Reptiles power point presentation........

reptiles................

1. Reptiles

2. Evolutionary Perspective Reptiles were first vertebrates that possess amniotic eggs Amniotic egg have extra embryonic membranes Those membrane perform following functions 1. These protect embryo from desiccation 2. These support the embryo like cushion 3. These membrane promote gas transfer 4. These membrane remove waste material

3. Amniotic egg structure Shell : birds and reptiles have hard or leathery shell. This shell protect the developing embryo Albumin: the albumin cushion the embryo. It also provide moisture and nutrients to the embryo Yolk: the yolk supply food to the embryo The amniotic egg is the major synapomorphy It distinguishes the reptiles, birds and mammals from non amniotic vertebrates

4. Adaptive radiation in reptiles Adaptation: characters change according to surrounding environment Radiation: Formation of many species from one common ancestor “It is differentiation of a single ancestor into many species hat cause different morphological and physiological traits according to their habitat”

5. Groups of Reptiles Three groups of reptiles Anapsid No posterior lateral opening Turtles Diapsid : 2 postero lateral openings 2 subclases 1. leidousoria snakes, lizards, tutara ) 2. Archosouria : dinosours Living archosours are crocodiles

6. Synapsid O ne opening in temporal region All of synapsid become extinct It give rise to mammals

7. Characteristics of reptiles Their surface has one surface condyle for articulation with the first neck vertebrae Respiration takes place by lungs They have internal fertilization and amniotic egg Reptiles have dry skin. It has keratinized epidermal scales. Keratin is a resistant protein. It is found in epidermal derived structures of amniotes. It is chemically bounded to phospholipids. Therefore, it prevent loss of water through body surface They are found in all continent except Antarctica. However they are most abundant on tropical and subtropical environments.

8. ORDERS Order Testudines Order Renchocephalia Order Squamata Order crocodilia

9. ORDER TESTUDINES Turtles (L. testudo , tortoise) Teeth are abundant in adults. The are replaced by a horny beak. They have keratinized beak They have short broad body Their shell consist of dorsal carapace and ventral plastron Turtles have 225 species. They have a bony shell Their limbs articulate internally with the ribs Example: Turtle

10. Shell in turtle Carapace : the dorsal portion of the shell is the carapace. Carapace is formed by the fusion of vertebrae, ribs and bones in the dermis of skin. Keratin cover the bone of the carapace Plastron: the ventral portion of the shell is plastron. It is formed from bones of the pectoral girdle and dermal bone Keratin also cover it The shell of some turtle have flexible area or hinges These hinges attach the anterior and posterior edges of the plastron The hinges close the opening of the shell during withdrawal of body into the shell Cervical vertebrae Turtle have eight cervical vertebrae These vertebrae articulated to form an S shaped structure It draws the head in to the shell

11. Reproduction and life span Long life pan Most reach at sexual maturity after seven or eight years They can live 14 or more years The age of large tortoise Age of tortoise of Galapagos island may be above 100 years All turtles are oviparous Female use their hind limbs to dig nest in the soil There they lay eggs Their clutches contain 5 to 100 eggs They cover eggs with soil Development takes from 4 months to one year Parent does not attend o the egg during this time The young are independent of the parent at hatching

12. Turtle in Danger Turtle have slow rate of growth They have long juvenile period They have high mortality rate The turtle are becoming extinct Dogs and other animals are hunting young turtles It has severely threatened some species of turtle They make nest on certain beaches years after year Observation program of sea turtle is difficult The have rage of thousands of kilometer of ocean

13. Order Renchocephalia Rhynchos , snout + kephole , head Renchocephalia has only one surviving species called tuatara ( Sphenodon punctalus ) It is lizard like reptile It has remain unchaged since it eveolved from extinct relatives ere present at the begening of mesozoic era, nearly 200 myo

14. Distinct features Tooth attachment and structures distinguish the tuatara from other reptiles. They have two rows of teeth on upper jaw and single row of teeth in the lower jaw They bite the bird with these teeth This biting can decapitate a small bird It was widely distributed in Newzee land The population of tuatara is affected b human influences and domestic animals It is now present in far of offshore islands It is protected by Newzee land law It is oviparous and it share underground burrows with ground nesting seabirds Tuatara come out of their burrows at dusk and dawn They feed on insects or sometime on vertebrates

15. Order Squamata Snakes, lizards Squamas, scale + ata hear They have specific character of skull and jaw They are more successful and diverse group of living reptiles Example: snakes, lizards

16. Sub orders Order S quamata has three suborders 1. S auria (Lizards) 2. Serpents (Snakes) 3. Amphisbeania (worm lizards)

17. Sub order Sauria Lizards 3,300 species Two pair of legs Few lizards are legless Vary in size Few cm to 3m Most are oviparous Some are oviparous or ovoviviparous They deposit eggs under rocks or debris or in burrows

18. Geckos C ommonly found on the walls of houses Body is short and stout They are nocturnal They produce sound of clicking They have large eyes Their pupil contract and narrow during the day and widen at night they have adhesive disk on their digits these disk help in clinging to the tree and walls

