indonesia has the most bird species facing extinction.• Red-billed Quelea(Quelea quelea) of Africa are the most abundant birds. Previously, the

house sparrow was considered the most abundant species of birds.• Jatinga is a village in Assam where a mass suicide of birds occurs.• The owl rotates its head through an angle of 270° as its eyes do not rotate in their sockets.

Each eye is fixed like a car headlight.• Copulatory organ (true penis) is present in ostrich, duck, swan, and goose.• Dr Salim Ali is a famous Indian ornithologist.• Columbia has the world’s richest diversity of birds.• Uropygium (tail): The projecting terminal portion of a bird’s body from which the tail feathers

arise.• Swifts use saliva for binding nest materials.• Kiwi lays the largest egg in proportion to its own size.• Himalayan bearded vulture is the largest Indian bird. Previously, the Sarus was considered

the largest In-dian bird.• Ostrich has the largest eyes of any land animal.• Kiwi is the only bird known to use the sense of smell for finding food on the ground.• The national bird of India is Pavo cristatus (peacock).

Animal Kingdom


Class Mammalia : They are terrestrial, warm-blooded (endo-thermous), or homeothermal animalsso that their body temper-ature remains constant inspite of the changes in the temperature ofthe environment.The general characters of this class are as follows:

• There is an external ear or pinnawith an external audi-tory meatus. This is in addition tomiddle and internal ear.

• In higher mammals, the anus is separated from the uri-nogenital aperture; consequently,urinary and genital ducts have no connection with the digestive tube.

• In males, testes have come to lie outside the body cav-ity in scrotal sacs (except in elephants,aquatic mam-mals, and prototherian mammals).

• Teeth are embedded in sockets of the jaw bone and are said to be thecodont. There are onlytwo sets of teeth in life time, one deciduous or milk set and another permanent set. Thiscondition is spoken of as diphyodont. There are four different types of teeth, hence mammalsare heterodont.

• The skin is covered with epidermal hair which acts as an insulating layer and allows highbody temperature to be maintained. The hair may be partly lost as a sec-ondary adaptation.In some aquatic mammals where hair is negligible, there is a subcutaneous layer of heatwhich provides insulation of heat and makes the warmblooded condition possible.

• Cerebral hemispheres and cerebellum are large-sized and highly developed with great increasein the cor-tex. The two cerebral hemispheres are joined by a transverse band of nerve fiberscalled corpus callosum. There are four solid optic lobes called corpora quadrigemina in themid-brain. Twelve pairs of cranial nerves are present.

• The middle ear has three ear ossicles called malleus, incus, and stapes; the internal ear hasa spirally coiled cochlea which acts as an efficient organ of hearing.

• The neck generally has seven cervical vertebrae.• The skin has two kinds of glands, sudorific glands which produce sweat; evaporation of

sweat controls the body temperature; second kind of glands is seba-ceous glands whichproduce an oily secretion which makes the hair water-resistant. Modified sweat glands(sudoriferous) form mammary glands which produce milk in females for the nourishment ofthe young for some time after birth. Because they possess mammae (breasts) and mammaryglands, they are called mam-mals. It is the most unique character of mammals.

• A muscular diaphragm divides the coelom into a tho-racic and an abdominal cavity; thethoracic cavity has a pericardial cavity containing the heart and two pleu-ral cavitiescontaining the lungs. The remaining vis-cera lie in the abdominal or peritoneal cavity.

• The heart is four-chambered with two auricles and two ventricles so that oxygenated bloodlies in the left half and deoxygenated blood in the right half. This condi-tion is also found inbirds. Only the left aortic arch is present. Erythrocytes are round, biconcave, and non-nucleated (except in camel where they are oval and non-nucleated).

• Examples : Oviparous—Ornithorhynchus (platypus); viviparous—Macropus (kangaroo),Pteropus (flying fox), Camelus (camel), Macaca (monkey), Rattus (Rat), Canis (Dog),Felis (cat), Elephas (elephant), Equus (horse), Delphinus(common dolphin), Balae-noptera(blue whale), Panthera tigris (tiger), Panthera leo (lion), etc.

