Chapter 6 Animal Kingdom Part 6 (Reptilia, Aves and Mammalia) by TEACHING CARE online tuition and coaching classes
Chapter 6 Animal Kingdom Part 6 (Reptilia, Aves and Mammalia) by TEACHING CARE online tuition and coaching classes
General Characters :
Reptiles represent the first class of vertebrates fully adapted for life on land.The characters of reptiles are a combination of the characters found in fishes and amphibians on one hand and in birds and mammals on the other. The class name refers to the mode of locomotion (L., repere or reptum, to creep or crawl), and the study of reptiles is called Herpetology (Gr., herpeton, reptiles).
- Predominantly terrestrial, mostly carnivorous, air–breathing, cold– blooded, oviparous and tetrapodal vertebrates.
- Body bilaterally symmetrical and divisible into 4 regions-head, neck, trunk and
- Two pairs of pentadactyle limbs, Digits provided with horny However, limbs absent in a few lizards and all snakes.
- Exoskeleton of horny epidermal scales, shields, plates and
- Skin dry, cornified and devoid of
- Mouth Jaws bear simple conical teeth. In turtles teeth replaced by horny breaks.
- Alimentary canal opens into a cloacal
- Endoskeleton bony. Skull with one occipital condyle (monocondylic). A characteristic T–shaped inter clavicle
- Heart usually 3–chambered, 4–chambered in crocodiles. Sinus venosus 2 systemic arches present. Red blood corpuscles oval and nucleated. Cold–blooded.
- Respiration by lungs throughout
- Kidney Excretion uricotelic.
- Brain with more developed cerebrum than in Amphibia. Cranial nerves 12
- Lateral line system Jacobson’s organs present in the roof of mouth used for smell.
- Sexes Male usually with a muscular copulatory organ.
- Fertilization internal. Mostly oviparous. Large yolky meroblastic eggs covered with leathery shells, always laid on Embryonic
membranes (amnion, chorion, yolk sac and allantois) appear during development. No metamorphosis. Young resemble adults.
There are more than 7,000 living and several extinct species of reptiles, grouped into 16 orders of which only 4 are living.
Subclass I Anapsida – Primitive reptiles with a solid skull roof. No temporal openings.
Order 1. Chelonia or Testudinata : (Gr., chelone, turtle; L., testudo, turtle)
- Body short, broad and
- Limbs clawed and or webbed, paddle-like.
- Body encased in a firm shell of dorsal carapace and ventral plastron, made by fusion of dermal bony plates. Thoracic vertebrae and ribs usually fused to
- Skull anapsid, with a single nasal opening and without a parietal Quadrate is immovable.
- No sternum is
(6) Teeth absent. Jaws with horny sheaths.
- Cloacal aperture a longitudinal
- Heart incompletely 4–chambered with a partly divided
- Copulatory organ single and
- They include marine turtles, freshwater terrapins and terrestrial
Examples – Chelone, Testudo, Trionyx.
Subclass II Euryapsida (extinct) : Skull with a single dorso–lateral temporal opening on either side bounded below by postorbital and squamosal bones.
Subclass III Parapsida (extinct) : Skull with a single dorso–lateral temporal opening on either side bounded below by the supra temporal and post frontal bones.
Subclass IV Synapsida (extinct) : Skull with a single lateral temporal opening on either side bounded above by the postorbital and squamosal bones.
Subclass V Diapsida : Skull with two temporal openings on either side separated by the bar of postorbital and squamosal bones.
Order 2. Rhynchocephalia : (L., rhynchos, snout + Gr., kephale, head)
- Body small, elongated, lizard-like.
- Skull Parietal foramen with vestigeal pineal eye present. Quadrate is fixed.
- Numerous abdominal ribs
- Heart incompletely four
- No copulatory organ in
Example: They are represented by a single living species, the “tuatara” or sphenodon punctatum of New Zealand.
Order 3. Squamata : (L., squama, scale or squamatus, scaly)
- Skull Quadrate movable.
