Class-9th BIOLOGY

STUDY NOTES & WORKSHEET

DIVERSITY IN LIVING ORGANISMS - II

Fig. 7.26: Classification of animals

DIVERSITY IN LIVING ORGANISMS- II

1. DETAILED CLASSIFICATION OF KINGDOM ANIMALIA

Animals are those organisms which are eukaryotic, multicellular and heterotrophic in their mode of nutrition. Animal cells do not have cell walls. Except a few, most animals are mobile. Multicellular animals are often called metazoa which have been divided into two branches : Parazoa and Eumetazoa. In Parazoa, the animal body is formed of loosely aggregated cells. These animals have poorly differentiated tissues and have no organ or digestive cavity. In Eumetazoa, the cells are properly arranged into tissues and organs. Their digestive tract is the mouth but with or without an anus. The Eumetazoa is further classified on the basis of :

(a) the number of germ layers present in the embryo; (b) the symmetry of the body of the organism; and (c) mode of origin of mouth.

Those animals which have two germ layers in the embryo, are called diploblastic animals and those having three germ layers are called triploblastic animals.

In diploblastic animals, the outer cell layer is called ectoderm, while the inner layer is termed as endoderm; Both of the germ layers enclose a non-cellular jelly-like layer, the mesoglea. The triploblastic animals have three germ layers, namely ectoderm, mesoderm and endoderm, in their bodies. (a) Diploblastic (b) Triploblastic

The two sides of the body are mirror images of one another. Such body symmetry type is called a bilateral symmetry. Some animals have radial body symmetry which can be defined as an arrangement of usually similar parts in a regular pattern around a central axis.

Bilateral symmetry Radial symmetry

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On the basis of mouth origin two types of animals have been recognised. Protostomia (mouth arising from or near the blastopore of gastrula; gastrula is an embryonic stage) and Deuterostomia (mouth arising anteriorly at some distance from the blastoprore).

Based on the presence or absence of body cavity or coelom. The acoelomates do not have a body cavity,

because in them the space between the body wall and digestive tract is filled with parenchymatous tissue.

The pseudocoelomates have a cavity between the body wall and digestive tract, but this cavity does not arise from the mesoderm and is not lined by epithelial cells.

The coelomates have a true body cavity or coelom which originates from the mesoderm and is lined by epithelial cells of mesodermal origin. Diagrammatic sectional view of :

(a) Coelomate (b) Pseudocoelomate (c) Acoelomate

1.1 Phylum Porifera (Organisms with holes, pore bearing)

Some common features of this phylum are : 1. These are non-motile animals attached to some solid support. They are

commonly called sponges. 2. Simplest multicellular, diploblastic animals. 3. The body design involves minimal differentiation and division into tissues. 4. Asymmetrical or radially symmetrical. Sponges may be vase-like, rounded,

sac-like or branched. 5. Body is perforated with numerous pores. The ostia, that open into a canal

system having canals and chambers lined with collared flagellated cells or choanocytes. It also has one or more large-sized outlets for water, called oscula.

6. Mouth, digestive cavity and anus absent. 7. Skeleton is made up of minute calcareous or silicious spicules or spongin

fibre (collagen) or both. 8. Reproduction is both asexual by budding and gemmules and sexual through

fertilization. Possess great power of regeneration.

Phylum Porifera is divided into the following three classes: Class 1. Calcarea. Marine. Examples: Leucosolenia, Sycon (Scypha) Class 2. Hexactinellida. Marine

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Example: Euplectella (Venus’s flower basket), Hyalonema (rope sponge) Class 3. Demospongiae. Mostly marine and a few fresh water solitary or colonial form. Examples: Cliona (boring sponge), Spongilla, Euspongia (bath sponge).

(a) Sycon (b) Euspongia (c) Spongilla (d) Euplectelea

1.2 Phylum Cnidaria or Coelenterata

Some common features of this phylum are : 1. Aquatic (living in water), mostly marine, a few such as Hydra are fresh water.

Some of these species live in colonies (corals, Physalia), while others live solitary (Hydra).

2. Cnidarians or coelenterates are multicellular, diploblastic animals with tissue grade of organisation. A gelatinous layer called mesoglea or mesohyl persists between the ectoderm (epidermis) and endoderm (gastrodermis).

3. Body shows radial symmetry. 4. A central gastrovascular cavity coelenteron is present which lacks anus but has

a mouth which is surrounded with short and slender tentacles. 5. Possess specialized sting cells (cnidoblasts) bearing stinging cell organelles

called nematocysts. Nematocysts serve the functions of paralysing the prey by injecting poison or holding the prey.

6. Respiratory, circulatory and excretory organs are absent. 7. Nervous system is primitive, has only network of nerve cells. 8. Exhibit the phenomenon of polymorphism (Gr., poly – many; morphe- shape)

which is the specialisation of individuals of colonial species for the division of labour. For example, hydrozoans have feeding individuals or zooids, the gastrozooids, protective zooids, the dactylozooids and reproductive zooids, the gonozooids producing sexual medusae.

9. Body shows two main forms, the polyps and the medusae. The polyp is diploid, cylindrical and sedentary. It is either solitary or colonial and reproduces asexually. The medusa is diploid, umbrella-like and free swimming sexual phase of the animal.

