Question

List the four orders of mammals that have transitioned from land back to the marine environment.

Answer 1

Marine mammals are classified into four different taxonomic groups:

Cetaceans whixh includes whales,dolphins and porpoises.

Pinnipeds includes seals,sealions,and walruses.

Sirenians which includes manatees and dugongs.

Marine fissipeds includes polar bears ans sea otters.

Each taxonomic marine mammal group evolved from a different group of land mammals,whose ancestors seperately ventured back into the ocean environment.Apart from these different origins,many marine mammals evolved similar features ,streamlined bodies,paddle like limbs and tails through convergent evolution.They are found in marine ecosystems around the globe.They are a diverse group of mammals with unique physical adaptations that allow them to thrive in the marine environment with extreme temperatures,depths,pressure and darkness.They meet the charcteristics of all mammals,ie they breathe air through lungs,are warm blooded,have hair and produces milk to nurse their youngones etc....