Amniotes  amniota-turtles – lepidosaurs – archosaurs & mammalsAnamniotes-Non amniote vertebratesinclude majority of fishes & all amphibiansAmniotes – dispensed w/ larval stage – can not lay eggs in waterAmniote Traits1. Amniotic egg – egg w/ elaborate extraembryonic membranes surrounded by a shell2. Impermeable skin – have a much thicker epidermis, w/ elaborate keratinous structures (scales, feathers & hair) * high levels of lipids in epidermis3. Costal ventilation of lungs – have an advanced method of lung ventilation thatinvolves the rib cage4. Temporal Fenestration – skulls characterized by FENestra (openings) vary b/w groups (3 diff conditions)a. Anapsid conditioni. No fenestraii. Early amniotes & turtlesb. Synapsid conditioni. Single fenestra behind orbitii. Synapsids ( mammals & mamml like rep’s)c. Diapsid conditioni. 2 fenestae behind orbitii. Lepidosaurs (lizards snakes) & archosaurs (crocs dinos & birds)Differences b/w anamniotic & amniotic eggShell – provides mechanical protection but is porous enough to allow movement of resp. gases & water vapor-*fluid filled membanes also give mechanical protectionShells can be soft & flexible or hardAmniotic has 3 additional extraembryonic membranes-amnion-extraembryonic membrane – only surrounds embryo-Cavity formed b/w embryo & amnion is called Amniotic Cavity (filled w/ amniotic fluid)-Chorion-Extraembryonic membrane – surrounds other extraembryonic memberanes-Outermost MemBrane-Allantois-Develops as an extension of the hind gut-Acts as a storage area for N waste produced by metab. Of embryoBase of allantois contributes to formation of urinary bladder as adult-Highly vascularized & serves as a respiratory organ during later development- Left behind upon hatchingADVantage of Amniotic Egg-allows amniotes to dispense w/ the larval stage & have larger offspring upon hatch-strong correlation b/w egg size & adult sizeAmniote skin epidermis -typically thicker than amphibians-less vascularized (no subcutaneous resp)-lesser diversity of glands-Keratin – type of fiberous structural protein (sclera-protein) – contain large amounts of S – mature keratin is dead- In great abundance in amniote skin (though present in all craniates)- Outermost layer Stratum Corneum – composed of dead keratin rich cellsKeratinous structures-derived from epidermis----possible b/c skin is not involved in repiration-armor of earlier vertebrates derived from DERMIS-some amniotes have dermal armorLung Ventilation-Costal – Rib cage expands & contracts lungs-Tidal Flow – expansion of rib cage = Negative pressure, draws air into lungs via trachea -contraction of rib cage forces air back outAmphibians had buccal pump to force air into lungs - relied heavily on throat muscles- more energy consuming than costal ventilationSynapsids vs SauropsidsDiff methods of lung ventilation-Synapsids – plesiomorphic tidal flow – air flows in & out of lungs through same passage known as – ALVEOLAR LUNG-Derived Sauropsids birds & poss dino’s evolved through system where air flow 1 direction FAVEOLAR LUNGRead chapter 11Section. 11.2Pages 274-279(not the text