Animal Kingdom


Difference between the three groups of mammals

(a) Ornithorhynchus, (b) Macropus, (c) Pteropus, and (d) Balaenoptera

Animal Kingdom


IMPORTANT POINTS• In humans, sweat glands are absent at lip borders, clit-oris, glans penis, nail beds, under

surface of prepuce.• Sweat or sudoriferous glands secrete sweat. Sweat comprises 95% water and 5% metabolic

waste.• Spiny ant eater, scaly ant eaters, moles, cetaceans, sirenians, and some edentates do not

possess sweat glands.• Tusks of elephants are two incisors of upper jaw which constantly grow throughout life.• Primates such as monkeys, man, apes, etc., acquired three-dimensional vision due to their

most evolved motor understanding of visual sensation.• Deer, amongst vertebrates, proportionately to their body size, possess largest eyes.• Carnassial teeth : Special shearing teeth in carni-vores for cracking bones—fourth premolar

of upper jaw and first molar of lower jaw.• Milk-producing male mammal: Spiny ant eater/Echidna.• Monotreme : With a single aperture of cloaca for uri-nogenital and digestive tracts.• Largest land animal: Loxodonta africana(African elephant), height 3.5 m and weight 7

tonnes.• Tallest land animal/mammal: Giraffe, up to 6 m.• Mouse and Rat have first molar bigger than com-bined second and third molars.• Stripes of no two zebras are alike.• Fastest mammal: Acinonyx jubatus(Cheetah) (extinct from India but present in Africa).

Speed up to 100 km/h.• Slowest terrestrial mammal: three-toed sloth (Brady-pus), Tridactylus, 100–150 m/h.• Slowest aquatic mammal: Sea otter, 10 km/h.• Longest gestation period in mammal: 609 days/20 months in Elephas maximus.• How many vertebrae do giraffes have in their neck ? Most of the vertebrates, including

giraffes and camel, have seven cervical (neck) vertebrae. At almost 6 m (20 ft) tall, thegiraffe is the tallest of all vertebrates and its seven cervical vertebrae are greatly elongated.Exception: three-toed sloth (Bradypus) with nine cer-vical vertebrae and Manatee is withsix neck vertebrae.

• Armadillos:The nine-banded armadillo (Dasypus) is one of the few mammalian species whoserange is expanding. In late 1800s, they lived only as far north as central Texas. Leprosybacteria is cultured in the armadillos (Dasypus).

• Humans remain plantigrade at rest or during locomo-tion; use only the toes for running.Thus, is called sub-plantigrade.

• The color of human skin is yellow to orange due to carotene pigment in the cells of stratumcorneum and subdermal fat cells. Melanin is found in melanocytes.

• Shortest gestation period in mammal: Opossum, 12–13 days.• Panthera tigris is the national animal of India (de-clared in 1973).• Today marsupials are found mainly in Australia ex-cept a few marsupials such as the American

opossum are found outside that continent.

Animal Kingdom


• Plantigrade mammals are those whose palm and sole touch the ground when moving fromone place to another, e.g., bears and certain insectivores (Fig. 4.46a).

• Whales, mice, shrews, and also some other mam-mals, but not rabbit and man, possesHarderian gland like that of frog.

• The scrotum of mammals contains testes in most of the mammals; it acts as a thermostaticchamber. Tes-tes lie outside the abdominal cavity because sperms cannot develop in bodytemperature. Thus, these be-come close, if the temperature falls more than 2°C or comeapart from the body, if temperature rises more than 2°C of the body temperature.

• In insectivores, chiroptera, and rodentia, scrotum is formed only during breeding season. Itlater moves to abdominal cavity, e.g., bat, otter.

• Rabbit is digitigrade because it moves on digits (Fig. 4.46b). feet of mammals• Unguligrade mammals are those whose only the tips of one or two fingers and toes remain

in contact with the ground both at rest and locomotion (Fig. 4.46c). These are fastest runningterrestrial mammals, e.g., horses, deers, cows, donkeys, etc.