10. Asexual reproduction by budding and sexual reproduction by gametes formed by medusae.

11. Many forms possess a hard exoskeleton of lime to form corals.

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Phylum Coelenterata is divided into the following three classes. Class1. Hydrozoa. Their life history includes both polypoid and medusoid forms. Examples: Hydra, Obelia, Millepora (coral) Class 2. Scyphozoa. Their life history lacks polypoid phase and has only medusoid form. Examples: Aurelia (jelly-fish), Rhizostoma. Class 3. Anthozoa. Their life history has only polypoid form, the medusoid forms are absent. Example: Pennatula (sea-pen), Tubipora (organ pipe coral), Gorgonia (sea-fan), Corallium (red coral), Metridium (sea anemone), Fungia (mushroom coral).

(a) Aurelia (Medusa) (b) Adamsia (Polyp) (c) Hydra (d) Sea anemone

1.3 Phylum Ctenophora

Some common features of this phylum are : 1. Transparent body with bilateral symmetry.

Triploblastic. 2. Two tentacles and eight longitudinal rows of

ciliary comb-plates for locomotion are present. 3. Marine, solitary and free-swimming. 4. Nematocysts are absent but colloblasts

(adhesive cells) are present. 5. No polymorphism or dimorphism occurs. Examples: Pleurobrachia (comb jelly), Cestum (Venus’s girdle), Ctenoplana, Beroe (sea mitres). (Pleurobrachia)

1.4 Phylum Platyhelminthes

Some common features of this phylum are : 1. Bilaterally symmetrical (i.e., the left and right halves of the body have the

same design) and dorsoventrally flattended animals. 2. Body thin, soft, leaf-like or ribbon-like.

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3. They are triploblastic animals implying that their tissues differentiate from three embryonic germ layers. They are without a body cavity (acoelomate animals).

4. Digestive cavity (when present) with a single opening, the mouth (anus is absent).

5. Suckers and hooks are usually present. 6. Circulatory and respiratory systems and skeleton are absent. 7. Excretory system consists of blind tubules called protonephridia. Blind end

of a tubule bears a tuft of cilia or a flagellum and is called a flame bulb or flame cell.

8. Hermaphrodite, i.e., both male and female reproductive organs occur in the same individual.

9. The turbellarians are free-living, aquatic, both marine and fresh water and a few are terrestrial. Trematodes and cestodes are parasitic.

(a) Planaria (b) Liver fluke (c) Tape worm

Phylum Platyhelminthes includes the following three classes:

Class 1. Turbellaria –Dugesia, Planaria; Class 2. Trematoda – Fasciola (liver-fluke), Schistosoma (blood-fluke); Class 3. Cestoda – Taenia solium (pork tape-worm).

1.5 Phylum Nematoda (Aschelminthes)

Some common features of this phylum are : 1. Bilaterally symmetrical, triploblastic, pseudocoelomate and unsegmented

animals. 2. Body is worm-like (i.e., round, slender and tapering at the two ends),

cylindrical or flattened. 3. Body is covered with a tough, resistant cuticle; cilia absent. 4. Alimentary canal straight and complete with mouth and anus; pharynx

muscular. 5. Sexes are separate.

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6. Most forms are parasitic but some are free-living in soil or water.

7. Parasitic nematodes are pathogenic, meaning they produce diseases in the hosts. For example: elephantiasis.

Examples: Ascaris (round-worm), Ancylostoma (hook-worm), Wuchereria bancrofti (filarial worm), Enterobius (pinworm of human). Ascaris Wuchereria

Differences between Platyhelminthes and Nemathelminthes (= Nematoda)

Platyhelminthes Nemathelminthes 1. They are flatworms. 2. They are acoelomate. 3. They have an incomplete digestive system. 4. They are hermaphrodites (i.e., an

individual has both types of sex organs). Examples: Liver fluke, pork, tape-worm.

1. They are cylindrical in form and are called roundworms.

2. They are pseudocoelomate. 3. They have a complete digestive system. 4. They are unisexual (i.e., males and

females are present). Examples: Ascaris.

1.6 Phylum Annelida (Segmented worms)

Some common features of this phylum are : 1. Body triploblastic, bilaterally symmetrical, soft, elongated, vermiform and

cylindrical or dorsoventrally flattened. 2. Body is metamerically segmented externally by transverse grooves and

internally by septa. 3. Exoskeleton absent; body is covered by a thin cuticle. 4. Locomotory organs are segmentally arranged paired lateral appendages,

parapodia or chitinous setae or chaete. 5. Alimentary canal is tube-like, complete and extends straight from mouth to

anus. 6. True coelomate animals with closed blood vascular system. 7. Excretion by paired segmental nephridia which removes wastes from coelom

and blood stream directly to the exterior. 8. The nervous system consists of a dorsal “brain” and a ventral nerve cord

having ganglia and lateral nerves in each body segment. 9. Reproduction is by sexual means. Sexes may be united (hermaphroditic) or

separate. 10. They live in a variety of habitats. Mostly aquatic, marine or fresh water; some

are terrestrial (in moist soil), burrowing in tubes, some free-living forms.

