Chapter 11 Flashcards
Amniotic egg
an egg covered by a protective shell and containing a liquid-filled sac in which the embryo develops
Advantage allowed:
Elimination of free-swimming larvae
Eggs to be laid in dry place
Amnion
a liquid-filled sac that contains the developing embryo of some vertebrate animals
Yolk sac
a sac-like structure in amniotic eggs that contains a supply of food
Allantois
an embryonic support membrane that functions in elimination of wastes and is found in some vertebrates
Chorion
an embryonic support membrane that functions in gas exchange and is found in some vertebrates
Physiological Adaptations
Reptiles
Circulatory system more advanced than fishes
Fishes (gills, 2 chambered heart; 1A, 1V)
Reptiles (lungs, 3 chambered heart, 2A, 1V)
Osmoregulation adaptations:
Efficient kidneys
Salt gland
Desiccant-resistant
scales
Order Crocodilia
Crocodilia
Saltwater crocodile - Order of large reptiles – appeared 84 mya (late Cretaceous Period)
- Closest living relatives of birds; two known survivors of the Archosauria
The saltwater or estuarine crocodile (Crocodylus porosus) is the largest of all living reptiles
Marine habitats in Northern Australia, the eastern coast of India and parts of Southeast Asia
Order Chelonia
Chelonia
Sea Turtles
Evolved from terrestrial (land) turtles 150 MYA
Live and feed in the marine environment
Return to land to:
Lay eggs
Rest
Bask (thermoregulate)
Order Sqaumata
Sqaumata
Sea snakes & Marine iguana
Family Gavialidae – Gharials
Crocodila
Gharial (Gavialis gangeticus
Family Alligatoridae – Alligators & Caiman
Crocodila
American Alligator (Alligator mississippiensis)
Black Caiman (Melanosuchus niger)
Family Crocodylidae – Crocodiles
Crocodila
Saltwater crocodile (Crocodylus porosus)
Alligators:
Crocodila
Wider and shorter heads
U-shaped snout
Upper jaw wider than lower jaw
Teeth in lower jaw fit into depressions in upper jaw
Prefer freshwater
Crocodiles:
Crocodila
Narrow and longer head
V-shaped snout
Upper and lower jaws same width
Crocodiles better tolerate seawater due to salt glands
Saltwater Crocodile
Unlike other reptiles
Crocodila
Have a cerebral cortex, a 4-chambered heart, and functional equivalent of a diaphragm by incorporating muscles used for aquatic locomotion into respiration
Salt excretion- Crocodiles
Crocodila
Salt gland located in the mouth (modified salivary glands); salt is excreted through the tongue, spit out of the mouth
2 Families Sea Turtles
Chelonia
Cheloniidae & Dermochelyidae
Sea Turtle Marine Adaptions:
Chelonia
1) Lost capacity of tail undulation
2) Developed shortened, rigid body form & corselet (breastplate)
3) Modified limbs
Shell composed of two layers- Outer layer
Chelonia
composed of Keratin: a tough protein found in reptilian scales; called “scutes”
Shell composed of two layers- Inner layer
Chelonia
composed of bone; shell fused to vertebrae
Carapace
Chelonia
dorsal surface of a turtle’s shell
Plastron
ventral surface of the turtle’s shell
Chelonia mydas
Chelonia
Herbivore
Fibrilopapilloma tumors
Nest in NW Hawaiian Islands
Green sea turtle
Chelonia agassizii
Chelonia
Black sea turtle
Formerly subspecies of Green
Herbivore
Black pigmentation
Restricted to E. Pacific
Eretmocheyls imbricata
Chelonia
Hawksbill sea turtle
Spongivore
Shell highly prized; $100/lb
Until 1992 – 20 net tons/Japan
Nests on beaches of Hawaii
Lepidocheyls olivacea
Chelonia
Olive ridley sea turtle
Carnivore
Widely distributed in tropical waters
Found in Hawaiian waters
Rarely nests in Hawaii
Arribadas nesting
Arribadas nesting
Chelonia
females nest synchronously at the same time
Lepidocheyls kempi
Chelonia
Kemp’s ridley sea turtle
Carnivore
Restricted to Gulf of Mexico
