Origin and Ancestory of Amphibia || Zoology

Origin and Ancestory of Amphibia
Earliest Amphibia:

Labyrinthodontia because of the folded nature of dentine of their teeth.
They probably originated 300 million years ago, during Devonian period and flourished through Carboniferous and Permian periods before extinction in Triassic.

Adaptations to amphibious life:
Locomotion- Streamlined body retained for swimming.
Skeleton- Vertebral column becomes more rigid.
Pectoral girdle lost connection with skull.
Pelvic girdle attached to vertebral column and two halves firmly united.

Muscles- Stronger muscles to lift body above ground.
Respiration- Gills replaced by lungs for gaseous exchange in air.
Cutaneous respiration supplements pulmonary respiration.

Circulatory system- Changes occurred to provide for respiration by lungs and skin.


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