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97 Cards in this Set
- Front
- Back
Why did limbs evolve?
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Fishes evolved in times of drought, had to move between ponds
They needed to walk around on the bottom of lakes and ponds Crawled on shores to escap predators Many underutilized ecological niches |
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How did limbs evolve?
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ugh...
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Why did these animals leave the comforts of the aquatic environment
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A likely explanation is that these animals were forced to crawl across land to escape ponds that were drying out and shrinking
Competeing theory- early vertebrates ventured increasingly onto land in pursuit of insect prey |
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Early tetrapod changes
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Loss of several cranial bones, the skull was rigidly linked to shoulder girdle by several bones that disappeared early in the evolution of terrestrial vertebrates
This allowed for a mobile neck Allowing the head to remain relatively stable while walking |
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How do early tetrapods adapt to gravity without water
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Sacral rib connecting the axial skeleton (the spine) the the pelvic girdle (the hip)
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Lepospondyli
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Early in amphibian evolution
"spool-shaped" vertebral centra forms from direct ossification of the notocord |
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Labyrinthodontia
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"Labyrinth-teeth"
Vertebral central formed from leurocentra and intercentra - cartilaginous precursors Ichthyostegida- "first" amphibians |
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Notocord amphiban changes
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REduction of notochord and a rigid spine
Vertebral centra of osteolepiforms are thin and surround the notochord (persists in most tetra pods as the intervertebral disks) without constricting it greatly A shorter notochord that does not exten into the braincase |
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Presacral vs postsacral
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vertebrae before vs vertebrae after the pelvis
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Tetrapod soft parts vocab
Parathyroid glands |
controls level of blood calcium
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Tetrapod soft parts vocab
Harderian gland |
Located anterior to the eye
secrets oily liquid that lubricates the eye |
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Vomeronasal organ
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Olfactory organ located in the palate
Used to smell food in the mouth |
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Tetrapod soft parts
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Layer of dead cells that reduces water loss- present in amniotes and in most lissamphibians
Well0developed muscular tongue with glands Loss of internal gills |
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Problems of life on land
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Gravity
Locomotion Different modes of senses dryness Respiring Temperature |
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Solutions to life on lands
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Gravity- Stronger skeletal system, development of more complex muscular arrangment
Locomation- shifting from swimming to crawling Dryness- mucous glands to moisten skin, then water proof barriers, i.e. keratinized tissues, scales Respiring- refinement of lung as a respiratory structure Temp- ability to maintain higher , constant body temperature |
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Lissamphibian synapomorphies
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Moist, permeable skin that allows for cutaneous (of or relating to the skin) gas exchange
Papilla amphibiorum- a sensory area in the wall of the sacculus of the inner ear, sensitive to sound frequencies below 1000Hz |
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Papilla amphibiorum
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A sensory area in the wall of the sacculus of the inner ear, sensitive to sound frequencies below 1000hz
Lissamphibian synamorphies |
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Operculum-plectrum complex
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Bones involved in the transmitting of sounds to the inner ear
Pectrum columella is derived from the hyoid arch Columella and plectrum are fused in anurans, caecilians and in some salamanders Lissamphibian synapomorphies |
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Green rods
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retinal cells unique to amphibians
seen in caudates and anurans, but not caecilians (may be related to reduced eyes) |
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Pedicellate teeth
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Crown and base or pedicel of teeth composed of dentine, seperated by a zone of uncalcified dentine made of fibrous connective tissue
Lissamphibian synampomorphies |
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Levator bulbi
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thin muscle in the floor of the orbit
Innervated by the 5th cranial nerve, that causes the eye to bulge outward and to enlarge the buccal cavity Present in anurans and urodeles and in a modified form in caecilians Lissamphibian synapomorphies |
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Orders within Lissamphibia
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Proanura- ancestral frog-like group
Anura- Frogs and toads Caudata- Salamanders Gymnophiona - caecilians (legless, wormlike amphibians) |
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Amphibian skin Epidermis
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Keratinzed specialization
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Amphibian Aquatic Adult skin
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Thin layer, 1-2 cell layers only, low in waxes
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Amphibian Terrestrial Adult skin
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Thickness increases relative to adaptation to terrestrial/dry environment
Some have more waxes/phospholipids and produce less mucus making dry skin (toads) |
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Osmoregulation of Amphibia
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Epidermal glands
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Epidermal glands Functions
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Aestivation (hibernation)- some drought adapted frogs build mucous cocoons
Protect skin from bacteria and parasites Aids cutaneous (through the skin) respiration (it requires a moist skin, though) |
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Epidermal glands functions continued
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Phermonal- attract mates in some salamander
Poisonous or sticky - deter predators, often buy not always widespread over body |
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Keratinised caps
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Amphibian skin specialization
On fingertips, may be sharp used by frogs and slamanders in fast fresh water streams to grasp ground |
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Tubercles
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Amphibian skin specialization
Thick keratinized pads on front thumbs Used by males for holding females during mating common in frogs and salamanders |
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Spade
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Amphibian skin specialization
Blade-like structure on rear feet for digging |
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Salamander reproduction
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Return to water (some breed on land i.e. plethodon)
Usually ponds without fish (toxic species can breed with fishes) Courtship and sperm transfer - spermatophore, spermatheca Lay eggs in gelatinous masses, possibly a symbiotic algae relationship |
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spermatophore
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a capsule or mass created by males of various animal species, containing spermatozoa and transferred in entirety to the female's ovipore during copulation.
used by salamanders |
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Spermatheca
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receives and stores sperm from the male or, in the case of hermaphrodites, the male component of the body, and can sometimes be the site of fertilization when the oocytes are sufficiently developed.
