Flashcards
Amphibian Flash Cards
Cards in this deck (12)
- 1TetrapodFour feet
Outgroup:
- Lungfish
Breathes air
Doesn’t have ‘arms’ like coelacanths
Is the ‘sister’ to tetrapod’s
- Coelacanths
White patches floress
Sleep vertically
Fleshy fins – start seeing tetrapod attributes > humerus - 2Moving onto LandTraces
- Tetrapod footprints found in rocks dated to 395 ma in Poland
Barriers to colonizing land
- Gravity – Water acts as support, on land the weight of the body must be supported by the limbs
Breathing – Gills collapse in air
Feeding – suction feeding does not work in air
So for animals to move onto land, the following are required:
- Supporting limbs
- lungs
- New behaviours… - 3Tetrapod Evolution- Eusthenopteron, ~385 Ma, aquatic
- Panderichthys, 380 Ma, bony fins.
- Tiktaalik, 375 Ma, ‘wrist’ bones – carpal bones
- Acanthostega, 365 Ma, 8 digits, weight bearing pelvic girdle and forelimbs
- Icthyostega, 374-359 Ma
Adaptations for locomotion on land
- Increasing articulation from Eustenpteron to Icthyostega to early Amphibian
- More rigid back - 4AmphibiansFirst tetrapods
Amphibian, from greek = ‘both kinds of life’ - 5Amphibian CharacteristicsCarnivorous / insectivorous
Papilla amphibiorum (sensory cells in ear)
Loss of posterior skull bones
Ectothermic
Amphibian skin
- Glandular and permeable – frogs often covered in mucus so glandular
- Respiratory gas exchange
- Blood vessels flow very close to surface
- Have lungs but when sat resting breath through skin
-Problems?
Intake toxic easily and skin can get clogged - 6Classification3 orders of amphibian
- Anura
(frogs and toads)
- Caudata
(salamanders and newts)
- Gymnophiona
(caecilians) - 7Classification Order: ANURA‘Without tail’
Frogs and toads
Rule of thumb: smooth skin = frog, warty skin = toad
Toads are a subgroup of frogs (bufonidae)
All toads are frogs but not all frogs are toads
45 families, ~5400 species
Most numerous group of amphibians
Found on all continents except Antarctica - 8Classification Order: ANURASIZE RANGE
- Biggest frog not very big compared to other animals (due to gas exchange > surface area : volume ratio
- Biggest: Goliath frog (Conraua goliath), ~30 cm
- Smallest: Paedophryne amanuensis, 7.7 mm
ENVIRONMENT
- Mostly moist environments
But…
- Fossorial – tree dwellers
- Desert rain frog – south Africa
Lives in burrow until it rains, sticks sand to body to reduce evaporation, nocturnal, no tadpole stage eggs hatch into miniature frogs
LOCOMOTION
- Unique to frogs and toads
- Large hind limbs and short forelimbs
- Some frogs cant jump
- Primitive frog
Landing head first – escape mechanism
Abdominal ribs and epipubic cartilage (spring)
- Derived frog
Derived frogs land with arms – not just for escape but for locomotion
Fused radius-ulna to withstand high for - 9Classification Order: CAUDATACaudata = ‘tail’
Salamanders and Newts
9 families, ~655 species
Lizard-like body morphology
Lateral undulation
Internal fertilisation
Metamorphosis
Extant forms often grouped as ‘Urodela’ - 10Classification Order: CAUDATAMETAMORPHOSIS
- Axolotl > salamander
Axolotl juvenile stage, some straight to salamander
PAEDOMOPHOSIS
- Retains juvenile features, but become sexually mature
DIVERSITY
- Pygmy salamander <2 cm in length
Giant salamander < 1.8m in length, 50kg (none that size now)
SALAMANDER FEEDING
Aquatic
Terrestrial
-Ballistic tounged salamander
Speed it retracts differs with temp
Going out is the same pace but when colder retracting is slower because already caught prey and saves energy - 11Classification Order: GYMNOPHIONA (CAECILIANS)‘Caecus’ = blind
10 families, <200 species
Live in the tropics
Limbless
Burrowing or aquatic
Large forms upto 1.5m in length
Suppercially similar to worms or snakes
Looks like an earthworm but isn’t – not real segments just folds
Surrounded by ring – shaped folds, making them look segmented
ADAPTATIONS
- Blind (or nearly blind)
- Diet not well known:
Hebrard et al 1992, (J. of Herpetology) found gut contents consisting mainly of unidentifiable organic matter
- Reproduction – Internal insemination
- Young eat shedded skin of mother
- Male has a ‘phallodeum’
- ~25% of speicies are oviparous, rest are viviparous - 12Amphibian DeclineAmphibians face serious declines, particularly since the 1980’s (most post-1500 extinctions occurred since 1980)
Current extinction rate may be 211 times background rate for amphibians*
- IF species in ‘imminent danger’ are counted as extinct, rate may be 25-45,000 times background extinction rate.*
The pathogenic fungus Batrachochytrium dendrobatidis, which causes Chytridiomycosis is responsible for major population declines.
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- Animal Diversity and Evolution (Amphibia ) Flashcards on Amphibian Flash Cards, created by Sarah Bell on 10/01/2018.
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- Sarah Bell
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