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Reptiles Scientists believe other land vertebrates evolved from BONY LOBE-FINNED fish 310 million years ago… reptiles were the first vertebrates to make the complete transition to life on land • an increase in competition for food and space among all the life-forms in aquatic environments • limited competition for the insects and plants that could be used as food on the land Adaptations to Land • Waterproof Skin dry body covering of horny scales or plates – develops as surface cells fill w/ keratin - same stuff as bird feathers and fingernails – prevent water loss (lipids and proteins) – protect from wear and tear associated w/ living in rugged terrestrial environments, keeps out germs – unlike amphibians who can’t be far from water or they’ll dry out External Structural Adaptations (for land)• some limbs have toes • • w/ claws – permit to climb, dig, and move in various terrains others have toes modified into suctions cups – aid in climbing absence of limbs – snakes use scaly skin and highly developed skeletal and muscular systems TURTLE EXTERNAL ANATOMY Nictitating membrane Tympanic membrane External nares Only reptiles with NO TEETH NAME THE MEMBRANES Red arrow = ? Nictitating membrane Function= ? Protect eyes; “Swim goggles” Green arrow = ? Tympanic membrane Function =? eardrum Limbs at right angles to body Location of Pelvic and Pectoral girdles allow turtle to pull limbs into shell http://www.biosci.ohio-state.edu/~eeob/anatomy/eeob512/miscellaneous/turtleskeleton.jpg Claws on feet SHELL IS LIVING PART OF BODY Expanded ribs form shell Can regenerate damaged scutes Growth rings tell age The small segments on a turtle’s shell are called ______________ scutes This part of the shell that covers the Dorsal surface is the _____________ carapace This part of the shell on the ventral surface is the plastron _______________ This side part that connects the upper and lower shells is the Bridge _________________ CURVE OF PLASTRON MALE PLASTRON slightly CONCAVE to fit on top of female FEMALE PLASTRON slightly CONVEX to make more room for eggs Image by Riedell/Vanderwal©2005 This part of the shell is the bridge ________ plastron It connects the ___________ carapace and ________________ TURTLE INTERNAL ANATOMY TURTLE LATIN meaning ANIMALIA KINGDOM _____________ PHYLUM ____________________________ CHORDATA “backbone” SUBPHYLUM VERTEBRATA ___________________________ REPTILIA “to creep or crawl” CLASS _______________________________ CHELONIA “tortoise” ORDER _____________________________ NERVOUS • COMPLEX BRAIN • DORSAL SPINAL CORD (Spine is fused to shell) • Cranium (skull bone) • Nerves connecting to spinal cord and brain Nervous Cont. • Cerebellum –Controls balance & motor coordination • Medulla oblongata • Controls involuntary organs • Cerebrum • Controls higher thinking and learning Nervous Cont. • Tympanic membrane – Eardrum • Bone connecting eardrum to inner ear: columella • Olfactory lobe – Smell • Optic lobes – Processes info about vision • Jacobson’s organ – Sense organ for smell in roof of mouth of snakes & lizards TURTLE BRAIN BIGGER CEREBRUM than same sized amphibian Image modified from: http://theturtlepages.crosswinds.net/anatomy/reprodexc.html ENDOCRINE Glands that make hormones that control other body organs PANCREAS controls blood sugar levels THYROID: located above heart Makes hormones that control heart rate, blood pressure; cell development and growth Respiration • Well developed lungs (not gills) – tissues involved in gas exchange area located inside body - kept moist in even driest environmen ts INTERNAL NARES (connects to External nares “nostrils”) PHARYNX GULLET GLOTTIS (Opening to lungs ) Tell one thing you could look for to tell which of these tubes is the trachea and which is the esophagus? Look for the cartilage rings. That’s the trachea, air tube that connects the larynx to the lungs. BRONCHI • Two tubes that connect the lungs with the trachea • Carry air. This is the _____g_ lun gg Image by Riedell/Vanderwal©2005 Its function is Gas exchange • Fills lungs by expanding rib cage. • Pressure reduced within thorax draws in air. LUNGS HAVE ALVEOLI TURTLE LUNG Increase surface area for more gas exchange Images modified from: http://www.stclement.pvt.k12.il.us/studentWeb/science98/GarrittPatM/alveoli.gif Circulation • like amphibians have double circulation • most have 3 chambered heart • partial division of ventricle separates oxygen-poor blood flowing from the body from the oxygen-rich blood returning from the lungs • alligators and crocodiles have 4 chambered hearts – separation of oxygenated and deoxygenated