- Heart incompletely 4–chambered. It includes snakes and lizards
Lacertilia – Lizards Ophidia – Snakes
- Saurology is the study of
- Serpentology or ophiology is the study of
- Lizards have 2 pairs of pentadactyl limbs with
- Autotomy is voluntary breaking of tail to confuse enemy. Tail of most lizards is easily broken off when threatened or seized by a A new tail is soon regenerated but without vertebrae.
- Most lizards are oviperous, except two viviparous lizards-
Phrynosoma and Chameleon.
- Draco- ‘flying dragon’, is a lizard which glides with the help of
- The only poisonous lizard in the world is Heloderma (Gila monster), also called ‘Beaded lizard’ because its scales resemble
- Heloderma rarely bites man, but is Its poison is neurotoxic.
- Limbs are absent in lizards like ; Ophiosaurus, Anguis and Rhineura, called as glass
- Barkudia is a limbless lizard from South
- The glass snakes Ophiosaurus derives its name from its ability to break off its tail when
- A limbless lizard has movable eyelids and external ear opening which are absent in
- Lizards are mostly carnivarous, but a herbivorous lizard is lguana from South and Central America.
- The largest living lizard in the world is the ferocious dragon,
Varanus komodoensis, found in Malaya Archipelago.
- Python and Boa have vestigial pelvic girdle and
- Sternum, pectoral girdle, tympanum and urinary bladder are absent in
- Eyelids of snakes are immovable, nictitating membrane is absent and lungs
- The bifid tongue of snakes is sensitive to both odours and
- A snake lacks middle
- Moulting or ecdysis: Snakes shed off scaly epidermis of skin periodically usually in one This is termed moulting or
ecdysis (moulting also occurs in arthropods). Snakes are not found in New Zealand.
- Locomotion of snakes is carried out by ribs and large ventral
- The largest nonpoisonous snake is Python.
- Eryx johnii or sand boa has a small, non-prehensile thick tail giving a false resemblance to head, hence called ‘double headed snake’. Except Vipera russelli and Hydrophis, most of the snakes are
- Cobras, kraits, vipers, sea snakes and coral snakes are common poisonous snakes. All poisonous snakes possess poison gland which are modified superior labial or parotid glands. The poison i fangs (teeth) are maxillary teeth present on maxilla. Snake poison is a mixture of enzymes and specific toxins and is a good digestive It is fatal only when mixed in blood. The snake venoms are two types- neurotoxic and haemotoxic. The poisons of cobra, krait and sea snakes are neurotoxins. Neurotoxins cause death by paralysis of respiratory muscles and asphyxiation. Haemotoxins are typical of vipers. Haemotoxins cause tissue destruction and widespread hemorrhage. Proteolysin is present in the venom of viper. The venom of viper affects circulatory system. The best medicine to treat snake bite is a antivenin or antivenom serum which contain antibodies. Different antivenins are required against different snakes due to differences in the qualities of snake venoms. Benadryl and antisera are used to couteract-the effect of haemotoxins. An antivenin is prepared by injecting a horse with increasing doses of a snake venom until the horse becomes completely immunized . Blood serum of horse is collected and preserved. In India, antivenin injections are prepared at Haffkin’s institute, Mumbai and Central Rsearch Institute, Kausauli (Simla). Sea snakes are poisonous; Two common sea snakes are Hydrophis and Enhydrina.
Identification of poisonous and non poisonous snakes:-
The arrangement and size of scales, plates and shields help in identification of poisonous and non-poisonous snakes. The common characteristics of both the types are:
- See the scale pattern on the ventral side(underside) of the snake. If the scales are small and uniform, or are transversely long but some rows of small scales of the back are visible on the underside, it is non-poisonous.
- If the scale pattern on the ventral side shows transversely arranged plates and no small scales of the back reach the underside, then it may be poisonous or non-poisonous. To confirm, watch the scale pattern on the top of the head; if it is covered with small scales, it is one of the deadly poisonous snakes such as a viper.