Critically endangered
Arribadas nesting
Caretta caretta
Chelonia
Loggerhead sea turtle
Carnivore
Nests in S. Japan – only in N. Pacific
Prevalent in Gulf of Mexico and Atlantic
Natator depressus
Chelonia
Flatback sea turtle
Carnivore but ancestor of green sea turtle
Dorsal-ventrally flattened shell
Entire life cycle in coastal waters
Limited to Australia
Dermocheyls coriacea
Chelonia
Leatherback sea turtle
Carnivore;
Feeds exclusively on jellyfish
Flexible, tapered, & leathery carapace
5 distinct ridges, no scutes
Largest sea turtle; 500 kg
All turtles lack
Chelonia
teeth and have a beak-like structure to capture and secure prey
Nesting Occurs within 3 general constraints
Chelonia
- Nesting must occur during condition which are conducive to adult activity
- Nesting must occur during conditions that favor embryo development & survival
- Hatchlings must emerge into conditions that are conducive to their survival
Precopulatory behaviors
Chelonia
head bobbing, position in water column, head-head bumps, nuzzling, biting, movement of flipper, dinner
♂ mounts ♀, uses enlarged claws on fore & hind flippers to hold carapace
Curls long tail to bring cloacea into contact
In captivity coupled > 10hrs;
↑ Coupling = ↑ Fertility
Pattern contains
Chelonia
- Emerging from surf
- Ascending the beach
- Excavating the body pit
- Digging the egg chamber
- Oviposition (egg laying)
- Filling the egg chamber
- Filling the body pit
- Return to the sea
All species:
Chelonia
Lay several clutches during a nesting season
Lay white, spherical cleidoic eggs with flexible calcareous shells (50-130)
Size of eggs differs between clutches and among species
Size of eggs, # & # of clutches represent result of adaptive survival compromise
Sea turtle Hatching
Hatch after 6 – 13 weeks of incubation depending upon temperature
Weigh < 50% of oviposition weight
Large eggs produce large hatchlings
Sea turtle Hatchlings
Chelonia
Typically emerge at night – circumvent two major problems with diurnal emergence:
1. Lethal temperature
2. Predators
Hatchling Sex Determination
Chelonia
Temperature-dependent sex determination – produces ♀ at warm temps, ♂ at cool temps
Sensitive period for sex determination takes place during middle third of incubation
Less than 28°C - Primarily Males
Greater than 30°C – Primarily Females
Sea Turtles in Danger
Chelonia
Focus on conservation protection for reducing turtles divides into two categories:
1. Protection of the animals
2. Protection of their habitat
This requires:
1. Protection of eggs
2. Protection of nests
3. Protection of foraging areas
4. Protection of mating areas
Reptiles have a unique variety of organs used as salt glands
including
Chelonia
Sublingual glands – sea snakes
Lingual glands – crocodiles
Nasal glands – lizards
Lachrymal gland – sea turtles
2X size of leatherback brain
Reptilian salt glands:
Chelonia
When actived - discharges a fluid
6X that of blood; 2X seawater
When inactive – ¼ the concentrating capability
Greater than marine birds; 2X shark rectal gland
Unlike avian glands – remove Mg2+
Order Squamata
Squamata
Snakes evolved from lizards ≈ 135 mya
There are approximately 70 species of sea snakes living in our modern oceans
Account for 86% of marine reptile species
Classically 5 major groups of “sea snakes
Squamata-Sea snakes/kraits
Hydrophiids - ‘true’ sea snakes – 54 species
Laticaudids - sea kraits – 5 species
Acrochordids - file snakes – 3 species
Homalopsids - mangrove snakes – 9 species
Natricids - salt marsh snakes – 3 species
Subfamily Hydrophiinae
Squamata-Sea snakes/kraits
‘true’ sea snakes
The largest group of sea snakes
Evolved from Australian terrestrial elapids 30 MYA
