Download Phylum Chordata: Subphylum Vertebrata: Class Amphibia

Class Amphibia
Courtney Connolly
In Phylum Chordata: Subphylum Vertebrata
Includes 3 subclasses
1. Labryinthodontia (extinct) 2. Lepospondyli (extinct) 3. Subclass Lissamphibia (recent
species) – has all the living organisms
1. Caudata (urodela) = salamanders
2. Anura (salientia) = frogs, toads
3. Apoda (gymnophiona) = caecilians
Amphibia = “double life” (terrestrial and aquatic)
Batrachology = the study of amphibians
General Information
Habitat
• For the most part, live in freshwater bodies of water (e.g. streams, lakes, etc)
• Warm climates, need moisture to prevent desiccation
• Do not live in extreme climates (like Antarctica or Arctic)
Feeding Mechanisms
 Vary based on stage of life and order
o Diet usually includes insects, mollusks, worms, small reptiles and amphibians
o Ex: frog larvae herbivorous, frog adult carnivorous
 Most use some kind of adaptation with a sticky tongue, strong jaw, or sharp teeth (or
combination of multiple or all three)
Types of Reproduction
• Most need freshwater for reproduction
• Could be external or internal
• Egg -> aquatic hatchling (gills for breathing), larvae stage (10 days – 20 or more years)
• most are oviparous (will lay eggs) – 100s of eggs, lay in body of water or puddle on a leaf
• most larvae are herbivorous (but some omnivores and carnivores)
• success usually depends on rainfall quality and timing (seasonal)
Unique Characteristics
• metamorphosis (gills vs lung breathing)
o have lungs for land, gills for water-life
• Tetrapods (have 4 limbs which evolved from pectoral and pelvic fins)
• For the most part, glandular, soft skin -> mostly live in warm climates, need moisture
o O2 can diffuse through skin (can “breathe through it”)
o makes them sensitive to environmental changes, may act as “canary in a coal mine” with
climate change and pollution
o No scales (except caecilians) but skin can be rough/bumpy
• Ectotherms – no regulation of body temp.
• 3-chambered heart, 2 atria, 1 ventricle – double circulation like humans
o pulmonary and systemic blood mix
• bony endoskeleton
Caudata/Urodela
Salamanders, Newts
“bearing a tail” – in all stages of development
four equal-sized limbs, long body, smooth skin (can have mucus/poison glands)
470 species, 10 families
Habitat
• Soil or aquatic environment (some all aquatic but most follow pattern of larvae=aquatic,
adult=terrestrial) -> ponds, streams, lakes, rivers, swamps, grasslands, and wet mountain forests
• Terrestrial species live under rocks and logs daytime, feed during nighttime
• Aquatic species live under stones or at bottom of bodies of water
• All continents (just not Antarctica or Australia)
Feeding Mechanisms
• Not herbivores, all carnivores with sharp teeth, long tongue (can extend it quickly and food sticks
to the tongue), and jaw (can catch prey with jaw and teeth by moving toward it and grabbing it)
o Most salamanders have teeth but not all have adapted tongue (ex: aquatic
salamander species)
o eat slow-moving creatures (earthworms, snails, slugs, fish, small mammals)
• Diet: arthropods, worms, small mollusks
Types of Reproduction
• External fertilization (sirens and giant salamanders)
o Female releases eggs, then males fertilize in water
• Internal fertilization (salamanders and newts)
o female takes in male spermatophore/ “sperm pack” (used by 90% of salamanders)
• can follow many possible egg/larvae development ways (ex: both egg and larval stages are
aquatic, eggs are terrestrial while larvae aquatic, both terrestrial, eggs in oviduct then birth, etc)
• mate during winter, lay eggs (2-50,000+) -> in ponds or under rocks, leaves, etc.