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(a) Nereis (b) Earthworm (c) Leech (d) Hirudinaria

Phylum Annelida includes the following three classes: Class 1. Polychaeta Locomotion by segmetally arranged parapodia having numerous setae. Examples: Nereis (clam worm or sand worm),Aphrodite (sea mouse). Class 2. Oligochaeta. Body without distinct head and lack eyes, tentacles and parapodia. Examples: pheretima (earth worm), Eutypheus. Class 3. Hirudinea. Body with anterior and posterior suckers. Parapodia and setae are absent. Examples: Hirudinaria (Indian cattle leech).

1.7 Phylum Arthropoda (jointed foot animals)

Some common features of this phylum are : 1. Triploblastic, bilaterally symmetrical and metamerically segmented animals. 2. Body segments are grouped into two regions- cephalothorax (head and thorax

together) and abdomen, or three regions- head, thorax and abdomen. Anterior part of body forms a distinct head, bearing sense organs and brain.

3. Exoskeleton of cuticle, containing protein, lipid, chitin, and often calcium carbonate is secreted by underlying epidermis and shed (moulted) at intervals.

4. They have complex muscular system, with exoskeleton for attachment, striated muscles for rapid actions and smooth muscles for visceral organs. Cilia are absent.

5. Each body segment (somite) usually bears paired lateral and jointed legs or appendages.

6. Body cavity is haemocoel (i.e., filled with blood). The coeloms are reduced to the spaces of the genital and excretory organs.

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7. Alimentary canal is complete; mouth and anus lie at opposite ends of the body.

8. Respiration through general body surface, by gills, air tubes (tracheae) or book-lungs.

9. Circulatory system is open with dorsal heart, arteries and haemocoel (blood sinues) but without capillaries and veins. It means that blood does not flow in well-defined blood vessels.

10. True nephridia absent. Excretion by coelomoducts, malpighian tubules or green or coxal glands.

11. Sexes are usually separate; sexual dimorphism is well marked in several forms.

12. Fertilization is usually internal, oviparous or viviparous and often with metamorphosis.

13. Terrestrial or aquatic (fresh water and marine), free-living, commensal or parasitic (on other animals and plants) forms.

14. Arthropoda forms the largest phylum of Animal kingdom. About 900,000 species are known.

Phylum Arthropoda is divided into the following five classes:

Class 1. Onychophora. Body is elongated, segmented and is covered with thin cuticle. Example: Peripatus. Class 2. Crutacea. Head and Thorax are fused together to form cephalothorax. Respiration by gills. Examples: Palaemon (prawn), Daphnia (water flea), Cyclops (one- eyed gian), Cancer (True crab). Class 3. Myriapoda. Body is elongated, metamerically segmented with each segment having one or two pairs of legs. Respiration by tracheae. Examples: Scolopendra (centipede), Julus (millipede). Class 4. Insecta. Body is divisible into distinct head, thorax and abdomen. Abdomen lacks appendages, head has a pair of antennae and mouth parts and thorax has three pairs of legs and two pairs of wings. Respiration by tracheae. Examples: Lepisma (silver fish), Melanopus (grasshopper), Gryllus (house cricket), Periplaneta (cockroach), Musca (house fly), Apis (honey bee), Anopheles (mosquito), pieries (butterfly), cimex (bed bug). Class 5. Arachnida. Body divisible into cephalothorax and abdomen. Antennae and true jaws are absent.

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Respiration by tracheae, book-lungs or book-gills. Examples: Limulus (king-crab), Palamnaeus (scorpion); Sarcoptes (itch-mites), Aranea (spider) , Argus (tick).

(a) Locust (b) Butterfly (c) Scorpion (d) Prawn

Differences between annelids and arthropods

Annelids Arthropods 1. Their appendages are unjointed. 2. They have a closed circulatory

system, i.e., their blood flows inside blood vessels.

3. They have a well developed true coelom.

4. A chitinous exoskeleton is absent in

them. 5. Their excretory organs are nephridia.

6. Their sensory system is less

developed. 7. Their locomotory organs include

parapodia and chaetae. Examples. Earthworm, Nerreis.

1. Their appendages are jointed. 2. They have a open circulatory system,

i.e., their blood flows through large sinuses or spaces.

3. They have a small coelom. Instead they have blood filled body cavities called haemocoel.

4. A chitinous exoskeleton is present in them.

5. Their excretory organs are green glands and malpighian tubules.

6. Their sensory system is well developed.

7. Their locomotory organs are legs and wings.

Examples. Centipede, crab, cockroach.

1.8 Phylum Mollusca (molluscus-soft)

Some common features of this phylum are : 1. Body is soft, bilaterally symmetrical, with little segmentation and without

appendages. 2. Body is divisible into an anterior head, a ventral muscular foot, a hard dorsal

visceral mass. The entire body is covered by a fold of thin skin, called mantle which secretes a hard calcareous shell.

3. Body cavity is haemocoel. 4. Digestive tract has a simple structure. 5. Respiration through gills (called ctenidia), mantle or a “lung” of the mantle. 6. Circulatory system is open except in cephalopods.

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7. Excretion by a pair of metanephridia or kidneys. 8. Sexes are usually separate. 9. Sensory organs of touch, smell, taste, equilibrium and vision. 10. Aquatic, mostly marine, few fresh water and some terrestrial forms.

Osmoregulatory organs are closed at the inner end, they are called protonephridia, but when they open into a coelomic space at their inner end, they are called metanephridia.