- But if the scales on the head are large shields or plates, it may be non-poisonous or one of these poisonous snakes: a pit-viper, a cobra, king cobra, a coral snake. To confirm, look at the side of the
- If a pit larger than the nostril is present between the nostril and the eye, it is a pit-viper.
- If no pit is present but the third upper labial (supra labial) scale touches the nasal scale and the eye, it is a cobra, king cobra or a coral snake, Naja naja (cobra).
- If none of the two above characters is present, then look for the following two characters:
- the middle row of scales on the back enlarged and
- the fourth scale on the lower lip (infra labial) along the margin of the lower jaw is the largest, then it is a krait.
- If (i), (ii) and (iii) characters are absent, then its non-
- All sea snakes are poisonous except one species. They have large flattened scales on the head and the tails are flattened
Order 4. Crocodilia : (G., krokodeilos, Crocodile)
- Skin thick having scales, bony plates and
- Skull Quadrate immovable. No parietal foramen.
- Abdominal ribs
- Heart completely four chambered. Examples – Crocodylus, Gavialis, Alligator
- The birds are feather covered, air-breathing, warm-blooded, oviparous, bipedal flying
- They have two pairs of limbs. Forelimbs are modified as wings for Hind limbs or legs are large, and are variously adapted for walking, running scratching, perching, food capturing, swimming etc.
- Exoskeleton epidermal and
- Skin dry without glands except the oil or preen gland/ uropygeal gland at the base of tail.
(s5) Pectoral muscles of flight are well developed.
- Skull smooth and monocondylic, having a single occipital condyle. Sutures
- Vertebral column Vertebrae heterocoelous (saddle-shaped).
- Sternum large, usually with a vertical, mid ventral keel for attachment of large flight
- Ribs double-headed (bicephalous) with posteriorly directed uncinate
- Both the clavicles and a single inter clavicle fuse to form a V– shaped bone, called furcula or wishbone.
- Heart completely four chambered. No sinus venosus or truncus Only right aortic (systemic) arch persists in the adult. Renal portal system vestigial. Blood corpuscles nucleated.
- Birds are the first warm blooded vertebrates. Body temperature is constant (homoiothermous).
- Respiration by compact, spongy, distensible lungs continuous with air-sacs.
- Larynx without vocal cords. A sound box or syrinx for producing voice lies at or near the junction of trachea and
- Kidneys metanephric. Uterus open into cloaca. Urinary bladder Birds are urecotelic. Excretory matter of urates is eliminated with faeces.
- Sexes Sexual dimorphism well marked.
- Fertilization internal, preceded by copulation and Females oviparous.
- Eggs develop by external incubation. Cleavage discoidal, Development direct, Extra-embryonic membranes (amnion, chorion, allantois and yolk-sac) present.
- Parental care well
About 9,000 living species of birds are known. 25 avian orders are recognized. Class Aves is first divided into two subclasses.
Sub-Class I. Archaeornithes : Gr., archios, ancient + ornithos, bird)
- Extinct, Jurassic birds of Mesozoic Age, about 155 million years
- Wings primitive, with little power of flight. (3)Sternum without a keel.
(5) In Archacopteryx beak in toothed. This sub-classes includes a single order
Order Archaeopterygiformes : Example – Archaeopteryx lithographica, from Jurassic or Bavaria, Germany; one specimen lying in the British museum, London, the other lying in the Berlin.
Sub-class II. Neornithes : (Gr., neos, modern+ ornithos, Birds)
- Modern as well as extinct post-Jurassic
- Wings usually well-developed and adapted for flight, with few
- Teeth absent except in some fossil
- Sternum usually with a
- Abdominal ribs absent
This sub-class is divisible into 4 super-orders:
Super-order 1. Odontognathae : (Gr., odontos, teeth)
- Extinct, Upper Cretaceous
- Jaws with
Order 1. Hesperornithiformes Example – Hesperornis. Order 2. Ichthyornithiformes Examples – Ichthyornis.