blood TURTLE HEART 3 CHAMBERS 2 atria; 1 ventricle Image from: BIODIDAC PARTIAL SEPTUM: begins to divide ventricle into two sides Sinus Venosus & Conus Arteriosus are smaller Circulation • Right atrium: Receives blood from sinus venosus • carries only LOW oxygen blood • Left atrium: Receives blood #1 #2 from lungs • carries only HIGH oxygen blood • Sinus venosus: Receives #3 deoxygenated blood from body (smaller) • Conus arteriosus:sends oxygenated blood to organs and deoxygenated blood to lungs. (smaller) • Ventricle: pumps blood out of the heart • Carries both high and low oxygen blood Circulation • Veins carry deoxygenated blood to the heart. • Arteries carry away oxygenated blood from the heart. – Pulmonary artery can be constricted so blood bypasses lungs to warm body quickly! • Capillaries carry oxygenated blood that will diffuse into organs. Single Loop: Fish Double Loop: Amphibians & Reptiles Sinus venosus Lungs RIGHT LEFT Atrium Atrium Ventricle Body organs Conus arteriosus FROG/TURTLE CIRCULATION SPLEEN Make, store, recycle RBC’s Digestive System Vent Image from: http://theturtlepages.crosswinds.net/anatomy/index.html Image from: http://www.spc.cc.tx.us/biology/jmckinney/Studyimages/turtle/turtledissectlist.html This tube is the _______________ esophagus It carries __________ food stomach to the ___________ STOMACH Add ACID; Start DIGESTION; Grind & mash food SMALL INTESTINE Duodenum Ileum LARGE INTESTINE (Also called COLON) Name this part of the tube duodenum Give a function Add trypsin,bile Finish digestion Absorb nutrients Image by Riedell/Vanderwal©2005 Pink arrow = ? ____________ Ileum (SI) Function = ? ______________ Finish digestion Absorb nutrients Image by Riedell/Vanderwal©2005 Red arrow = ? Large intestine ____________ Give a function Collect/ concentrate digestive waste Also called the COLON Image by Riedell/Vanderwal©2005 LIVER Makes BILE Stores GLYCOGEN Stores VITAMINS Processes TOXINS including nitrogen waste for kidneys GALL BLADDER Stores BILE PANCREAS In mesentery near first loop of small intestine Makes TRYPSIN, INSULIN, GLUCAGON Image by Riedell/Vanderwal©2005 cloaca Red arrow = ? Name the body systems that empty here Excretory, digestive, reproductive MESENTERY This membrane that holds the digestive organs in place This exit opening is the vent __________ Name the body systems that use this exit Digestive, excretory, & reproductive __________________ WHAT SEX IS IT? FEMALES: Short tail Vent closer MALES: Longer tail Vent farther from body Images modified from: http://theturtlepages.crosswinds.net/anatomy/index.html REPRODUCTIVE Vent Vent MALE FEMALE OVARY• make eggs OVIDUCT• add shells • transport to cloaca EPIDIDYMIS –sperm mature here; add tails TESTES – make sperm Image from: BIODIDAC INTERNAL FERTILIZATION Increases chances of sperm and egg meeting Image from: http://www.turtletimes.com/PhotoContest/2001PhotoContests/May2001/Geoemyda%20spengleri%20mating.jpg SEX is determined by TEMPERATURE of NEST Image from: http://www.parcplace.org/documents/GeneralHerpInfo/learnabout2.htm Types of Reproduction Ways offspring enter world OVIPARITY- Reproductive tract encloses egg in a protective shell Eggs deposited outside body to hatch Nourishment comes from egg EX: Most reptiles,birds & a few mammals (monotremes) Ways offspring enter world VIVIPARITYNo shell around egg Eggs retained in body Nourished by mother through placenta Offspring are born alive Ex: Mammals & some reptiles Ways offspring enter world OVOVIVIPARITYEgg surrounded by protective shell but kept in body until just before hatching or can hatch inside female Nourishment comes from egg not mother Ex: Some reptiles (snakes) OVI PARITY SHELL? NO SHELL? Embryo grows? Food comes From? Seen in? SHELL OUTSIDE EGG Birds, Reptiles, Few mammals OVOVIVI PARITY SHELL INSIDE VIVI PARITY NO SHELL INSIDE EGG MOTHER Reptiles Mammals, few reptiles Amniote Egg • an egg with a protective membrane and a porous shell enclosing the developing embryo. -It forms a “nursery” to protect the embryo - The egg derives its name from the amnion, the thin membrane enclosing the salty fluid in which the embryo floats. • They yolk sac encloses the yolk, a protein rich food supply for the developing embryo • The allantois stores the nitrogenous wastes produced by the embryo until the egg hatches • The chorion lines the outer shell and thus encloses the embryo and all the other membranes. It regulates the exchange of oxygen and carbon dioxide between the egg and the outside environment. • The entire amniote egg is surrounded by a leathery shell that may be hard in some species because of the presence of calcium