19. Iguanas Iguanas have heavy body They have short neck and distinct head this group include marine iguana of galapagos Island and flying dragon of south east Asia Draco has lateral fold of skin It is supported by ribs The ribs of Draco expand to form a gliding surface it can glide 30 m or more

20. Chameleons It is another group of iguana It is found in Africa and India Chameleon are adapted for arboreal lifestyles They use long sticky tongue to capture insects have ability to change color They change color in response to illumination, temperature, or their behavioral state

21. Venomous lizards 1. They are G ila monster ( H oloderma suspectum ) and maxican beaded lizard ( H oloderma horidum ) 2. These heavy bodied lizards live in southwestern North America 3. The surface of their teeth have grooves 4. Venom is released into these grooves 5. The lizards chew the prey and introduce venom into it 6. lizards bites are not fatal to human

22. Sub order serpents 2,300species Majority are non dangerous Only 300 species are venomous 30,000 to 40,000 die from snake bite annually Most of death in south east Asia In US 100 people die annually

23. Body Structure Elongated ,Lack limbs Contain more than 200 vertebrae and pair of ribs Joints between vertebrae makes body flexible Adaptation in skull for swallowing large prey Upper jaws are moveable in skull Upper and lower jaw are loosely joined Each half of jaw move independently Body is elongated and narrow Left lung is reduced, gallbladder right kidney and gonads are displaced most are oviparous e give birth to young one like New world boss and garter snake

24. Evolution of snake Earliest fossil of snake from 135 million years ago Some zoologist believe that earlier snakes were burrowers Loss of appendages and change in structure takes place for burrowing habits It is believed that early snakes were aquatic or in densely vegetative area that’s why loose legs

25. Suborder Amphisbenia Worm lizards 13 species They are specialized burrowers Live in soil Found in Africa, South America, the Caribbean and middle East Most are legless Skull is wedge or shovel shape A single median tooth present in upper jaw. It distinguish amphisbaena from other vertebrates Skin has ring like folds called annuli Their skin is loosely attached to body wall Skin bulges outward by the contraction of muscles They move easily forward and backward they named as amphisbaenia They feed on worms and small insects They are oviparous

26. Order crocodilia 21 species They have special skull characteristic i . Opening in skull in front of eye ii. Triangular eye orbit iii. Laterally compressed teeth Example: alligator, crocodile, gavial

27. Adaptations in crocodiles Little change occurs in crocodile over their 170 my history Snout: their snout is elongated Used to capture prey by a sideway movement of head Nostrils are at the tip of snout Animal can breath when it is submerged Air Passage way: there is flap of tissue near the back of tongue It form water tight seal Breathing takes place without inhaling water in the mouth The secondary plate is a plate of bone It separate the mouth and nasal passage way Tail: muscular elongated and laterally compressed tail It is used for swimming It is also used for offense and defense

28. Digestive system: Teeth are used only for seizing prey Food is swallowed as whole Hold large prey with limbs Stomach is gizzard like Swallow rocks and other object They used these rocks for breaking food Reproduction: Oviparous Display parental care like birds Nesting and parental care shows that both birds and crocodiles and common ancestor

29. Evolutionary Pressure Adaptations in chakwala : ( Sauromalus obesus ) Adaptation in summer: It can survive in late summer at tem above 40C Eat plants When plants wither, chakwala aestivate (summer sleep) to withstand these hot and dry conditions Chakwala disappear below ground during aestivation

30. Adaptation in winter: Temperature become moderate in winter Little rain fall Life still not possible Summer sleep enters into winter sleep Rainfall started in March Greenery and flowers appear in deseart Chakwala come out of sleep It drink water and store large amount under its skin

31. Defense from predator: Predator cannot prey chakwala easily If threatened it enters into rocks crevices It inflates its lungs with air It increase its girth Thus it form wedge against entrance of the rock There is friction of its scale against the rock Therefore chakwala cannot remove from rocks

32. External structure and locomotion Skin Thick skin, dry, keratinized No respiratory function Snakes have large belly scales Less glandular skin Skin glands secretes pheromones that function in sex recognition and defense Chromatophore are dermal in origin Cryptic coloration, mimicry Color function in sex recognition and thermoregulation

33. Ecdysis Process in which reptiles periodically shed their outer epidermal layers of the skin All reptiles undergoes ecdysis Blood supply do not moves in epidermis Outer cell loose contact with blood and die Ecdysis begin in head region

34. locomotion Locomotion similar like salemenders Limbs of other reptiles are elongated, slender, Remain close to body Many prehistoric reptiles were bipedal Walking on hind limbs is called bipedalism Heavy tail for balance

35. Temperature regulation Ectotherms Animals which use external heat source for thermoregulation are called ectotherms Endotherm Animals which generate internal heat during metabolism Some reptiles are endotherm like monitor lizard Brooding indian python

36. Heat regulation methods Reptiles regulate their body temperature by following methods Hibernation and aestivation some reptiles can survive in wide temperature fluctuation Body temperature are regulated within a narrow range between 25 and 3 C If they unable to maintain this range they move into retreat The body temperature remain within the range in this retreat

