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Reptile 6S (13) Lee Michelle Ching Yin Me too! We are reptiles! Class: Retilia General features: • live on ground, while some can live in water as well • poikilotherm • most are carnivorous, except turtles are herbivorous • breathe with lungs • skin covered with scales/ scutes • lay shelled eggs • tetrapods Body Structure •have lungs - crocodiles: muscular diaphragm increase space for greater lung inflation •have horny epidermis watertight able to live on dry land •exposed parts protected by scales & scutes •have three-chambered heart - 2 atria, 1 ventricle, 2 aortas - deoxygenated blood can be shunted back to the heart and oxygenated blood can be shunted back to the lungs more effective thermoregulation longer diving time diurnal animals -vision can adapt daylight condition -with colour vision -more advanced vision depth •some snakes have heat-sensitive pits sense the body heat of birds and mammals hunt in the dark •lack a secondary palate - must hold their breathe while swallowing - except crocodiles & skinks - snakes: extend their trachea and stick out like a fleshly straw •camouflage -skin colour is usually grey, brown or green blend into the background of the natural environment avoid confrontation Reproduction •most reptiles reproduce sexually • all reproductive activities occur through the cloaca • most reptiles have copulatory organs, which are usually retracted or inverted and stored inside the body •some squamates (lizards & snakes) are able to have asexual reproduction • parthenogenesis • females are able to produce a unisexual diploid clone of the mother •oviparous -most reptiles lay eggs covered with leathery or calcareous shells •ovoviviparous/ viviparous - ovoviviparous= embryos develop inside eggs, without placenta - viviparous= birth of offspring without the development of calcified eggs - evolved only in lizards & snakes • temperature-dependent sex determination - the incubation temperature determines whether a particular egg hatches as male or female - most common in turtles and crocodiles - sometimes occur in lizards and tuataras as well Defense Mechanism snakes • crawl away into the underground • hiss loudly • vibrate the tip of the tail ( rattlesnakes) • elevate the head and spread out the skin of the neck to look bigger and more threatening • use venom to attack • play dead crocodiles • expose the teeth and yellow tongue • plunge into water and sink out of sight • hiss loudly • inflate the body to look bigger • chase • bite lizards • the tail has more vivid colour • when captured by the tail shed the part of the tail • detached tail will continue to wiggle •the tail can be regenerated Reptiles dry & scaly skin with claws breathe with lungs eggs have thick, hard shell eggs laid in buried, insulated nests external fertilization do not have larval stage Amphibians moist & sticky skin without claws breathe with lungs & gills eggs without protective outing covering eggs laid in water / damp places internal fertilization pass through larval stage before metamorphose into adult form The End! Reference: http://en.wikipedia.org/wiki/Reptile http://en.wikipedia.org/wiki/Tempe raturedependent_sex_determination http://en.wikipedia.org/wiki/Parthe nogenesis