• Hides are prepared from the dermis of animal skin.• Seals and whales have scanty hairs because heat in-sulation is done by blubber.• The horns of rhinoceros, scales of scaly ant-eater, and spines of porcupine are derivatives of

hairs.• The retina of owls contains only rods (suitable for noc turnal habit). Also, the same occurs in

shrews, hedge hog, rodents, bats, etc.• The retina of fowls contains only cones (suitable for diurnal habit). Squirrels also have only

cones.• Insectivores, edentates, proboscidians (elephants), cetaceans (whales) always have their

testes inside the body cavity.

Animal Kingdom


Non-Chordata

1. Sponges are most primitive multicellular organisms with which of the following levels oforganization?

(1) Acellular (2) Cellular

(3) Tissue (4) Organ system

2. Incomplete alimentary canal with blind sac type of body plan is present in

(1) Annelids (2) Arthropods (3) Platyhelminthes (4) Sponges

3. Select incorrect matching of animals, their body symme-try, and coelom.

S.No. Animals Symmetry Coelom

(1) Ctenophores Radial Acoelomate

(2) Platyhelminthes Bilateral Acoelomate

(3) Aschelminthes Bilateral Pseudocoelo-mate

(4) Annelids Radial Coelomate

4. Acoelomate diploblastic animal phylum is

(1) Platihelminthes (2) Cnidaria

(3) Aschelminthes (4) Hemichordata

5. Which of the following animal(s) has tube-within-tubetype of body plan evolved alongdeuterostomic evolutionary line?

(1) Annelids (2) Arthropods (3) Echinoderms (4) Molluscs

6. In the course of evolution, true coelom appeared for thefirst time in

(1) Annelida (2) Chordata(3) Aschelminthes (4) Echinodermata

7. Which of the following is incorrect matching of the phy-lum, their alimentary canal, andmetameric segmentation?

S.No. Phylum Alimentary Canal

Metameric Segmentation

(1) Annelida Complete Present

(2) Arthropoda Complete Present

(3) Mollusca Complete Absent

(4) Platyhelminthes Incomplete Present

8. Sponges in which the cells are loosely aggregated and do not form tissues or organs aregrouped under which subkingdom?

(1) Metazoa (2) Eumetazoa (3) Parazoa (4) Bilateria

EXERCISE

Animal Kingdom


9. The level of organization in coelentrates is

(1) Acellular (2) Cellular (3) Tissue (4) Organ system

10. Blind sac body plan is found in

(1) Sponges (2) Annelids

(3) Coelentrates (4) Round wonns

11. Annelids possess

(1) Cell aggregate plan (2) Blind sac plan

(3) Tube within a tube plan (4) Hollow sac plan

12. “Tube in a tube” plan is not exhibited by which one of the following phyla?

(1) Coelenterata (3) Annelida

(2) Aschelminthes (4) Arthropoda

13. An animal having triploblastic acoelomic condition is

(1) Ascaris (2) Periplaneta (3) Planaria (4) Sycon

14. Animals which are triploblastic with tube-within-tube type of body plan and embryonicblastopore forms anus (deuterostomia) are