Super-order 2. Palaeognathae or Ratitae : (Gr., palaios old + gnathos jaw; L., ratis, raft).
- Modern big-sized, flightless, running birds, without
- Wings vestigial or rudimentary; feathers without interlocking
- Rectrices absent or irregularly
- Oil gland absent, except in Tinamus and
- Sternal keel vestigial, or absent
- Clavicles are small or
- Pectoral muscles poorly
- Syrinx is absent
They are grouped in 7 orders as follows;
Order 1. Struthioniformes : (Gr., struthio, ostrich + form) Examples – True ostriches (Struthio camelus) of Africa Order 2. Rheiformes : (Gr., Rhea, mother of Zeus + form)
Examples – American ostriches or common rhea (Rhea americana). Order 3. Casuariformes Examples– Cassowaries (Casuarius) of australia, and New Guinea and Emus (Dromaius novaehollandiae) of New Zealand Order 4. Apterygiformes Examples– Kiwis (Apteryx) or New Zealand.
Order 5. Dinornithiformes Examples – Moas (Dinornis maximus) of New Zealand
Order 6. Aepyornithiformes Examples –Giant Elephant-birds of Africa and Madagascar. Aepyornis titan.
Order 7. Tinamiformes Examples – Tinamou (Tinamus).
Super-order 3. Impennae
- Most modern, usually small-sized, flying
- Wings well-developed ; feathers with interlocking
- Rectrices present and arranged
- Pterylae are
- Oil gland is
- Sternum with a well-developed
- Pygostyle is present
Super order 4. Neognathae : The super-order Neognathae includes several orders. For the sake of convenience they may be grouped into at least 6 homogeneous ecological groups, as follows :
Group A. Arboreal Brids : It includes majority of birds spending most of their lives in and around shrubs and trees.
Order 1. Passeriformes : (L., passer, sparrow + form). Feet are adapted for perching, while beaks for cutting. Examples : Common house sparrow (Passer domesticus), common house crow (Corvus splendens) Order 2. Piciformes : (L., picus, wood pecker + form) It includes woodpeckers, sap-suckers. Examples : Yellow fronted pied woodpecker (Dendrocopos mahrattensis).
Order 3. Columbiformes : (L., columba, dove + form) It includes doves and pigeons Examples : Blue rock pigeon (Columba livia). Green pigeon (Crocopus), extinct dodo (Raphus)
Order 4. Psittaciformes : (L., psitacus, parrot + form) It includes parrots, parakeets, etc. Examples : Large Indian parakeet (Psittacula eupatria).
Group B. Terrestrial Brids : These birds are perfectly able to fly but spend most of their time walking or running on ground.
Order 5. Galliformes : (L., gallus, a cock + form) It includes gamebrids notable for their palatability, massive scratching feet, short and powerful flight. Examples : Red jungle fowl (Gallus), peafowl (Pavo cristatus),
Order 6. Cuculiformes : (L., cuculus, cuckoo + form) It includes cuckoos. Examples : Cuckoo (Cuculus canorus), Koel (Eudynamis scolopaeous).
Group C. Swimming and Diving Birds
Order 7. Anseriformes : (L., anser, goose + form) Aquatic birds such as geese, swans and ducks belong to this order. Examples : Wild duck or mallard (anas), kcommon teal (nettion crecca), bar-headed goose (Anser indica)
Order 8. Coraciiformes : (Gr., korax, crow or raven + form) It includes kingfishers and their allies. Examples : White breasted kingfisher
(Halcyon smyrnensis), pied kingfisher (Ceryle rudis)
Order 9. Gaviformes : (L., gavia, sea mew = form) It includes marine birds, called loons (gavia) represented by only four species.
Order 10. Podicipediformes or Colymbiformes (Gr. kolymbos, diving bird) It includes grebes (Podicipes), often called divers.
Order 11. Procellariformes : (L., Procella, a tempest + form) It includes tube-nosed, seabirds such as albatrosses (Diomedea).
Order 12. Pelecaniformes : (L., pelicanus, pelican + form) It includes pelicans. Examples : Pelicans (Pelecanus).
