B8 vertebrates Flashcards
amphibian respiratory system
Permeable skin and gills, lungs are simple sacs divided by ridges (many simply supplement cutaneous respiration).
Positive pressure breathing (buccal pump and elastic recoil).
circulation separation
To survive low O2 water. Atrium fully divided, ventricle functionally divided, oxygenated blood meant reduced gills, systematic blood = gills, then lungs.
Amphibian circulation
Left side of heart gets blood from lungs, then flows back through to right side of lungs. Issue with myocardial hypoxia so there is a cutaneous artery which provides extra O2 to right side of the heart.
marine reptiles
Successful in Mesozoic (Squamata, testudines, crocodylia). Sauropterygians (plesiosaurs), ichthyopterygians, mosasaurs, sea turtles. <70 extant species, tropical/subtropical (from 3 orders)
Order Squamata (56 species)
scaly reptiles/snakes
True sea snakes (50 species), fully marine, ovoviviparity (incubate eggs, give birth to life young). Sea kraits (5 species), some terrestrial needs (digestion on land, ovoparity = lay eggs on land). Highly venomous, swim/dive. Coastal tropical, Indian and pacific oceans. Iguana, 1 species in Galapagos.
Order Testudines (7 species)
Distinguished by head and shell, circumglobal, tend to be tropical/coastal. Good swimmers (foreleg paddle), lay eggs on shore
Order Crocodylia (2 species)
Crocodylus acutus (American crocodile)
Crocodylus porosus (Saltwater crocodile)
Reptile respiratory system
-Skin nearly impermeable to O2 (but cutaneous resp in sea snakes (through skin))
-Increased resilience on lung as resp surface
-Lung vol constant, subdivision increases
-Negative pressure breathing (aspiration pump, expand muscles around lung cavity which inflates a ballon making negative pressure to draw air in, this means a mouth muscle isn’t required for breathing (thorax muscle, so can breathe and eat at the same time), uncouples feeding and breathing, requires thoracic cavity.
-Tidal ventilation (they have to change direction of fluid, may be dead spaces, but at least they are breathing air.
Circulation in a turtle
-Atria are completely divided, ventricles are partially divided (just like in amphibia).
-They can have a double, systemic, or pulmonary circulatory system.
-This means they can do a right to left shunt (blood flows from the body, gets shoved from right to left, and goes back to the body, without every going across the lungs). This is because they need to save energy and save the oxygen too. It is shunted because they switch off their pulmonary vessels.
Marine reptile adaptations
-good swimmers and divers, cutaneous respiration ((sea snakes) don’t become anaerobic despite 2hr dives)
-lung extends full length of body, posterior portion oxygen store
-small/thin scales and flattened body.
-cuticle is impermeable (but may accidentally ingest seawater, salty foods, and kidney can’t produce urine more concentrated than seawater so they use salt glands).
Salt glands in marine lizards
Salt glands on head, empties into nasal cavity, ridge prevents re-swallowing, sudden exhalation to expel.
In sea snakes = base of the tongue, empties into oral cavity.
In turtles = in orbit of eye, empties into posterior corner of orbit (looks like crying).
In crocodiles = distributed over the surface of the tongue
Order Sphenisciformes (17 species)
Penguins, all seabirds. Southern hemisphere (other than Galapagos) , flightless. Feet = rudder, wings = fins
Order Procellariiformes (125 species)
Albatrosses, petrels, storm-petrels, fulmars, shearwaters, all seabirds. Tubular nostrils, good smell
Order Pelecaniformes (65 species)
Pelican, frigatebirds, gannets, boobies, cormorants, anhingas, all waterbirds. All seabirds, some pelicans and some cormorants. All four toes are webbed. Salt gland enclosed within the orbit. Nostrils are slit-like, nearly closed or absent.
Order Charadriiformes (128 species + *200 shorebirds)
Skuas, jaegers, gulls, terns, auks, guillemots, puffins, shorebirds, skimmers. Mostly seabirds except shorebirds.