Have the same toxic venom and envenomation Proteroglyphs have fixed front fangs like their terrestrial ancestors (mambas, cobras, adders)
Sea snakes – fully aquatic (never leaving the water) ovoviviparous (bear their young in the water) lack specialized ventral scales
Subfamily Laticaudinae
Squamata-Sea snakes/kraits
sea kraits
Comprise five species, four are marine
Are strongly banded and commonly seen in large numbers on beaches in south east Asia and some Pacific Islands
Sea kraits have also evolved from terrestrial elapids and are proteroglyphs with highly toxic venom
Are very placid and unlikely to bite unless provoked
Sea kraits are the only group of sea snakes that are oviparous (egg laying) and must return to land to breed
Sea kraits - amphibious (living on land and water), oviparous (returning to land to lay their eggs, have specialized ventral scales for crawling on land
Sea Snake Diving
Squamata-Sea snakes/kraits
Aerobic dives (O2) average 13 minutes & 20 meters
Anaerobic dives (No O2) increase time by 30-45 min 2 hr max depth
Ave > 50 m; 90 m max
One elongate cylindrical lung extends almost the entire body length for efficient for gas exchange
Are also able to carry out cutaneous respiration which is
Squamata-Sea snakes/kraits
Oxygen diffuses from sea water across the snake’s skin into tiny blood vessels and carbon dioxide diffuses out
Lecithinase
Squamata-Sea snakes/kraits
lysis of erythrocytes
Anticoagulase
Squamata-Sea snakes/kraits
delays or prevents blood coagulation
Hyaluronidase
Squamata-Sea snakes/kraits
leads to diffusion of venom into cells
Venom uses
Squamata-Sea snakes/kraits
Paralyzes prey; for defense
Not usually aggressive – many victims on shore
Salt Removal
Squamata-Sea snakes/kraits
Sea snakes avoid excess salt from sea water using a salt excreting gland, the posterior sublingual gland that sits under the tongue
Skin of sea snakes is very resistant to water, and does not let water in the snake easily
Hemipenes
Squamata-Sea snakes/kraits
paired penises found in snakes and lizards
Each is an autonomous independently functioning penis and only one is used during mating
Mating takes place for long periods and sea snakes must surface for air during that time
Subfamily Iguaninae
Squamata-Iguaninae
Marine, Fijian, Galapagos land, spinytail, rock, desert, green, and chuckwalla iguanas
Marine Iguana
Squamata-Iguaninae
Laterally flattened tail, dorsal spines allow for efficient swimming
Feed on marine algae
Remove salt via salt glands in nose
Marine Iguana reproduction
Squamata-Iguaninae
- ♀ lay 1-6 eggs in burrows dug 30-80cm deep - Eggs are laid in sand or volcanic ash up to 300m or more inland
- ♀ guard the burrow for several days then leave the eggs to finish incubation (95 days)
Marine Iguana diving
Squamata-Iguaninae
Can remain submerged for up to 60 min, though dives of 5 to 10 min are more common
Iguanas spend much of their time restoring body heat ( from cold water) by sunning themselves on the rocks adjacent the shore
Aves (Birds) can be defined as
Those advanced archosaurs with feathers
Those reptiles that fly
All reptiles closer to birds than to crocodiles
The last common ancestor of all the currently living birds and all of its descendants
Of almost 10,000 bird species, only about 300 are considered “marine”
Vertebrate Comparisons
Shore birds
Fishes – Poikilotherms, 2 chambers, Scales
Reptiles – Poikilotherms, 3 chambers, Scales
Birds – Homeotherms, 4 chambers, Feathers
Mammals – Homeotherms, 4 chambers, Hair
Shorebirds
Shore birds
Shorebirds (or waders) feed on the abundance of marine life in the intertidal zone
Range in size from a sparrow to a chicken
Exhibit a variety of bill and foot types