Group D. Shore Birds and Wading Birds These aquatic birds seldom swim or dive beneath the water to any great extent.
Order 13. Charadriiformes : (NL., charadrius, genus of plovers + form) This order includes a rather diverse group of shore birds characterized by long wading legs and webbed toe. Examples : Red wattled lapwing) Order 14. Ciconiiformes : (L., ciconia, a stork + form) It includes long– legged, marshy wading birds with long snake-like neck.Examples : Cattle egret (Bubulcus ibis), heron (Ardea herodias), flamingo (Phonicopterus).
Order 15. Gruiformes : (L., grus, crane + form) It includes crane-like wading birds with long legs. Examples : Common coot (Fulica atra), Group E. Birds of Prey
Order 16. Falconiformes : (L., falco,falcon + form) The diumal birds of prey with sharp hooked beaks and strong curved claws.
Types of Feathers
- The quills are large feathers present in wings and
- It has a central axis called
- A small proximal parts of the shaft is hollow and translucent and is termed as
- The long-distal, solid, opaque part of the stem is known as
- An umbilical groove extends all along the ventral side of
- Small hole on the proximal end of calamus is known as umbilicus, the hole on the distal end of calamus is known as superior umbilicus.
- Each vane is composed of parallel filaments, the barbs. Each barb contains barbules.
- The distal barbules of each barb bear small
- Emu bird have an after shaft as long as the main
- Coverts: They are small feathers present in the wings and They fill up the gaps left between the bases of the quills. They have short calamus in comparison to quills.
- Contours : They are small feathers that cover the body. They resemble the quills but their barbs are not so strongly joined and can be separated
- Filoplumes : They occur beneath contour feathers, very small in size, consists of long calamus bearing at the tip of a few weak free barbs with
- Down feathers : They cover the newly hatched bird also called as natal covering or the nestling downs. They consists of short calamus, reduced rachis bearing flexible barbs with short They are found beneath contours.
- Bristles : They have short calamus, a long rachis with a few vestigeal barbs at its base. Bristles occur near the mouth in the fly-catchers.
- The first digit of the hand (thumb or pollex), bears a tuft of small feathers known as bustard wing or alaspuria or false wing.
- The mammals are air-breathing, warm blooded, viviparous, tetrapod vertebrates having body covered with hairs.
- Two pairs of pentadactyle limbs, each with 5 or fewer digits. Hind limbs are absent in cetaceans and
- Exoskeleton includes non living horny, epidermal hairs, spines, scales, claws, nails, hoofs, horns, bony dermal plates,
- Skin highly glandular containing sweat, sebaceous (oil) and occasionally scent glands in both the sexes. Females also have functional mammary glands with teats producing milk for suckling the
- Endoskeleton completely ossified. Skull dicondylic having 2 occipital Cranium large. A single zygonmatic arch present. Otic bones fused into periotic which forms tympanic bulla with tympanic. Each half of lower jaw consists of a single bone, the dentary, which articulates with squamosal bone of skull. Vertebrae with flat centra (acoelous). Cervical vertebrae usually seven. Ribs bicephalous.
- Teeth may be of several types (heterodont), borne is sockets (thecodont) and represented by two sets (diphyodont).
- Respiration always by lungs (pulmonary). Glottis protected by a fleshy and cartilaginous Larynx contains vocal cords.
- Heart four chambered with double
- Brain highly developed. Both cerebrum and cerebellum are large and convoluted. Optic lobes small and 4 in number called corpora quadrigemina. Corpus callosum present between both the cerebral Cranial nerves 12 pairs.
- Sense organs well Eyes protected by eyelids, the upper one is movable. External ear opening is protected by a large fleshy, cartilaginous flap called pinna. Middle ear cavity with 3 ear ossicles– malleus, incus and stapes. Cochlea of internal ear spirally coiled.
- Fertilization internal preceded by
- Except egg-lying monotremes, mammals are viviparous and give birth to living young ones.