Salamanders |
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Describe the Juvenile stage of salamanders
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Small gilled version of adult
Exrternal gills functional early Swim to surface to gulp air as they near metamorphosis Carnivorous - feed on aquatic insectrs and macroinvertebrates, some cannibalistic |
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Describe the pond type salamander larvae
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Larger gills
Larger tail fins |
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Describe the stream type salamander larvae
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Smaller gills -reduces drag
Smaller tail fins |
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Describe mountain brook type salamander larvae
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Smallest gills
no tail fins more muscular appendages |
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Describe Anuran reproduction ritual
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Males vocalize to attract female
Males grab females for breeding (amplexus) Either Auxillary amplexus (male grabs female around armpits) or Inguinal amplexus (male grabs female around waist) Most with external fertilization |
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Lecithotrophy
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Reproductive specialization in amphibians
All nutrients for development to hatching contained in yolk of egg |
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Matrotrophy
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Reproductive specialization in amphibians
Some of the nutrients provided by female during gestation Oophagy- egg feeding, young feed on eggs in oviduct Adelphophagy - uterine cannibalism, developing young eat on siblings in oviduct Histophagy- developing embryos feed on maternal secretions histotrophy- developing embryos absorv maternal secretions Placentotrophy- developiong embryos receive nutrients from the mother by placental transfer |
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Oophagy
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- egg feeding, young feed on eggs in oviduct
Salamandra atra |
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Adelphophagy
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- uterine cannibalism, developing young eat on siblings in oviduct
salamander altra |
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Histophagy
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- developing embryos feed on maternal secretions
Ceacilians, salamanders and frogs |
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histotrophy
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- developing embryos absorv maternal secretions
Typhlonectes |
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Placentotrophy
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- developiong embryos receive nutrients from the mother by placental transfer
(not found in amphibians but in reptiles.... ooh) |
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Patrotrophy
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Father provides nutrients to developing young
Rhinoderma darwinii - tadpoles in vocal sacs |
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Important reptilian evolutionary advances
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Cleidoic egg
Stored water, food, gas exchange structures, protective function of shell Keratinised epidermal scales are waterproof |
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Synapsida
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– reptilian skull, inferior temporal fenestra only
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Euryapsida
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– reptilian skull, superior temporal fenestra only
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Anapsida
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reptilian skulls, no temporal openings,
found in turtles and related fossil forms |
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Subclass: Anapsida
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orders Cotylosauria (stem reptiles) and Testudinata (turtles) – hard shell (carapace of fused, expanded ribs, ribs positioned outside girdles, horny beak (no teeth)
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Subclass: Diapsida
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Two temporal openings on each side of skull
Squamata Crocodilia Pterosauria - winged reptiles Ornithischia - dinosaurs with bird-like pelvis Plesiodaurs Ithyosaurs Saurischia - dinosaurs with reptile-like pelvis |
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Subclass: Synapsida (one temporal opening on each side)
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Order: Therapsida - precursor to mammals
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Commonalities between reptiles and birds skull
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Share common eature of a completely ossified skull and openings (fenestrae) of the outer dermatocranium in the temporal region
Diapsida: superior and inferior temporal fenetrae, above and below the postorpial squamosal bar Condition in squamate and birds is highly modified Lower arch is lost in squamates and in snakes the postorbital bar is also lost |
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Differences in reptile and bird skulls
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Reptiles the dermatocranium tends to be haevier than that of birds, which is thinner and has air spaces
Birds have more highly developed vision, which results in reinforcement of the eyeball with a ring of bones (sclerotic bones) that ring the orbit but do not articulate with it ( a condition seen in many dinosaurs) Birds tend to have larger brain-to-body size ratios, requiring increased braincase size Birds have modification of the jaws into a peak with loss of teeth |
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Dermatocranium
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The skull roof, or the roofing bones of the skull are a set of bones covering the brain, eyes and nostrils in bony fishes and all land living vertebrates.