carbonate. -The egg is water proof, however it allows gases to flow between the environment and the chorion. • The male places the sperm inside the female before the shell is formed. This is called internal fertilization, makes water transport of sperm unnecessary. DIRECT DEVELOPMENT Image from: http://www.neuroscientist.com/animimag/turtles.htm Excretion • conserve water by excreting nitrogenous wastes in dry or pasty form as crystals of uric acid Blue arrow = ? kidney Function ? Excrete nitrogen waste (make urine) osmoregulation Image by Riedell/Vanderwal©2005 Image by Riedell/Vanderwal©2005 The red arrow = ? ______________ Urinary bladder Give a function Store urine Name the form of nitrogen waste excreted by reptiles Uric acid Temperature Regulation • • • • metabolism rate controlled in part by body temperature Ectothermic (cold-blooded) – body temp controlled by environment not endothermic (warmblooded) regulate their temp by behavior – bask in sun to speed up metabolism – hide in shade to prevent overheating ECTOTHERMIC ADVANTAGES: Slow metabolism means you can survive on 1/10 the food as a same size endotherm DISADVANTAGES: • Can’t to live in extremely cold places (NO reptiles in Arctic) • Can’t keep up max activity level for long Origin and Evolution • From the studies of fossils and comparative anatomy, biologists infer that reptiles arose from a group of ancestral reptiles called cotylosaurs, which lived about 310 million years ago. - Fossils indicate that these fourlegged, sprawling vertebrates resembled small lizards and had teeth used for eating insects -The abundance of insects at the time may have been one reason the cotylosaurs flourished. • during the Permian period these reptiles began to adapt to other available environments, giving rise to new forms of reptiles. - These groups included flying reptiles called pterosaurs • - Two groups of marine reptiles: the ichthyosaurs and plesiosaurs • - And the thecodonts • • • • • The dominant land reptiles came from the thecodonts. - The small lizard-like carnivores, many of which walked on their hind legs. The thecodonts were the first archosaurs ( “ruling reptiles”), a group that later included the early crocodiles, the dinosaurs, and the reptiles that evolved into birds. The Mesozoic era is known as the Age of Reptiles. - During this time reptiles , esp. the dinosaurs, dominated all other forms of life. - Dinosaur means “terrible lizard” however many of the dinosaurs were small. Yet the incredible size of some dinosaurs distinguish the group from all other forms of life. -One of the largest dinosaurs was the brachiosaurus, 77,00 kg. It was as long as a tennis court, as tall as a four-story building, and heavier than elephants. • • • • Over 300 genera of dinosaurs have been identified around the world. -They were adapted to a wide range of environments. Brachiosaurus and such related dinosaurs as Diplodocus and Apatosaurus were herbivores, plant eaters. - They probably used their long necks to reach the top of trees. Tyrannosaurus and other carnivores, or meat eaters, walked on their hind legs and used sharp teeth and huge claws to rip apart prey. The scientist who studies dinosaurs are known as Paleontologists. Modern Reptiles • Reptiles are classified into 16 orders, 12 that are extinct. - 4 surviving-6, 000 species • Reptiles occur worldwide except in coldest regions - Human intervention-major impact • 4 living orders of Class Reptilia: - 1. Rhynchocephalia, - 2. Chelonia, - 3. Crocodilia, - 4. Squamata Rhynochocephalia • Only living speciesSphenodon punctatus- the tuatara - Inhibit islands of coast of New Zealand - Resembles a large lizard about 60 cm long - Has an inconspicuous third eye on top of its head- parietal eyefunctions as a thermostatprotects from overheating - Active at low temperatures and feed at night on insects, worms and small animals Chelonia • Order consists of about 265 species of turtles and tortoises - Tortoise are terrestrial Chelonia (Galapagos tortoises) - Turtles- chelonians that live in water - Body covered by a shell made of hard plates- 2 parts- a carapace and plastron - Shape is modified for variety of ecological demands - retract heads, swimming - Forelimbs of a marine turtle have evolved into flippers and freshwater turtles have webbed toes - Migratory behavior of sea and river turtles -return to land to lay eggs Crocodilia • Order composed of 20 species of large lizardshaped reptiles- crocodiles, alligators, caimans and gavials - Descendants of archosaurs • Crocodilians live in or near water in tropical/ subtropical regions of the world • - Crocodiles- nocturnal animals; Africa, Asia