chapter 19-amphibians amphibian- double life - water and land
TRANSCRIPT
Chapter 19-Amphibians
Amphibian- “Double Life”
- Water and land
Amphibian Characteristics 1st true tetrapod vertebrates Bony skeletons with four limbs
– Exceptions: Caecilians (limbless) and Sirens (forelimbs only) Many w/webbed feet Thin moist skin; no scales Breathe w/ lungs lungs (Internal, bag-like organ that exchanges oxygen
and carbon dioxide with the air and blood)– Exception: Lungless salamanders– Larvae- gills
Cutaneous respirationCutaneous respiration- “Skin breathing”– Supplement oxygen intake w/ moist skin– Limited by body size
Double-Loop Circulation
Amphibian Characteristics
Partially divided heart: – Atrium separated into left and right sides by septumseptum,
ventricle is not– Right side sends oxygen-poor blood to lungs– Left side send oxygen-rich blood to organs
Double-loop circulationDouble-loop circulation:– Two large veins (pulmonary veins) return oxygen-rich
blood from lungs to heart– Blood pumped to tissues at higher pressure than fish– Systemic circulation- Blood flow to the body
Class Amphibia
Order Anura- Frogs and toads Order Urodela (Caudata) – Salamanders,
sirens, newts, waterdogs, mudpuppies Order Gymnophiona (Apoda)- Caecilians
Class Amphibia
Order Anura- Frogs and Toads Anura- without a tail Adult carnivores Skin with mucus and some with
poison glands Sticky tongue, hinged at the front,
attaches to prey– Vomerine teeth- two small nobs
help hold in prey Hind legs adapted for jumping Frogs are smooth w/ longer legs Toads are rough w/shorter legs
Most frogs depend on water for life cycle– Females lay eggs in water– Males fertilize them – Larvae are tadpolestadpoles
• Gills • Feed on algae• Incomplete
metamorphosis• Develop into adult
frogs• Rate depends on species
and food
Leopard Frog and Fowler’s Toad
Goliath Frog- Conraua goliath
- Largest frog in world- Found in Cameroon
Poison-Dart Frogs- Family Dendrobatidae
Frog Characteristics Tympanic membraneTympanic membrane- thin
membrane that detects vibration (eardrum)– Eustachian tubes- equalize
pressure on eardrums
Skin has mucus glands– Mucus is poisonous or foul
tasting in most
Nictitating membrane- transparent eyelid
Two teeth in roof of mouth Swallow food whole
CloacaCloaca- Chamber opening to outside of body– Serves as exit for wastes and
gametes
- Oviduct- carries eggs to cloaca- Vocal Sacs- Expandable membranes
that collect air after passing over vocal cords for louder croaking
Amplexus
Order Urodela (Caudata- with a tail) 369 species of salamanders, newts,
sirens, amphiuma, waterdogs, and mudpuppies
Elongated bodies w/long tails Smooth, moist skin; Require moisture External fertilization in water or
moist area– Internal fertilization- females
insert sperm packet into cloaca– Larvae gilled, carnivorous,
smaller version of adult– Some retain gills as adults
(neoteny- never lose larval characteristics)
Salamanders
Axolotl
Salamander that never loses its gills
Neoteny Found in N.
america
Other Urodela (Caudata)Newt
Amphiuma
Water dog
Mud puppy
Order Caudata- Sirens
Aquatic salamanders Have only front
extremities Maintain gills
throughout life Some can vocalize Most likely external
fertilization
Order Apoda- Caecilians
Apoda- without legs Tropical, burrowing
amphibians Small, bony scales
embedded in skin Legless Carnivorous Male deposits sperm directly
into female Females may have live
young or lay eggs