37. Behavioral methods of heat regulation Most thermoregulatory activities of reptiles are behavioral A lizard orient itself at right angle to the sun rays to warm itself It presses its body tightly on a warm surface to absorb heat by conduction A lizard orients its body erect prostrate to reduce conduction from warm surface Many reptiles are nocturnal in hot climate

38. Physiological method of heat regulation Some reptiles use panting for release heat Panting release heat through evaporative cooling Marine iguana absorb heat by basking in the sun It divert blood to the skin and warm up quickly Marine iguana reduce heart rate and blood flow to the skin during diving in the oceans It slows down heat loss Chormatophores also help in temperature regulation Dispersed chromatophores increase the rate of heat absorption

39. Heat regulation by torpor Many temperate reptiles withstand cold winter temperature by interring into torpor Torpor is an inactive stage The body temperature and metabolic rates decrease during torpor The body temperature of reptiles in torpor are not regulated It is different from true hibernation

40. Heat regulation by hibernacula The solitary reptiles migrate to a common site and spend winter there These animals clump together heat loss from these group is called hibernacula Exposed surface area reduced hibernacula Sometime, animals freeze and die in cooler winter Death from freezing is important cause of mortality for temperate reptiles

41. Difference between torpor and hibernation Some species enter a stage of sleep called “torpor” or “temporary hibernation” which is not as heavy as hibernation. Unlike hibernation, torpor is involuntary and lasts for just a few hours during the daytime Both food availability and outside temperature influence torpor

42. Support and movement Skeleton: Skelton is highly ossified thus provide greater support Skull Skull is longer than amphibians They have secondary palate Secondary palat separates the mouth cavity from nasal cavity They have longer snout It increase the sense of olfaction

43. Vertebrae Reptiles have more cervical vertebrae than amphibians The first two cervical vertebrae are atlas and axis Atlas articulate with single condoyle . It help in nodding Axis is modified for rotational movement They have different number of cervical vertebrae Ribs Ribs of snakes have muscular connection with large belly scales It helps in locomotion The cervical vertebrae of cobras are attached with some special ribs Cobra flares these ribs in aggressive displays

44. Autotomy The caudal vertebrae of many lizards possess a vertical fracture plane If a lizard is grasped by the tail, caudal vertebrae are broken Therefore a portion of tail is lost The loss of tail is called autotomy Autotomy is an adaptation that allow lizards to escape from predator Sometimes predator run away from lizard after seeing its broken moving tail The lizard later regenerates the lost portion of the tail

45. Circulation Two atrium Atrium are completely separated in adults Veins from body and lungs open into them The ventricle of most reptiles is incompletely divided The ventricle is completely divided only in crocodiles Pulmonary artery It take blood to the lungs Two systemic arteries One systemic artery arise from ventral side of heart One systemic artery arise from ventral side of heart It take blood to lower body and head

46. Circulation of blood The deoxygenated blood enters into the ventricle from right atrium It leaves the heart through pulmonary artery and moves to the lungs Pulmonary vein bring oxygenated blood from lungs and transfer it to left atrium Blood then enter into ventricle form

47. Gaseous exchange Larynx present Vocal cords absent Lungs

48. Excretion Excretory organ Kidney Terrestrial animals have large body size They have high metabolic rate Kidney is capable of processing wastes with little water loss Their kidney have many nephrons Most reptiles excrete uric acid It is non toxic and insoluble in water Uric acid is store in them in paste like form Non toxic uric acid can be stored in egg membranes Thus it has made possible the development of embryos in terrestrial environment

49. Osmoregulation There are many adaptation in reptiles to reduce water loss Their excretory system reabsorb water They have internal respiratory surfaces They have impermeable exposed surfaces The behavior that regulate temperature also conserve water Most reptiles are nocturnal When water is available they store large amount of water Many lizard possess salt glands below the eye, these glands remove excessive salts from the body

50. Reproduction and development Internal fertilization They have amniotic eggs It has adapted them completely independent of water

51. Nutrition and digestion Tongue Carnivorous The tongue of turtle and crocodile is non protrucible It helps in swallowing Some lizard and tuatara have sticky tongue Extended tongue of chameleon exceeds their body length

52. Modification in snakes for swallowing Skull is greatly modified for feeding Bones of jaw and skull are attached loosely These bones move away from each other for ingestion of prey Can ingest prey larger than head size Bones of upper jaw are moveable on the skull Attached loosely by ligaments at anterior end Therefore half of upper and lower jaw move independently Upper and lower jaw are moved forward and backward and retracted alternately after the capturing of prey Their teeth are posterior pointed These teeth prevent prey from escaping They also force the food into esophagus The glottis is much forward in snakes They can breath during swallowing of prey

53. Biting apparatus and biting mechanism Viper Viper possess hollow fangs These fangs present on maxillary bone at the anterior margin of upper jaw These fangs connected to venom gland The viper bites and inject venom When the snake mouth is closed fangs fold back and it lie along the upper jaw When moth open maxillary bone rotated fangs project outward Now viper strike object