and Americas • - Alligators - China and southern U.S. - Caimans- Central America- some in Florida - Gavials- eat fish; long and slender snout- live only in Burma and India • Carnivorous- hunt by stealthfeatures adapted for this behavior - Eyes on head, nostrils on top of snout -see and breathe while in water - Valve to prevent water from entering air passage - Parental care- both parents care for young by carrying in jaws until development Squamata • Order consists of 5,640 species of lizards and snakes - Loosely jointed upper jaw and paired reproductive organs in males - Structurally diverse • Lizards- presence of limbs • - Common lizards- iguanas, chameleons, skinks and geckos - Live everywhere except Antarctic - Special adaptationsagility and camouflage - 2 species are venomousGila monster (SW U.S.) and beaded lizard (western Mexico) - Most prey on insects or - Blend with background - chameleons- remain inconspicuous and fend off enemies - Horned lizards- spiked armor, when disturbed they inflate themselves, gape, hiss and squirt blood from eyes - Skinks and geckos- lose their tails and regenerate- autotomyescape from predators - Most lizards are small- .3m in length; iguanas- 1m in length - Largest lizards- monitorsKomodo dragon (Indonesia) 3m (9.8 ft) in length, 140 kg (308.6 lbs) - Thought to be related to snakes - have a forked tongue for sense organs - Consume prey whole and use tail as defense weapon Adaptations of Snakes Snakes probably evolved from lizards that lived above ground found during the Cretaceous period. Movement • A snake has a backbone of 100 to 400 vertebrae, each of which has a pair of ribs attached. - Providing the framework for thousands of muscles • The interaction of bones, muscles, and skin enables asnake to move in one of three basic ways: 1. Lateral undulation 2. rectilinear movement 3. side winding. Movement cont. • Most commonly move by lateral undulation. - moving forward in an S shaped path. • In rectilinear movement, the snake applies muscular force on its belly, not its sides. - Scutes are scales on its belly that catch on bark orother rough surfaces (like a caterpillar). • Some desert-dwellers snakes progress by side-winding. Feeding • Snakes eat animals, but lack structural adaptations common to other carnivores. • Snakes do not see or hear well, and have no limbs, and their teeth and small mouth cannot rip and grind flesh. Locating Prey • Snakes evolved a sense of smell which they use to locate their prey. - By flicking its forked tongue , a snake gathers chemicals from the environment. • The tongue transfers these chemicals to two pits in the roof of the mouth called the Jacobsons organ where the nerves are highly sensitive to the chemicals. Locating Prey Cont. • Some snakes inject their prey with Toxic venom • most bite down their fangs and inject the poison into their prey. • Venom is chemically complex. - The hemotoxins are proteins that attack the circulator system, destroy red blood cells and disrupt the clotting power of blood. - The neurotoxins work on the nervous system, by disrupting the nerve pathways which is dangerous to respiratory and heart functions. Swallowing and Digesting Prey • A snakes upper and lower jaws are hinged and move independently. • when unhinged, the jaws stretch to allow the mouth to open extremely wide. • While swallowing it whole the snake thrusts its windpipe into the throat, allowing the snake to breathe - the process of can take several hours. Defense • Natural selection resulted in modifications for defense. • Camouflage is beneficial for both seeking prey and hiding from predators. - many snakes are green and blend with foliage - others are brown and hide against the bark of trees Defense Cont. • Some snakes defend themselves by signaling their presence. • Some ward off danger by rapidly changing body shape - extending a hood like cobras • Some hiss • Others make mechanical noises - such as the rattle of the rattlesnake. Reproduction • Most male snakes rely on the scent of female snakes of heir own species. • Before mating, a male and female snake may glide alongside by side, with the male stroking the female with his chin and flicking his tongue over her body. • Fertilization is internal. Reproduction cont. • Most snakes are oviparous - female lays eggs that hatch outside her body. - To break out a hatchling uses a special tooth which is lost soon after. • Other snakes are ovoviviparous - the female carries the eggs in her body throughout development • the young are born live. - All newborns must fend for themselves, relying on their many specialized adaptations for survival on land.