(a) Chiton (b) Octopus (c) Pila (d) Unio

The phylum Mollusca is divided into the following five main classes:

Class 1. Polyplacophora. Shell composed of eight calcareous pieces. Example: Chiton Class 2. Gastropoda. Univalve shell and visceral mass are spirally coiled (torsion). Examples: pila (apple snail), Aplysia (sea hare), Helix (garden snail), Limax (gray slug). Class 3. Scaphopoda. Tusk-like tubular shell opens at both ends. Examples: Dentalium (tusk shell) Class 4. Pelecypoda (Bivalvia). Shell consists of two lateral valves hinged together mid-dorsally. Examples: Unio (fresh water mussel), Mytilus (sea mussel); Pinctada (Indian pearl oyster), Teredo (ship worm). Class 5. Cephalopoda. Shell external, internal or absent. Foot altered into a series of sucker-bearing arms or tentacles. Eyes are highly developed. Examples: Nautilus, Loligo (squid), Sepia (cuttle-fish), Octopus (devil-fish)

1.9 Phylum Echinodermata (spiny skin)

Some common features of this phylum are :

1. Simple animals may be star-like, spherical or elongate. 2. Body triploblastic, coelomate, unsegmented (nonmetameric) and radially

symmetrical (larva bilaterally symmetrical). i.e., pentamerous symmetry in adults.

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3. Body lacks head, but has oral and aboral surfaces. Oral surface of body has five radial areas called ambulacra.

4. Body wall is covered with spiny hard calcareous (calcium carbonate) plates (ossicles) that forms a rigid or flexible endoskeleton.

5. Body cavity is modified into a unique water vascular system which moves respiratory and locomotary organs, the tube feet or podia.

6. Digestive system is usually complete. Anus is absent in ophiuroids. 7. Excretory organs absent. 8. Reproduction sexual, asexual or by regeneration. Sexes are separate. 9. Exclusively marine, free-living and gregarious (live in groups) animals.

(a) Antedon (b) Holothuria (c) Echinus (d) Asterias (feather star) (sea cucumber) (sea urchin) (star fish)

Phylum Echinodermata includes the following five classes:

Class 1. Crinoidea. The oral surface is directed upward. Example: Antedon (feather star) Class 2. Holothuroidea. Worm-like body without arms and spines. Mouth surrounded by tentacles. Example: Holothuria, Cucumaria (sea cucumber) Class 3. Echinoidea. Spherical or discoidal body lacking arms. Body enclosed in an endoskeletal shell. Examples: Echinus (sea urchin) Class 4. Asteroidea. Flattened, pentagonal or star-shaped body with flexible endoskeleton. Examples:Pentaceros (sea pentagon), Asterias (star fish or sea star) Class 5. Ophiuroidea. Asteroids-like body is flat and composed of long arms and a central disc. Examples: Ophioderma (brittle star), Ophiura (brittle star).

1.10 Phylum Hemichordata (hemi = half)

Some common features of this phylum are : 1. Body is soft, unsegmented worm-like and bilaterally symmetrical. These

animals possess a combination of invertebrate (nonchordate) and chordate characters.

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2. Body is divided into proboscis, collar (collarette) and trunk.

3. These animals resemble chordates only in having pharyngeal gill-clefts or gill slits. Gill slits form the respiratory system and connects the pharynx with outside.

4. ‘Buccal diverticulum’, earlier regarded as “notochord” is present in proboscis.

5. No nephridia. Single glomerulus connected to blood vessels has a excretory function.

6. Exclusively marine, solitary or colonial, mostly tubicolous and detritus feeders like the earthworms. Balanoglossus

Examples: Balanoglossus (acorn worm or tongue worm;), Cephalodiscus.

Differences between non-chordates and chordates

Nonchordates Chordates 1. Notochord is absent in them. 2. Their central nervous system is

solid and ventral. 3. Heart, if present in them, is dorsal in

position. 4. Their circulatory system is of open

or closed type. 5. Respiratory pigment, the

haemoglobin, if present, is dissolved in plasma of blood.

6. Pharyngeal gill slits are absent in them.

7. They contain anus at posterior end of body, so post-anal tail is not present.

1. Notochord is present in them at some of their developmental stage.

2. Their central nervous system is hollow and dorsal.

3. Heart is always present and it is ventral in position.

4. Their circulatory system is of closed type.

5. Haemoglobin is present in their red blood cells or corpuscles.

6. Pharyngeal gill-slits are present in

them. 7. Their anus is not located at

posterior tip of body, so contain a post-anal tail.

1.11 Phylum Chordata (chorda = string)

Some common features of this phylum are : 1. Chordates are characterized by the following three features: (a) a dorsal,

hollow, tubular nerve cord; (b) a pliable rod called notochord that occurs ventral to nerve cord and is replaced by a bone or cartilage to form a vertebral column in vertebrates; and (c) paired gill-slits in the pharynx.

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The notochord is a long rod-like support structure that runs along the back of an animal and separates the nervous tissue from the gut. Notochord is a primitive type of endoskeleton which is characteristic among all chordates, at some stage of life cycle. The notochord provides longitudinal stiffening of the main body axis, a base for trunk muscles and an axis around which the vertebral column develops.

2. Body bilaterally symmetrically, metamerically segmented, triploblastic and coelomate.

3. A post-anal tail present at some stage of life. 4. Segmental muscles in an unsegmented trunk. 5. Ventral heart, with dorsal and ventral blood vessels and closed blood vascular

system. 6. Complete digestive system. 7. A cartilaginous or bony endoskeleton present in majority of members

(Vertebrates).

