Organism Physiology Paper

BIO101

April 15, 2014

Organism Physiology Paper

The Sea Lion is the Organism that I want to discuss in this paper today. It has a highly controversial on weather this animal was a land walker only and when it actually acclimated to water, and why. After spending numerous hours researching this organism, it is still unclear to me when and why this animal changed its environment to include water.

It is believed by many in the scientific world that the Sea Lion was a land dweller and became a water creature due to not have enough food in its land environment. “It's long been assumed that marine mammals in the pinniped group – seals, sea lions and walrus – evolved from a land-based common ancestor, but until now, no definitive fossil evidence had materialized” (Harmon, 2009). The animal would have had four legs that would have become webbed after its transfer to water. Its adaptation would have allowed it to survive under water for longer periods as well. The creature would have more than likely looked like the picture below if this is an accurate depiction of its ancestry.

[pic]

Its evolution would have included, being able to walk on land with paws that grip the earth, breathe air always to changing itself allowing it to breathe underwater and swim like a fish. Its paws slowly formed to fin like water movers however it still is able to move about on land. The creature shown above is believed to swim as shown looking for fish and other smaller life forms. It also was believed to hunt on land for smaller animals as well. It is believed that when the food ran out on land the animal slowly move its environment to the water.

The above mentioned creature’s fossilized remains were found recently and believed to connect our Sea Lions of today to the land creature you see above. Scientist are calling the creature Puijila Darwini. “Although land animals are assumed to have initially evolved from sea-dwellers, some – such as the ancestors of whales, manatees and walruses – eventually crept back into the watery habitat, which makes these transitional species like Puijila an important glimpse into that evolutionary process” (Harmon, 2009). As its environment around him changed it had to make these changes to survive itself.

“The remarkably preserved skeleton of Puijila had heavy limbs, indicative of well-developed muscles, and flattened phalanges which suggests that the feet were webbed, but not flippers. This animal was likely adept at both swimming and walking on land. For swimming it paddled with both front and hind limbs. Puijila is the evolutionary evidence we have been lacking for so long," says Mary Dawson, curator emeritus of Carnegie Museum of Natural History” (Anonymous, 2009). The above shown animal over time eventually evolved to this creature depicted below. The tail became a flipper, the webbed paws became fins and the body itself became sleeker to suit underwater life.

[pic]

Reference

Anonymous, 2014, Sea Lion Evolution, Bio-Expedition.com, Retrieved From:

http://www.sealion-world.com/sea-lion-evolution/

Anonymous, 2009, Fossil Evidence Of Missing Link In The Origin Of Seals,

Sea Lions, Walruses Found In Canadian Arctic, Science Daily, Retrieved

From: http://www.sciencedaily.com/releases/2009/04/090422132832.

htm

Harmon, K., 2009, Found: Missing link ancestor of modern sea lions, seals

and walrus, Scientific America, Retrieved From: http://www.scientific

america.com/blog/post/found-missing-link-ancestor-of-mode-

2009-04-22/?id=found-missing-link-ancestor-of-mode-2009-04-22

http://www.vallarta-adventures.com/media/images/78/original.gif