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Sclerotic bones
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Ring of bones around the eyeball of birds to provide structural reinforcement
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Saurischian vs ornithischian hipbones
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Saurischian are more round and detached ischium and pubis bones, while ornithischian are straighter and the ischium and pubis bones run parralel diagonally together
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Reptile skin development
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Cells more highly keratinzed, create scales
Snakes the scales are modified into scutes used for locomotion Turtles scales modifided into plates to cover shell |
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Describe the design of reptilian epidermis
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Dermal papilla stimulates localized outgrowth of epidermis into scales
Specialized stratum corneum that is compact, very thin and very hard Scales clightly lither on exposed surface Hinge of scale is thinner "ruffled" to allow bending of the body More heavily keratinized than amphibians Skin is dry, no mucous glands |
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Describe the chemical composition of reptilian skin
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Typically B keratin and A keratin, in some combination
B keratin is harder that a keratin Added lipids aid water proofing in some taxa |
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Turtle skin variation from common reptilian skin
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Non-overlapping scales cover bony shells - B keratin
New keratinized scales are added in layers, wear off slowly Desert tortoise legs Exposed portion - B kertatin Hinge region - a keratin Pattern a and B keratin varies among more aquatic taxa |
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Archosauria
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-are a group of diapsid amniotes whose living representatives consist of birds and crocodilians. This group also includes all extinct dinosaurs, extinct crocodilian relatives, and pterosaurs.
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Archosauria skin composition
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Exposed portion - B Keratin
Hinge region - a Keratin New keratinized scles added in layers ( older scales wear off slowly) |
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Lepidosauria
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reptiles with overlapping scales. This subclass includes Squamata and Rhynchocephalia. It is a monophyletic group and therefore contains all descendents of a common ancestor. The squamata includes snakes, lizards, and amphisbaenia
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Lepidosauria skin composition
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Several unique, derived design features
Keratin pattern unique- exposed portion, 2 layers with top (B keratin) and deep (a keratin), and hinge region, 2 layers with top (B keratin) and deeper (a keratin) Scales are more highly overlapping and thin than other "reptiles" Old stratum corneum shed nearly simultaneously (single units in snakes) |
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A reptilian invention that has to do with the hand?!?!?!?
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Claws!
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Function of reptilian claws
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Aid locomotion on land
Grasp prey Defense |
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Chemical composition of claws
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Keratinized with calcium salts for added strength
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Turtles, crocodiles and lizard respiratory system
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Paired lungs
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Snakes respiratory system
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Most species with single lung -right (limitations of a cylindrical body form
Ancestral groups with two lungs - right is larger (boas and pythons) Protrusable glottis allows for breathing during swallowing of large prey |
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glottis
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Protrusable glottis allows for breathing during swallowing of large prey
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cutaneous
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-of, relating to, or affecting the skin.
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Mechanoreceptors
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Special nerve endings that give information about the body condition (pain, temperature receptors, pressure tension)
Cutaneous receptors. reptilian sensory structures |
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Labial pits
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Jump to: navigation, search
A python (top) and rattlesnake illustrating the positions of the pit organs. Arrows pointing to the pit organs are red; a black arrow points to the nostril. The ability to sense infrared thermal radiation evolved independently in several different families of snakes. Essentially, it allows these animals to "see"[1] radiant heat Similar in strucutre and funcition Many pits in seris of labial scales Boas and pythons - boaidae and pythonidae |
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Loreal pits
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Infrared detection
"pit" vipers - crotalidae , with one pair of pits |
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Columella
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articulates with tympanic membrane in turtles, crocodilians, and lizards.
articulates with quadrate bone in snakes. the bony or partly cartilaginous rod connecting the tympanic membrane with the internal ear in birds and in many reptiles and amphibians |
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Quadrate/artocular jaw articulation
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vibrations transmitted through jaw elements to quadrate. best at 200-500hz.
These bones shift to become incus and malleus of mammals. |
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Vision: diurnal species of turtles
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good color vision
rods and cones oil droplets for greater range of wavelength detection. |
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Vision: good color vision but basically nightblind
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diurnal lizards and colubrid snakes with only rods
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vision: accomodation
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increase in intra-vitreous pressure pushes lens forward.
ciliary muscles contract to flatten lens (not in snakes) |
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secondary palate
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an anatomical structure that divides the nasal cavity from the oral cavity.
partially developed in turtles. more developed in crocodilians. |
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vomeronasal organ (VNO)
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olfactory epithelium in the roof of the mouth of lizards and especially developed in snakes.
tongue delivers chemical particles to the VNO tongue flickering indicates chemical sensing sensory input from this structure leads to olfactory (terminal) nerve and olfactory bulbs. |
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homodont
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(in reptiles) all teeth morphologically similar.
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heterodont
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differentiation of teeth into morphological types (canines, molars, incisors)
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monophyodont
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single set of teeth throughout life of animal
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polyphyodont
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continuous tooth replacement
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serpentine undulation
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typical slithering.
vertical surface to generate forward thrust |
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concertina locomotion
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movement in burrow or tube
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rectilinear locomotion
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caterpillar-type motion.
pairs of dermal/costal muscles used to move ventral scutes and ribs |
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sidewinding locomotion
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for movement on loose substrates, sand.
loops of the body lifted and thrown forward. |
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acrodont
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teeth held to leading edge of bone (tuatara)
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pleurodont
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teeth held on inside edge of bone (some lizards)
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thecodont
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teeth set into sockets (crocodilians)
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Amphibian ventiliation
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Glotis
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opening to lungs,can be extended by some snakes to go outside of the mouth while eating prey
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