Flashcards
Lecture 9 vertebrates
Cards in this deck (12)
- 1What are Urodela?Newts and Salamanders. Typically 4 limbs and short bodies with long tail.
Reduced skull bones
No external ears
Most require water for breeding;
Internal fertilization (via spermatophores) in most.
Larval stage essentially has same body form as adults. - 2What are Gymnophiona?They are Caecilians.Elongate, burrowing or aquatic amphibians
Reduced or absent tails, no limbs and girdles
Reduced eyes
Reduced/absent left lung
Skull well ossified with fused bones, with teeth
Unique jaw adduction musclature.
A unique sensory organ, the tentacle, present
Internal fertilization in all spp., with phallodeum.
c. 25% of spp. viviparous
Very little is known about natural history. - 3What are Anura?Frogs and toads. Reduced skeleton especially skull and backbone
Hind limbs greatly elongated, some limb bones fused
Tongue attached at front of mouth,
Larvae lack true teeth
Larvae have very different body form to adults (tadpoles)
Metamorphosis involves radical reorganization
Very variable reproductive modes and life histories
Controversial molecular taxonomy - 4What are Chelonia?Body encased in shell, limb girdles within rib cage
Teeth replaced by keratinous beak.
Plastron may be solid or hinged.
Limb structure very variable.
All are oviparous, with no parental care.
Males have intromittent organ
Very long-lived
Variable sex determination mechanisms
2 major extant clades, Pleurodira & Cryptodira
Shell (dorsal carapace and ventral plastron joined laterally by bridge, incorporates ribs, most of vertebrae (except tail and neck), and part of pectoral girdle. No movement in axial skeleton and cannot breathe using rib movements. courtship can be elaborate. - 5What are Crocodylia?Body elongated, long snouts and powerful tails
Skin heavily armoured with osteoderms
Swim with lateral undulations of tail and body
Transparent membrane covers eye when u/w.
Nostrils dorsally and terminally located, valvular.
Muscular diaphragm, lungs well-developed alveoli
Oviparous with internal fertilization
Temperature-dependent sex determination. - 6What are Rhynchocephalia?Essentially unchanged from Triassic
Share some characters with lizards and snakes (superorder Lepidosauria, “scaly lizards”)
Have teeth on palatine bones.
Adults have a pair of chisel-like bony outgrowths at front of jaws.
No intromittent organ.
Lower temporal bar present in skull - 7What are Squamata?Snakes. Highly kinetic (flexible) skulls compared to other reptiles
Paired, copulatory organs (hemipenes)
Skin covered with scales
Caudal autotomy (voluntary tail loss)
Sex determination mechanisms variable
Parthenogenesis occurs (more widely than previously realized)
Ideal model for evolutionary studies - 8What are Amphisbaenians?Fossorial and mostly limbless
Limbless, elongate, relatively small
Reduced or absent limb girdles
Heavily ossified and modified skulls
Bodies are annulated
- 2 segments per vertebra
Skin can usually move independently
of trunk
Tails usually v. short
Reduced right lung
Most are oviparous. - 9What is the heart structure of amphibians and turtles?3-chambered. But 3-chambered separate in turtles.
- 10Describe respiration in Frogs?
- 11What is special about amphibians skin?amphibians have a unique kind of permeable skin. Both oxygen and water are allowed to pass in and out of the delicate integument in order that homeostasis and a sufficient level of respiration may be maintained at all times, even when the animal is underwater. The skin of amphibians is also unusual because it must be kept in a relatively moist to help draw oxygen through the skin.
- 12How do amphibians maintain their moisture?In order to sustain the necessary moisture level, amphibians secrete mucus via glands contained in the skin. This mucous chiefly serves as a protective layer around the body when the animal is on land, but also facilitates a proper salt and water balance within the internal organs when the amphibian is submerged in water
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- Flashcards on Lecture 9 vertebrates, created by bsu2d5 on 04/01/2015.
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