Class – Amphibia

GENERAL CHARACTERISTICS:

• Name Ori­gin: Derived from Greek words “Amphi” (dual) and “bios” (life), reflect­ing their abil­i­ty to live in both aquat­ic and ter­res­tri­al habi­tats.
• Habi­tat: Inhab­it both aquat­ic and ter­res­tri­al envi­ron­ments.
• Limbs: Most pos­sess two pairs of limbs.
• Body Divi­sion: Body is divid­ed into head and trunk.
• Tail: Tail may or may not be present.
• Skin: Moist skin, lack­ing scales.
• Eyes: Eyes have eye­lids.
• Ears: Tym­pa­num rep­re­sents the ear.
• Cloa­ca: Ali­men­ta­ry canal, uri­nary, and repro­duc­tive tracts open into a com­mon cham­ber called the cloa­ca, which opens to the exte­ri­or.
• PHYSIOLOGICAL CHARACTERISTICS:
• Res­pi­ra­tion: Res­pi­ra­tion occurs through gills, lungs, and skin.
• Heart: Three-cham­bered heart (two auri­cles and one ven­tri­cle).
• Body Tem­per­a­ture: Cold-blood­ed (poik­ilo­ther­mic).
• REPRODUCTION AND DEVELOPMENT:
• Sex­es: Sep­a­rate sex­es.
• Fer­til­iza­tion: Exter­nal fer­til­iza­tion.
• Repro­duc­tive Mode: Oviparous (egg-lay­ing).
• Devel­op­ment: Indi­rect devel­op­ment (lar­val stage present).
• Exam­ples: Bufo (Toad), Rana (Frog), Hyla (Tree frog), Sala­man­dra (Sala­man­der), Ichthyophis (Limb­less amphib­ian)