Chordata characteristics Chordata is the most advanced group of animals. Phylum Chordata is

divided into two groups: Protochordata (Acrania) and Vertebrata (Craniata).

Protochordata includes two subphyla, Urochordata and Cephalochordata. Group Vertebrata is divided into two subphyla, Agnatha and

Gnathostomata. Agnatha includes a single class Cyclostomata. Gnathostomata is divided into six classes: Chondrichthyes, Osteichthyes,

Amphibia, Reptilia, Aves and Mammalia. Chondrichthyes and Osteichthyes, both are commonly known as (fishes).

A. Protochordata

Subphylum 1. Urochordata (Gr., oura-tail), or Tunicata.

They are bag-like, sessile, soft-bodied, non-metameric animals. Adult body is covered with a tunic or test containing cellulose. Notochord is present only in the tail of free-living tadpole-like

larva. Sessile adult has no notochord. Dorsal tubular nerve cord is present in the larval form and it

degenerates in the form of small ganglion in the adult.

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The only chordate character present in the adult animal is the presence of numerous gill-slits in the pharynx.

Hermaphrodites. Exclusively marine, solitary and colonial.

Examples: Oikopleura, Herdmania, Pyrosoma, Doliolum, Salpa.

Subphylum 2. Cephalochordata

Fish-like, metamerically segmented, headless coelomate animals which retain notochord, dorsal tubular nerve cord and pharyngeal gill-slits throughout life.

Notochord and nerve cord extend throughout the entire length of body.

Exoskeleton, head, jaws and paired fins are absent. Pharynx large and perforated by numerous gill-slits. Sexes separate. Marine, burrow in the sand of shallow sea water.

Examples: Amphioxus or Branchiostoma (lancelet). B. Vertebrata

Subphylum 1. Agnatha (Gr., a – without; gnathos – jaws).

Animals have vertebral column and cranium. Without true jaws; but possess a suctorial mouth. Without paired appendages or fins.

Agnatha includes the following single class:

Class – Cyclostomata (circular mouth)

Body is long, elongated and eel-like. Skin is soft, slimy, smooth and scaleless. Mouth is round, suctorial and without jaws. They are ectoparasites

and use their mouth to stick to the back of other fishes. Single and median nostril is present. Respiration is through gills contained in pouches. Endoskeleton is cartilaginous and the notochord is in the form of

cylindrical rod and persists throughout life. Heart is two chambered. Gonad is single and fertilization is external. Development is direct

or indirect. Petromyzon has ammocoete larva in its life cycle. Aquatic, marine and fresh water. Free-living and ectoparasites of fishes.

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Examples: Petromyzon (lamprey), Myxine (hagfish), Bdellostoma (hagfish)

Subphylum 2. Gnathostomata (jaws and mouth): Vertebrates with jaws and paired appendages. This subphylum is divided into the following six classes:

Class 1 and Class 2 (Chondrichthyes and Osteichthyes) are combined to form super class - Pisces

Class 1. Chondrichthyes (Cartilaginous fish)

Marine fishes with completely cartilaginous endoskeleton. They are generally large in size (up to 10 – 20 metres long).

Streamlined body is either laterally compressed and spindle-shaped or dorsoventrally flattened and disc shaped.

Mouth is ventral in position. Skin is tough and covered with minute placoid scales. Respiration through gills. The gill-slits are not covered by gill-cover or

operculum. They have fins for locomotion (swimming) and balance. Fins may be paired

(pectoral fins, pelvic fins) or median (dorsal fin, caudal fin and anal fin). Tail or caudal fin is heterocercal. Muscular tail is used for movement. Heart is two chambered. Digestive system has a J-shaped stomach. Sense of smell, vibration reception and electro-reception developed. Alimentary canal and urinogenital ducts open into a common aperture, called

cloaca. Excrete urea (ureotelic animals).

Synchiropus splendidus Caulophyryne jordani Pterois volitans Electric ray (Mandarin fish) (Angler fish) (Lion fish) (Torpedo)

Sting ray Scoliodon (Dog fish) Pristis

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Examples: Scoliodon (dog-fish, Indian shark), Sphyrna (hammer-headed shark), Torpedo (electric ray), Trygon (sting ray), Pristis (saw-fish).

Class 2. Osteichthyes (Bony fishes)

Marine and fresh-water fishes with partly or whole bony endoskeleton. Size varies from 10 mm to 4 metres. Body is generally spindle-shaped. Skin is either naked or covered with cycloid or ctenoid scales. Mouth is usually terminal (anterior) in position. Four pairs of gills are present and they are covered by operculum. Gills

are filamentous. Fish obtain oxygen dissolved in water by using gills. Tail or caudal fin is homocercal. Cloaca is absent. Anus and urinogenital apertures are distinct. Excrete ammonia (ammonotelic animals). Heart is two chambered containing one auricle and one ventricle. They are cold-blooded (ecothermic) animals. They lay eggs and fertilization is external.

Examples: Labeo (rohu, carp), Pterois volitans (lion fish), Hippocampus (sea horse), Anabas(climbing perch).

