return to the ocean 1 Flashcards
Amphibian respiratory system
- amphibians : tetrapods with aquatic eggs
- permeable skin and gills
- lungs?
- simple sacs divided by ridges
- may simple supplement cutaneous respiration
- positive pressure breathing : buccal pump + elastic recoil
marine reptiles
successful in mesozoic :
- sauropterygians (plesiosaurs)
- ichthyopterygians
- mosasaurs
- sea turtles
< 70 extant species
- tropical/subtropical
- from 3 orders
Squamata (order)
snakes
- true sea snakes (~50 spp) fully marine
* ovoviviparity
- sea kraits (~5 spp) some terrestrial needs
* digestion on land
* ovoparity
- highly venomous
- coastal tropical, indian and pacific oceans
- excellent swimmers and divers
Iguana
- 1 sp (Galapagos)
Testudines (order) : turtles
- 8 spp:
- Green
- Black
- Flatback
- Loggerhead
- Hawksbill
- Olive Ridley
- Kemp’s Ridley
- Leatherback
- Distinguish spp. by head & shell
- Circumglobal, tropical
- Mainly coastal (except leatherback)
- Good swimmers: foreleg paddles
- Come ashore to lay eggs
Crocodylia (order)
2 species :
- crocodylus acutus (American crocodile)
- crocodylus porosus (saltwater crocodile)
reptile respiratory system
- Skin is nearly impermeable to O2
- But… cutaneous respiration in seasnakes
- Increased reliance on lung as
respiratory surface - Lung volume constant
- Subdivision increases
- Negative pressure breathing
(aspiration pump):- Uncouples feeding and breathing
- Requires thoracic cavity
- TIDAL VENTILATION
marine reptile adaptations
Cuticle impermeable, but…
* Salty foods
* Accidental ingestion of seawater
* Kidney cannot produce urine more concentrated than seawater
Salt glands- to excrete excess salt
* In marine lizards:
* On head
* Empties into nasal cavity
* Ridge prevents re-swallowing
* Sudden exhalation to expel
* In sea snake:
* Base of the tongue
* Empties into the oral cavity
* In turtles:
* In orbit of eye
* Empties into posterior corner of orbit
* In Crocodiles:
* Distributed over the surface of the tongue
Sphenisciformes (order)
( 17 spp )
Penguins
* All seabirds
* Southern hemisphere
* Flightless
* Feet -> rudder
* Wings -> fins
Procellariiformes (order)
( 125 spp )
* Albatrosses, petrels, storm-petrels, fulmars and shearwaters
* All seabirds
* Tubular nostrils
* Good sense of smell
pelecaniformes (order)
( 65 spp )
* Pelicans, frigatebirds, gannets, boobies, cormorants, anhingas
* All waterbirds
* All seabirds, except anhingas, some pelicans and some cormorants
* All four toes are webbed
* Salt gland enclosed within orbit
* Nostrils are slit like, nearly closed or absent
Charadriiformes
( 128 spp + ~ 200 shorebirds )
* Skuas, jaegers, gulls, terns, auks, guillemots, puffins, shorebirds & skimmers
* Mostly seabirds except shorebirds
Ciconiiformes (order)
- Herons, egrets, storks, ibis, spoonbills
- May feed along the shoreline, but not ‘seabirds’
lungs : the key to endothermy
- To be endothermic you must generate heat and keep it in
- That means you need to have insulation
- Insulated skin prevents gas exchange
- Can’t be bimodal: lungs need to be efficient at CO2
elimination AND O2 uptake - Having efficient lungs is vital for evolution of endotherms
seabirds : adaptations to life at sea 1
Energy management
* Weight reducing adaptations
* High MR and endothermy
* Specialised lungs
Salt management
* Feed in salt water
* May avoid saltwater ingestion
* Nasal salt glands- above eye
* Connects to nasal cavity
* Preening gland / waterproofing
seabirds : adaptations to life at sea 2
Locomotion and feeding
* Wings for:
* Underwater swimming
* E.g. penguins, cormorants
* Flying vast distances
* E.g. albatrosses
* Flying fast and agile, close to shore
* E.g. auks and puffins
* Bodies can be streamlined for swimming underwater
* Webbed feet
* Bills adapted to prey type and feeding mechanism
Colouration
* Can be cryptic… or not
