120 likes | 1.26k Views
Chapter 28.3 – Class: AMPHIBIA I. Characteristics A. Thin, moist skin for breathing thru it: cutaneous respiration B. Most have 4 legs C. Most live on land – but water is required due to external fertilization: 1. water is needed as a medium to transport sperm
E N D
Chapter 28.3 – Class: AMPHIBIA I. Characteristics A. Thin, moist skin for breathing thru it: cutaneous respiration B. Most have 4 legs C. Most live on land – but water is required due to external fertilization: 1. water is needed as a medium to transport sperm 2. eggs lack protective membranes & a shell – they would dry out on land
D. Ectotherm – an animal that has a variable temperature; heat is from its environment 1. Body reactions require specific temperatures, so amphibians are dormant in very hot & cold seasons E. Metamorphosis 1. Aquatic larvae have gills, tail fin, & a 2-chambered heart 2. Adults breathe thru skin, have poorly developed lungs, & a 3-chambered heart
F. 3 chambered heart – this heart provides enough O2 to the body’s cells, since walking on land requires more energy and O2 than swimming 1. 1st chamber receives O2-rich blood from the lungs & skin skin must be moist to exchange O2 2. 2nd chamber receives O2-poor blood from the body tissues 3. 3rd chamber pumps O2-rich blood to body tissues & O2-poor blood to lungs & skin
II. Diversity of Amphibians A. Order ANURA: frogs & toads w/ no tails 1. Predators that eat insects & worms 2. Vocal cords produce sounds to attract a mate 3. Low #s of frogs or frogs w/ deformities may signal pollutants
4-toed Salamander Red-backed Salamander B. Order CAUDATA: salamanders & newts 1. long, slender body w/ neck & tail 2. resemble lizards, but they lack claws & their skin is smooth & moist Central Newt – toxic! Tiger Salamander
C. Order APODA: caecilians 1. limbless w/ a short or no tail 2. found in the tropics & are often blind 3. internal fertilization