Labeo rohita Male Hippocampus Exocoetus Anabas (Rohu) (Sea horse) (Flying fish) (Climbing perch)

Differences between bony fishes and cartilaginous fishes

Bony fishes Cartilaginous fishes 1. They have a bony endoskeleton. 2. They contain four pairs of gill slits. 3. Their gill slits are covered with an

operculum. 4. Their mouth is terminal in position. 5. Their caudal fin is homocercal. 6. Air bladder is usually present in them. Example. Carp, sea horse, etc.

1. They have a cartilaginous endoskeleton.

2. They contain 5-7 pairs of gill slits. 3. An operculum is absent in them. 4. Their mouth is ventral in position. 5. Their caudal fin is heterocercal. 6. Swim bladder is absent in them. Example. Indian shark, electric ray, etc.

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Class 3. Amphibia. It includes frogs, toads, newts and salamanders.

In evolutionary terms, amphibians form the first group among the chordates to live outside water.

These animals live partly in fresh water and partly on land (moist places).

Skin is smooth or rough, moist, slimy, glandular and mostly without scales. Skin has mucus glands.

Body has a distinct head and trunk and has no neck. Mouth is usually large.

Two pairs of pentadactyl (five digit) limbs are present. Digits or toes are without claws. Limbs may be absent in some cases.

Three-chambered heart has two auricles and one ventricle. Double circulation through the heart.

Respiration either by gills, lungs, skin or the mouth lining. Excrete either ammonia (tadpole larva) or urea. Oviparous, lay yolk-laden eggs with gelatinous covering usually in

water. Fertilization is external in frogs and toads, but internal in salamanders and apoda. Metamorphosis is present.

Ectothermal (= cold blooded animals).

Salamandra Toad Rana tigrina Hyla (Common frog) (Tree frog)

Examples: 1. Apoda: Ichthyophis; 2. Urodela: Amphiuma, Salamandra, Ambystoma, Necturus; 3. Anura: Rana (bull frog), Bufo (toad), Hyla (tree-frog).

Class 4. Reptilia (to crawl; creeping vertebrates) includes lizards, snakes, crocodiles and tortoises.

Ectothermic or cold-blooded, terrestrial or aquatic vertebrates with a body covered with dry water-proof skin having horny epidermal scales or dermal scute plates.

Body varies in form and is usually divided into head, neck, trunk and tail.

Limbs are tetrapodous pentadacytle (five-toed) type, with clawed digits (limbs are absent in snakes and some lizards).

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Tympanum is small and depressed. Teeth are present in all reptiles except in tortoises and turtles. Respiration is through lungs only. No gills are present. Heart is three chambered and is divided into two auricles and an

incompletely divided ventricle. Only crocodiles have four-chambered heart.

Terrestrial reptiles such as snakes and lizards excrete uric acid (uricotelic animals).

Fertilization is internal. Most reptiles are oviparous and lay their eggs with tough covering

and do not need to lay their eggs in water. A few reptiles are viviparous (e.g., lizards and snakes). No aquatic larval stage.

Chameleon Crocodilus Chelone Naja Flying lizard House wall lizard (Draco) (Hemidactylus)

Examples: Testudo (land-tortoise), Calotes (garden-lizard), Python(ajgar), Naja (cobra), Crocodilus(muggar), Gavialis (gharial).

Differences between Amphibia and Reptilia

Amphibia Reptilia 1. Their skin is glandular, smooth and

moist 2. Scales are not present in them. 3. Their digits do not possess claws. 4. They have a three-chambered heart. 5. Fertilization is external. 6. Extra-embryonic membranes (e.g.,

amnion, allantois, chorion) are absent. 7. Their eggs have a soft covering. Example, Frog, toad

1. Their skin is non-glandular, dry and keratinised.

2. Horny scales are present over their body surface.

3. Their digits end in claws. 4. Their heart is incompletely four chambered. 5. Fertilization is internal. 6. Extra-embryonic membranes are present in them. 7. Their eggs have a hard covering or shell. Example. Lizard, snake, tortoise, dinosaurs (extinct)

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Class 5. Aves (Birds)

Warm-blooded, tetrapodous vertebrates with various flight adaptations.

Size ranges from smallest humming bird to largest ostrich. Horny scales persist on the feet but feathers cover most of the body

Cutaneous glands are absent. Spindle-or boat-shaped body is divisible into head, neck, trunk and

tail. Fore-limbs modified into wings for flight. Kiwis have vestigial

wings. Hind-limbs bear four clawed digits and are adapted for walking,

perching, or swimming. Narrow jaws form a horny beak, which is modified for different

purpose. Teeth are absent. Bones of endoskeleton are light and spongy due to the presence of

air cavities. They breathe through lungs. Four-chambered heart with two auricles and two ventricles. Cloaca is present. Excrete semisolid urine having uric acid (uricotelic animals). No

bladder. Birds have highly developed voice, hearing and vision. They also

have specialised sense for nest building and care for the young (parental care).

Fertilization is internal. They are oviparous and lay large, yolk-laden eggs having hard shell.

Neophron Struthio Psittacula Pavo White Stork Ostrich Male Tufted Duck (Ciconia ciconia) (Struthio camelus) (Aythya fuligula)

Examples: Passer (house sparrow), Corvus (crow), Columba (pigeon), Psittacula (parrot), Bubo (owl), Milvus (kite), Gypus (vulture).