(1) Annelids (2) Molluscs

(3) Platyhelminthes (4) Echinoderms

15. Echinoderms and chordates have

(1) Pseudocoel (2) Shizocoelom (3) Enterocoelom (4) Hemocoel

16. Body cavity of arthropods is called

(1) Coelom (2) Hemocoel

(3) Pseudocoel (4) Gastrovascular cavity

17. A deuterostomic animal is

(1) Star fish (2) Sea anemone (3) Pearl oyster (4) Octopus

18. True segmentation (metameric) occurred for the first time in

(1) Platyhelminthes (2) Aschelminthes (3) Annelids (4) Arthropods

19. Animals possessing pseudocoelom are

(1) Flatworms (2) Round worms (3) Annelids (4) Molluscs

20. True coelom appeared first in the course of evolution in

(1) Echinodermata (2) Annelida

(3) Chordata (4) Aschelminthes

21. The time period from the initial infection to the first ap-pearence of symptoms is known as

(1) Pre-patent period (2) Incubation period

(3) Pre-erythrocytic period (4) Exo-erythrocytic period

Animal Kingdom


22. Tetranucleated cyst stage is found in

(1) Entamoeba coli (2) Entamoeba histolytica

(3) Leishmania (4) Trypanosoma

23. Which of the following organisms is known to form ab-scesses in human liver, lungs, brain, etc. ?

(1) Entamoeba histolytica (2) Monocystis

(3) Plasmodium (4) Fasciola hepatica

24. Which one of the following constitutes the reserve food material in the cyst of Entamoebahistolytica ?

(1) Volutin granules (2) Starch granules

(3) Glycogen granules (4) Fat droplets

25. Slipper animalcule is the name of

(1) Pelomyxa (2) Actinophrys

(3) Euglena (4) Paramecium

26. Organelle concerned with offence and defence in Paramecium is

(1) Trichocyst (2) Radial canals (3) Kappa particles (4) Peristome

27. Conjugation in Paramecium is by

(1) Exchange of micronucleus (2) Exchange of macronucleus

(3) Exchange of + and – nuclei (4) Exchange of nuclei

28. The function of cytopyge in Paramecium is to

(1) Filter food particles

(2) Form the bolus of the food malerial

(3) Segregate debris from useful food material

(4) Egest the indigestible waste

29. Contractile vacuoles of Paramecium are analogous to

(1) Sweat glands of mammals

(2) Uriniferous tubules

(3) Gastrovascular cavity of Hydra

(4) Typhlosole of Earthworm

30. The removal of micronucleus in Paramecium will impair the function of

(1) Reproduction (2) Excretion (3) Osmoregulation (4) Locomotion

31. Locomotion in sporozoans occur by

(1) Flagella (2) Cilia

(3) Pseudopodia (4) Wriggling movement

Animal Kingdom


32. The most important characteristic of phylum Porifera is that the organisms

(1) Are acellular

(2) Possess blind sac type of body plan

(3) Possess canal system and choanocytes

(4) Possess water vascular system

33. Most of the sponges are marine and remain attached to rocks (sessile). The fresh watersponge is

(1) Sycon (2) Spongilla (3) Cliona (4) Euplectella

34. The path of water in a sponge is

(1) Dermal ostia Gastral ostia Osculum

(2) Dermal ostia Gastral ostia Spongocoel Oscu-lum

(3) Osculum Spongocoel Choanocytes Ostia

(4) Pinacocytes Choanocytes Enteron Osculum

35. The movement of water in syconoid type of canal system is

(1) Dermal ostia Canal Spongocoel Osculum

(2) Dermal ostia Incurrent canal Radial canal Spongocoel

Osculum

(3) Dermal ostia Incurrent canal Flagel-lated chamber

Excurrent canal Spongocoel Osculum

(4) Pinacocytes Choanocytes Enteron Osculum

36. Which one of the following cells is totipotent and respon-sible for regenerative capacity insponges?

(1) Pinacocytes (2) Thesocytes (3) Archaeocytes (4) Scleroblast

37. The skeleton of bath sponge, Euspongia, is made of

(1) Spongin fibers (2) Siliceous spicules

(3) Calcareous spicules (4) Spongin fibers and siliceous spicules

38. A sponge harmful to oyster industry is

(1) Spongilla (2) Euspongia (3) Hyalonema (4) Cliona

39. Which of the following lives in commensal relationship with shrimps and is called as Venusflower basket ?

(1) Leucosolenia (2) Euplectella (3) Euspongia (4) Sycon

40. The larva of Leucosolenia is

(1) Parenchymula (2) Amphiblastula (3) Planula (4) Trochophore

Animal Kingdom


41. The mode of digestion in sponges is

(1) Intracellular (2) Intercellular

(3) Intracellular and intercellular (4) None of these

42. The spongocoel of sponges is homologous to the

(1) True coelom of earthworm (2) Hemocoel of cockroach

(3) Pseudocoelom of Ascaris (4) None of these

43. In the absence of a closed vascular system, how do sponges manage to distribute thenutritive substances from choanocytes to rest of the cells ?