Both can dictate feeding life history
Bills dictate
Shore birds
type and size of prey
Feet and legs dictate
Shore birds
habitat birds can access
Haematopodidae
Shore birds
Oystercatchers
Use bills to slice, pry, and probe
Charadriidae
Shore birds
Plovers
Heavy body and short bill
Turnstones
Heavy body and slightly upturned bills
Scolopacidae
Shore birds
Sandpipers
Relatives plovers and oystercatchers; feed on crustaceans and molluscs
Pacific golden plover (Pluvialis fulva); Kolea
Curlews
Use long bills like forceps to extract shellfish
Avocets
Have long legs and use long upturned bills to sift side to side through the water
Stilts
Have extremely long legs and use long straight bill to probe mud for food (insects & crustaceans)
Hawaiian stilt (Himantopus mexicanus knudseni)
Family Ardeidae
Shore birds
Herons & Egrets
One of the most widespread families of wading birds; feed on small fish and crustaceans
crustaceans and molluscs
Cattle egret (Bubulcus ibis) & Black-crowned night heron (Nycticorax nycticorax)
Body type dictates
Seabirds
feeding strategy
Laridae
Seabirds
Gulls
are extremely vocal birds and are found in large groups
Are aggressive carnivorous feeders
Terns
Seabirds
are small graceful, seabirds with brightly colored and delicate bills
sub family Stercorariinae
Seabirds
Skuas
are very aggressive relatives of gulls; omnivorous and keen predators on other seabirds and eggs
Jaegers
are predators known for stealing fishes from terns and other seabirds
Subfamily Rychopinae
Seabirds
Skimmers
are small birds with 1) vertical pupils and 2) a flexible protruding lower jaw
Family Alcidae
Seabirds
Alcids(auks, puffins, and murres); similar looking to penguins but can fly and are more closely related to the gulls
Convergent Evolution
is an evolutionary process whereby similar selective pressures bring about similar adaptations in unrelated groups of animals
Ecological equivalents
are different groups of animals that have evolved independently along the same lines in similar habitats and therefore display similar adaptations
order Pelicaniformes
Seabirds
Pelicans and their relatives
are members of a group of birds that have webs between their four toes and many have a hooked upper mandible
Most are tropical or warm temperate and are well know fishers in open ocean and coastal habitats
Gular pouch
Seabirds
a sac of skin that hangs between the flexible bones of a pelican’s lower mandible
Sulidae
Seabirds
Boobies
dive from heights of 18-30m into the sea to catch their prey
Phalacrocoracidae
Seabirds
Cormorants
swim along the surface and dive for their prey; are excellent underwater swimmers. Lack oil glands to “waterproof” feathers - must “air dry”
Fregatidae
Seabirds
Frigatebirds
have lightweight bodies and very long wings; no oil glands so cannot land on water
Order Procellariiformes
Seabirds
Tubenoses
(petrels, albatrosses, shearwaters) have obvious tubular nostrils on their beaks
Better developed sense of smell and larger nasal glands
Stomachs contain a large gland that produces an oil composed of liquefied fat and vitamin A for feeding young
Procellariidae
Seabirds
Petrels
also called the “true” petrels and includes shearwaters and prions; migrate very long distances
Family Diomedeidae
Seabirds
Albatrosses
are the largest of any living bird and accomplished gliders; restricted range - rely on winds for flight
Family Hydrobatidae
Seabirds
Storm Petrels
small birds with long legs; erratic flyers with flapping wings and use feet paddling under the water
Order Sphenisciformes
Seabirds
Penguins
are the birds most adapted to life in the ocean; all live in Southern Hemisphere; only 2 species in Antarctica; densest feathers – used to trap air