Classification of Mammal
Subclass I prototheria : (Gr., protos, first + therios, beast). Primitive, reptile-like, oviparous or egg-lying mammals.
Order 1. Monotremata. (Gr., monos, single + trema, opening), Cloacal opening present Confined to Australian region. Examples : Monotremes. Platypus or duckbill (ornithorhynchus), spiny anteater (Tachyglossus = Echidna)
Sub class II. Theria : (Gr., ther, Theria are subdivided into 2 living infraclasses)
Infraclass 1. Metatheria : (Gr., meta, between or after). Pouched and viviparous mammals without or with a rudimentary yolk sac placenta. Confined mostly to Australian region.
Order 2. Marsupialia : (Gr., marsypion, pouch). Young ones are born in a very immature state, and complete their development while attached to teats or nipples in the abdominal pouch or marsupium. Vagina double, uterus double.
Examples : Marsupials. Opossum (Didelphis). Kangaroo (macropus), koala (phascolarctos) Kangaroo is the native of Australia
Infraclass 2. Eutheria : (Gr., eu, true + therios + beast) Higher viviparous mammals with true placenta and without marsupium. Young ones born in a relatively advanced stage. Eutherians constitute majority of living mammals arranged in 16 orders.
Order 3. Insectivora : (L., insectum, insect + vorare, to eat) Small insectivorous mammals with long pointed snout.
Examples : Mole (Talpa), common shrew (Sorex), hedgehogs (Erinaceus, Paraechinus)
Order 4. Chiroptera : (Gr., Cheiros, hand + pteron, wing) It includes flying mammals or bats in which forelimbs are modified into wings. Hind legs short and included in wing membrane
Order 5. Dermoptera : (Gr., derm, skin + pteron, wing). Nocturnal in
trees. Gliding with the help of skin folds. Examples : One living genus Cynocephalos
Order 6. Edentata : (L., edentatus, toothless) Teeth absent or reduced to molars. Without enamel. Examples : Giant ant eater (Mryrmecopha) armadillo (Dasypus),
Order 7. Pholidota : (Gr., pholis, a scale) Body covered with large overlapping scales with sparse hair in between. No teeth. Long and protrusible snout used to capture insects. Examples : Single genus of scaly anteaters pangolins (Manis)
Order 8. Tubulidentata : (L., tubulus tube like + dens, tooth) Examples : Single genus of pig-like aardvark or Cape anteater (Orycteropus)
Order 9. Primates : (L., primus, of the first rank) Generalized or primitive mammals except for great development of brain. Mostly arboreal. Eg. monkeys, apes and human beings.
Order 10. Rodentia : (L., rodo, gnaw) Largest order including usually small gnawing mammals. Each jaw with one pair of long, rootless, chisel-like incisors growing throughout life. No canines. Examples : Rat (Rattus), Mouse (Mus) squirrel (Funambulus)
Order 11. Lagomorpha : (Gr., logos, hare + morphe, form) With a second pair of small upper incisors behind first pair of large chisel like incisors. No canines. Examples : Rabbit (Oryctolagus), hare (Lepus) Order 12. Cetacea : (Gr. ketos or L., cetus, a whale)
Large marine fish-like mammals well adapted for aquatic life with pectoral limbs modified into broad paddle-like flippers. No claws, no hind limbs and no external ears. The living Cetacea are divided into two suborders Odontoceti (toothed whales) and Mysticeti (whalebone whales).
Order 13. Sirenia : (Gr., siren, sea nymph). Large, clumsy herbivorous, aquatic mammals with paddle-like forelimbs, and no hindlimbs. No external ears. Muzzle blunt. Hairs few. Inhabit estuaries and coastal
sea. Examples : Manatee (Trichechus), dugong (Dugong = Halicore), recently extinct Steller’s sea-cow (Rhytina)
Order 14. Carnivora : (L., caro, tlesh + vorare, to eat) Small to large predatory, flesh-eating mammals. Examples : Dog (Canis familiaris), Wolf (C. lupus), Jackal (C. aureus), Walrus (Odobenus), common seal (Phoca)
Order 15. Hyracoidea : (Gr., hyrax, shrew + eidos, form) Small, guinea- pig like mammals distantly related to elephants. No canines. Cheek teeth lophodont. Example : Conies (Hyrax = Procavia).