(1) Through cell-to-cell diffussion

(2) Through mesoglea which acts as the food reservoir and distribution system

(3) Through the wandering cells, amoebocytes

(4) Through cell-to-cell diffusion and amoebocytes

44. Hydra and Obelia are/have

(1) Diploblastic, blind sac body plan, radial symmetry, acoelomate

(2) Diploblastic, bilaterally symmetrical, acoelomate

(3) Triploblastic, radially symmetrical, coelomate

(4) Triploblastic, bilaterally symmetrical, coelomate

45. The most important characteristic of phylum Cnidaria is

(1) Cnidoblasts (2) Choanocytes

(3) Thesocytes (4) Archaeocytes

46. The digestion in Hydra is

(1) Extracellular (2) Intracellular

(3) Extracellular and intracellular (4) Holozoic

47. Metagenesis is found in

(1) Physalia (Portuguese man of war) (2) Hydra

(3) Obelia (4) Both (1) and (3)

48. Which of the following statement is incorrect about metagenesis?

(1) Alternation of asexual and sexual phases in the life cycle of Obelia is called metagenesis.

(2) Metagenesis is similar to alternation of generations as found in plants.

(3) Both the medusa and polyp are diploid.

(4) Medusa is the sexual phase and polyp is the asexual phase.

49. Jelly fish belongs to class

(1) Hydrozoa (2) Scyphozoa

(3) Anthozoa (4) None of these

Animal Kingdom


50. Sea anemone belongs to

(1) Anthozoa (2) Hydraozoa (3) Scyphozoa (4) Coelenterata

51. Which one of the following is a coelenterate ?

(1) Sea pen (2) Sea horse

(3) Sea urchin (4) Sea cucumber

52. Mark the incorrect match ?

(1) Obelia—Planula larva (2) Aurelia—Ephyra larva

(3) Nereis—Trochophore (4) Hydra—Hydrula larva

53. Hypnotoxin is produced by

(1) Penetrant (2) Volvent

(3) Large glutinant (4) Small glutinant

54. During the discharge of nematocyst, the function of lasso is to

(1) Press and squeeze out the thread tube

(2) Trigger the stimulus

(3) Prevent the detachment of nematocyst from nemato-blast

(4) None of these

55. A piece of Hydra will regenerate into a full Hydra if it contains a part of

(1) Epidermis

(2) Epidermis, gastrodermis, and interstitial cells

(3) Basal disc

(4) Epidermis, gastrodermis, and tentacles

56. Which one of the following (cell types) contains the sym-biotic Zoochlorellae in Hydra?

(1) Epithelio muscular cells of epidermis

(2) Endothelio muscular cells of gastrodermis

(3) Interstitial cells

(4) Algae embedded in the mesoglea

57. If the body stalk of Hydra is cut transversely into several segments, then in these frag-ments, tentacles would regenerate

(1) At the end that was close to the hypostome

(2) At the end that was close to the basal disc

(3) Randomly at either ends of the cut segments

(4) In none of the segments

Animal Kingdom


58. The main function of interstitial cells is

(1) Replacement of lost cells (2) Excretion

(3) Digestion (4) Defence

59. The organ pipe coral is

(1) Tubipora (2) Gorgonia (3) Pennatula (4) Meandrina

60. Which animal has been placed in wrong habitat ?

(1) Hydra vulgaris—sea water (2) Hydra gangetica—fresh water

(3) Obelia—sea water (4) Physalia—sea water

ANSWER-KEY

Que. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15Ans. 2 3 4 2 1 1 4 3 3 3 3 1 3 4 3Que. 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30Ans. 2 1 3 2 2 2 2 1 3 4 1 1 4 2 1Que. 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45Ans. 4 3 2 2 2 3 1 4 2 1 1 4 4 1 1Que. 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60Ans. 3 4 2 2 1 1 4 1 3 2 2 1 1 1 1

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4 ANIMAL KINGDOM - edukad.inedukad.in/wp-content/uploads/2018/01/pdfresizer.com-pdf-resize.pdf · Phylum Protozoa (Unicellular Protists) :-• There are about 15,000 species of protozoans