• breeding once a year or once every two years
• most hatch from eggs (salamanders can lay up to 450 eggs, newts lay up to 400 eggs) wrap
body/leaves around eggs to protect them
Unique Characteristics
• Little differences between genders (males have hedonic glands, rougher skin)
• Includes families: Cryptobranchidae (hellbenders, largest living salamanders), Ambystomatidae
(mole salamanders), Amphiumidae (congo eels), Plethodontidae (lungless salamanders),
Necturidae/Proteidae (mudpuppies), Salamandridae (newts), Sirenidae (sirens)
• Means of respiration: skin, external gills (when young & then disappear), lungs (except
plethodontids)
• Narrow head: small eyes
• no ears but some species can pick up sound vibrations with body
• Skin differences (Newts: dry warty skin) vs (Salamanders: smooth, slick skin)
• Brightly colored skin = poisonous, glands on back of neck/tail secrete poisonous or non-tasty
substance, + other behavioral adaptations
Anura
Frogs and Toads
About 4750 species, 28 families
Four unequal-sized limbs
Habitat
• some live only in water, otherwise moist environment
• found in many places (just not Antarctica, Arctic, or Greenland – no deserts or polar areas)
• during winter cold, enter sleep (torpor) and natural antifreeze in body
• desert and dry season, survive by estivating (dig themselves into mud until it rains)
Feeding Mechanism
• Herbivorous larvae
• Carnivorous adult
o Eat insects, spiders, slugs, worms, possibly small rodents or reptiles/amphibians
o Maxillary teeth along upper jaw to grind up food (weak and cannot be used for
obtaining food)
o Use sticky, coiled tongue to catch food (attached to mandibles in the front, “free at the
back”)
o Eyeballs can curl back into head; at same time tongue pushes up -> this crushes the
food in between and helps the frogs get the food down their throat
Types of Reproduction
• External fertilization – eggs/sperm in water
• Males use vocalization (attracts mates and warn rivals)
• Amplexus – male clasps female
• Two positions: axillary (male clasps female behind forelimbs) and inguinal (male clasps female
around waist)
• Tadpoles -> metamorphosis (within 24 hours – gill pouch disappears, front legs emerge, eyes
move to high up on skull + eyelids, skin glands created and thickened, eardrum grows, adapts
nervous and digestive system) -> adults
• Some species, the male puts eggs on back and moves them to a moist, safe place
Unique Characteristics
• Various families, including Ascaphidae (tailed frog), Pelobatidae (spadefoot toads),
Leptodactylidae (narrow-toed toads), Bufonidae (true toads), Hylidae (tree frogs), Ranidae (true
frogs), Myrohylidae (narrow-mouthed toads)
• Moist skin has dermal layer – mucus and poison glands
• Special skeletal and muscular arrangement to accommodate strength needed for jumping and
swimming (skull a little lighter)
o Strong back legs, short/rigid backbone, lack ribs
• Respiration ways: skin, lungs
o Forces air down into lungs and “pushes it out”
• Large eyes for sight
• Varying colors; bright colors signal potential predators that it is toxic and poisonous; green/brown
for camouflage
• Toads = puff up to look bigger for protection
Apoda/Gymnophiona
Caecilians, Legless
“without legs”
considered “subterranean diggers”
about 176 species, 6 families
Habitat
• Tropics & subtropics (South America, Africa, and Southeast Asia)
• Central Africa, SE Asia, southern Mexico to Argentina
• Like ground soil and litter; tropical forests
• Also like streams
Feeding Mechanism
• Eat plankton when in larvae stage
• Sharp teeth (2 rows top and 1-2 rows bottom) – eat mollusks, small snakes, frogs, lizards,
worms, and other caecilians (swallow whole or in large chunks)
Types of Reproduction
• Internal fertilization – male puts sperm in female
o Eggs laid (30-60) in moist soil near water -> hatch larvae -> metamorphosis -> adults
o OR eggs laid -> metamorphosis -> hatch as adults
o OR live birth (2-25) (eggs inside female for 9-11 months, then hatch)
o Yolk sac = supports initial fetus development, then uterine milk = feeds embryos
Unique Characteristics
• Long legless body
• Skin/bone can cover eyes
• Retractable head tentacle = sensory organ (No need for hearing or seeing so no ears and very
tiny/hidden eyes)
o only amphibians that have tentacles
• Vertebral column (95-285 vertebrae) + ribs
• Shiny ringed skin folds = annuli – looks segmented but is not
• Pointy skull to enhance burrowing
• most have one lung
• gets all O2 through skin and mouth
Sources:
http://www.shsu.edu/~bio_mlt/AMPHIBIA.html
http://www.angelfire.com/mo2/animals1/amphibian/amphibia.html
http://www.d.umn.edu/biology/courses/bio3701/Amphibia.htm
http://www.ucmp.berkeley.edu/vertebrates/tetrapods/amphiblh.html
http://en.wikipedia.org/wiki/Amphibian
http://en.wikipedia.org/wiki/Caecilian
http://en.wikipedia.org/wiki/Frogs
http://en.wikipedia.org/wiki/Salamanders - Feeding
http://www.sandiegozoo.org/animalbytes/t-caecilian.html
http://www.sandiegozoo.org/animalbytes/t-salamander.html
http://www.sandiegozoo.org/animalbytes/t-frog_toad.html
References
Snedden, R. (2008). Living Things: Amphibians (P. Morgan, Ed.). North Mankato, MN: Smart Apple
Media.
Wilkes, S. (2006). World Almanac Library of the Animal Kingdom: Amphibians (P. Goodman, Ed.).
Milwaukee, WI: World Almanac Library.