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Class 6. Mammalia

Mammals are warm-blooded and the most evolved animals of Animal Kingdom.

Hairs and the subcutaneous fat form an insulating layer. Cutaneous glands such as sweat glands, scent glands and sebaceous (oil) glands are present.

Body is divisible into head, neck, trunk and tail. Movable eyelids are present.

Females have milk-producing mammary glands which secrete milk for the nourishment of the young.

Fleshy external ear (pinnae) present. Middle ear with three ossicles. Teeth are thecodont (embedded in sockets in the jaws) and are heterodont

(differentiated into incisors, canines, premolars and molars). Two pairs of pentadactyl limbs are present. Digits in the fore-limbs and

hind-limbs are never more than five and end in claws, nails or hoofs. A muscular diaphragm separates thoracic and abdominal cavities. Respiration is through lungs only. Heart is four-chambered. Nonnucleated biconcave red blood corpuscles are

present. Excrete urea (ureotelic animals). Penis is always present. Fertilization is internal. Most mammals familiar to us, produce live young i.e., they are viviparous. Parental care is highly developed. Mammals live in all kinds of habitats. They are primarily terrestrial

animals.

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

Examples: Macropus (kangaroo), Panthera (lion, tiger, leopard), Canis (dog), Camelus (camel), Rhinoceros, Elephas (elephant), Ursus (bear), Macaca (monkey), Homo (human being).

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Differences between Aves and Mammalia

Aves Mammalia 1. Forelimbs are modified into wings. 2. The body is covered with feathers and

scales. 3. Skin is dry only a single preen gland

is present. 4. Mammary glands are absent. 5. A diaphragm is absent. 6. A toothless beak is present. 7. Bones of birds are hollow or

pneumatic. 8. Larynx of birds is non-functional.

Instead syrinx is present. 9. Lungs contain external air sacs. 10. Eggs possess great amount of yolk.

They are called macrolecithal eggs. 11. Birds are oviparous.

1. Wings are absent except in bats. 2. Feathers and scales are absent. Hairs are

present. 3. Skin bears a number of sweat and oil

glands. 4. Females have mammary glands for

feeding the young. 5. A muscular partition called diaphragm is

present between thorax and abdomen. 6. Jaws do not form beak. Teeth are

present. 7. Bones of mammals do not possess air

cavities. 8. Larynx of mammals is functional. Syrinx

is absent. 9. External air sacs do not occur in lungs. 10. Eggs have no or tiny amount of yolk,

such eggs are called microlecithal eggs. 11. Mammals are viviparous with the

exception of prototherians.

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Class-9th (Biology)

Topic: Diversity in Living Organisms Worksheet- 3

1. How do poriferan animals differ from coelenterate animals ? 2. How do annelid animals differ from arthropods ? 3. What are the differences between amphibians and reptiles ? 4. What are the differences between animals belonging to the Aves group and those in the mammalia group ? 5. Explain how animals in vertebrata are classified into further subgroups. 6. List any three differences between the aves and reptilia group. 7. Identify two features of chordates. 8. Define the terms and give one example each of: (a) Bilateral symmetry (b) Coelom (c) Triploblastic. 9. Write any three differences between amphibia and mammalia belonging to kingdom Animalia. 10. Identify animal groups having: (a) soft bodied animals supported by calcareous shells. (b) spiny body with radial body symmetry. (c) Bones light and hollow. (d) External ear or pinna. 11. Give one point of difference between notochord and nerve cord. 12. List a few flight adaptations in Birds. 13. Why whales are not grouped in the fishes ? 14. How do animals of Porifera differ from animals of Cnidaria ? 15. Write down four general characters of cnidarians (coelenterates). Give two examples. 16. Write down four main characters of Platyhelminthes. Give two examples. 17. Write four characters of Annelida. 18. Define the term hermaphrodite. Give two examples. 19. Write down four main characteristics of Arthropoda. Give two examples. 20. Write the scientific names of:- (a) Prawn (b) Squid (c) House fly (d) Apple snail (e) Star fish (d) Fresh water mussel. 21. What are adaptations in fishes due to which they are aquatic ? 22. What are differences between:-

(a) Cartilaginous fishes and bony fishes. (b) Amphibia and Reptilia.

23. Name major phyla of Animal kingdom. Write down one character and one example of each of them.

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24. What are Pisces ? Classify and explain two different kinds of fishes with the help of suitable examples.

HOTS 1. What are the difficulties that you would face in classification of animals, if common fundamental features are not taken into account ? 2. How useful is the study of the nature of body cavity and coelom in the classification of animals ? 3. Distinguish between intracellular and extracellular digestion. 4. What is the difference between direct and indirect development ? 5. What are the peculiar features that you find in parasitic platyhelminthes ? 6. What are the reasons that you think of for the arthropods to constitute the largest group of the animal kingdom ? 7. “All vertebrates are chordates but all chordates are not vertebrates”. Justify the statement . 8. How important is the presence of air bladder in Pisces ? 9. What are the modifications that are observed in birds that help them fly ? 10. Segmentation in the body is first observed in which of the following: (a) Platyhelminthes (b) Aschelminthes (c) Annelida (d) Arthropoda. 11. Prepare a list of some animals that are found parasitic on human beings.

