Class Amphibia (Chapter 30.3)

Class Amphibia (Chapter 30.3)Please set up your notebook for Cornell Notes

What is an amphibian?Characteristics

Vertebrates, generally live in water as larva and land as an adult Breathes with lungs as an adult and has moist skin

Form and FunctionFeeding

Larva typically filter feeders or herbivoresAdults carnivorousDigestive tract mouth, esophagus, stomach, intestines, cloaca

Cloaca muscular cavity through which urine, poop, egg and sperm leave the body

RespirationLarva – most use skin and gillsAdults – gills are replaced with lungs although some gas exchange occurs through skin

CirculationDouble Loop

First loop carries oxygen poor blood from heart to lungs and skinSecond loop carries oxygen rich blood from heart to body and oxygen poor blood from body to heart

Heart – 3 chambersRight atrium gets oxygen poor blood from bodyLeft atrium gets oxygen rich blood from skin and lungsVentricle gets blood from both atria, then pumps to body

Blood from each ventricle is mixed

ExcretionAmphibians have kidneys to filter waste from blood

Urine is transported from kidneys to cloaca by thin tubes called ureters

ReproductionMost amphibians have external fertilization

Eggs do not have shells and must be kept moist; laid in or near water

MovementLarva move like fishAdults walk, hop, run, or jump

ResponseSimilar brain to fishWell developed nervous and sensory systemsEyes have protective membrane called nictitating membraneTympanic membrane eardrums, located on side of headsHave lateral line systems

Orders of AmphibiansOrder Caudata (Urodela) salamanders and newts

Carnivorous both as adults and larvaAdults live in moist places like under logs and rocksSome salamanders have gills all their life and live in water (mud puppy)Some salamanders do not have lungs and rely on gas exchange through skin

Order Anura frogs and toadsNo tail as adultsFrogs

Leap, have smooth, moist skinToads

Hop, have warty, drier skin

Order Apoda – CaeciliansLegless animals that live in water and burrow in moist soilMany have fish like scales embedded in skin