Order 16. Proboscidea : (Gr., pro, in front + boskein, to eat) Largest living land animals having large heads, massive ears, thick practically hairless skins (pachyderm), bulky straight legs and 3 to 5 toes with small, nail like hoofs. Prominent feature is the nose and upper lip modified as an elongated proboscis or trunk. Two upper incisors elongated as ivory tusks. Cheek teeth lophodont.
Examples : Indian or Asiatic elephant (Elephas maximus), African elephant (Loxodonta africana)
Order 17. Perissodactyla : (Gr., perissos, odd + dactylos, toes) The odd- toed hoofed mammals or ungulates with an odd number of toes (1 or 3) incisors present in both jaws. Examples : Horse (Equus cabalus), wild ass (Equus asinus), Zebra (Equus zebra)
Order 18. Artiodactyla : (Gr., artios, even + dactylos digit) The even- toed hoofed mammals with an even number of toes (2 or 4). Incisors and canines in upper jaw usually absent. Stomach four chambered.
Many with antlers or horns. Examples : Pig (Sus), common hippopotamus (Hippopotamus amphibius), camel (Camelus), deer (Cervus), musk deer (Moschus), sheep (Ovis).
Practice Test Paper
- Only poisonous lizard of the world is
(a) Draco (b) Heloderma (c) Sphenodon (d) Varanus
- Carapace is present in
(a) Toad (b) Bird (c) Frog (d) Tortoise 3.Which is not aerial adaptation of Birds
(a) Single ovary (b) Pneumatic bone (c) Gizzard (d) Keeled sternum
- Archaeopteryx called a connecting link, carried the characters of
(a) Reptile and bird (b) Reptile and mammal (c) Fish and amphibian (d) Amphibian and reptile
- Pneumatic bones of birds
(a) Increase the respiratory rate (b) Increase the heart beat rate (c) Increase the CO2 output (d) Increase the buoyancy
- The vertebrae of birds are characteristically
(a) Heterocoelous (b) Acoelous (c) Opisthocoelous (d) Amphicoelous 7.Egg-laying mammals are grouped as
(a) Eutheria (b) Prototheria (c) Rodentia (d) Metatheria 8.External ears are characteristics of
(a) Birds (b) Mammals (c) Birds and mammals (d) Mammals and reptiles
- Corpus callosum is present only in
(a) Amphibia (b) Reptilia (c) Birds (d) Mammalia
- In which of following group of mammals, the placenta is absent
(a) Prototheria (b) Metatheria (c) Eutheria (d) Theria
- Jacobson’s organs present in the roof of mouth are used for……
- Body of Chelonia is encased in a firm shell of dorsal………….. and
- A single living species, the “tuatara” or sphenodon punctatum of New Zealand belongs to the order…..
- What is autotomy
- The only poisonous lizard in the world is …………….
- The largest living lizard in the world is the ferocious dragon……….
- What is the mode of action of neurotoxins ?
- What is furcula in aves
- Briefly mention about types of teeth found in mammalia
- Write briefly about marsupials
Answers and Solutions
- Autotomy is voluntary breaking of tail to confuse enemy. Tail of most lizards is easily broken off when threatened or seized by a predator.
- Heloderma (Gila monster)
- Varanus komodoensis
- Neurotoxins cause death by paralysis of respiratory muscles and asphyxiation
- Both the clavicles and a single inter clavicle fuse to form a V– shaped bone, called furcula or wishbone
- Teeth may be of several types (heterodont), borne is sockets (thecodont) and represented by two sets (diphyodont).
- Young ones are born in a very immature state, and complete their development while attached to teats or nipples in the abdominal pouch or marsupium. Vagina double, uterus
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