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Topic: Diversity in Living Organisms

Worksheet- 4

Multiple Choice Questions 1. Find out incorrect sentence

(a) Protista includes unicellular eukaryotic organisms (b) Whittaker considered cell structure, mode and source of nutrition for classifying the organisms in five kingdoms (c) Both Monera and Protista may be autotrophic and heterotrophic (d) Monerans have well defined nucleus

2. Which among the following has specialised tissue for conduction of water ? (i) Thallophyta (ii) Bryophyta (iii) Pteridophyta (iv) Gymnosperms

(a) (i) and (ii) (b) (ii) and (iii) (c) (iii) and (iv) (d) (i) and (iv)

3. Which among the following produce seeds ? (a) Thallophyta (b) Bryophyta (c) Pteridophyta (d) Gymnosperms

4. Which one is a true fish ? (a) Jellyfish (b) Starfish (c) Dogfish (d) Silverfish

5. Which among the following is exclusively marine ? (a) Porifera (b) Echinodermata (c) Mollusca (d) Pisces

6. Which among the following have open circulatory system ? (i) Arthropoda (ii) Mollusca (iii) Annelida (iv) Coelenterata (a) (i) and (ii) (b) (iii) and (iv) (c) (i) and (iii) (d) (ii) and (iv)

7. In which group of animals, coelom is filled with blood? (a) Arthropoda (b) Annelida (c) Nematoda (d) Echinodermata

8. Elephantiasis is caused by: (a) Wuchereria (b) Pinworm (c) Planarians (d) Liver flukes

9. Which one is the most striking or (common) character of the vertebrates? (a) Presence of notochord (b) Presence of triploblastic condition (c) Presence of gill pouches (d) Presence of coelom

10. Which among the following have scales ? (i) Amphibians (ii) Pisces (iii) Reptiles (iv) Mammals

(a) (i) and (iii) (b) (iii) and (iv) (c) (ii) and (iii) (d) (i) and (ii)

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11. Find out the false statement (a) Aves are warm blooded, egg laying and have four chambered heart (b) Aves have feather covered body, fore limbs are modified as wing and breathe through lungs (c) Most of the mammals are viviparous (d) Fishes, amphibians and reptiles are oviparous

12. Pteridophyta do not have (a) root (b) stem (c) flowers (d) leaves

13. Identify a member of porifera (a) Spongilla (b) Euglena (c) Penicillium (d) Hydra

14. Which is not an aquatic animal? (a) Hydra (b) Jelly fish (c) Corals (d) Filaria

15. Amphibians do not have the following (a)Three chambered heart (b) Gills or lungs (c) Scales (d) Mucus glands

16. Organisms without nucleus and cell organelles belong to (i) fungi (ii) protista (iii) cyano bacteria (iv) archae bacteria

(a) (i) and (ii) (b) (iii) and (iv) (c) (i) and (iv) (d) (ii) and (iii)

17. Which of the following is not a criterion for classification of living organisms? (a) Body design of the organism (b) Ability to produce one’s own food (c) Membrane bound nucleus and cell organelles (d) Height of the plant

18. The feature that is not a characteristic of protochordata? (a) Presence of notochord (b) Bilateral symmetry and coelom (c) Jointed legs (d) Presence of circulatory system

19. The locomotory organs of Echinodermata are (a) tube feet (b) muscular feet (c) jointed legs (d) parapodia

20. Corals are (a) Poriferans attached to some solid support (b) Cnidarians, that are solitary living (c) Poriferans present at the sea bed (d) Cnidarians that live in colonies

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21. Who introduced the system of scientific nomenclature of organisms (a) Robert Whittaker (b) Carolus Linnaeus (c) Robert Hooke (d) Ernst Haeckel

22. Two chambered heart occurs in (a) crocodiles (b) fish (c) aves (d) amphibians

23. Skeleton is made entirely of cartilage in (a) Sharks (b) Tuna (c) Rohu (d) None of these

24. One of the following is not an Annelid (a) Earthworm (b) Nereis (c) Leech (d) Urchins

25. The book Systema Naturae was written by (a) Linnaeus (b) Haeckel (c) Whittaker (d) Robert Brown

26. Carl Von Linnaeus was involved with which branch of science? (a) Morphology (b) Taxonomy (c) Physiology (d) Medicine

27. Real organs are absent in (a) Mollusca (b) Coelenterata (c) Arthropoda (d) Echinodermata

28. Hard calcium carbonate structures are used as skeleton by (a) Echinodermata (b) Protochordata (c) Arthropoda (d) Nematoda

29. Differentiation in segmental fashion occurs in (a) Leech (b) Starfish (c) Snails (d) Ascaris

30. In taxonomic hierarchy family comes between (a) Class and Order (b) Order and Genus (c) Genus and Species (d) Division and Class

31. 5-Kingdom classification has given by (a) Morgan (b) R. Whittaker (c) Linnaeus (d) Haeckel

32. Well defined nucleus is absent in (a) blue green algae (b) diatoms (c) algae (d) yeast

33. The ‘Origin of Species’ is written by (a) Linnaeus (b) Darwin (c) Hackel (d) Whittaker

34. Meena and Hari observed an animal in their garden. Hari called it an insect while Meena said it was an earthworm. Choose the character from the following which confirms that it is an insect.

(a) Bilateral symmetrical body (b) Body with jointed legs (c) Cylindrical body (d) Body with little segmentation

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