Evolution: why some seals swim better (Evolution)

by David Turell , Friday, May 07, 2021, 01:06 (1086 days ago) @ David Turell

New hydrodynamic studies of some seals show how they handle aquatic life so well:

https://cosmosmagazine.com/nature/marine-life/how-seals-adapted-to-move-through-water/?...

"Zoologist David Hocking, formerly of Monash University and now curator of vertebrate zoology and palaeontology at the Tasmanian Museum and Art Gallery, did, and says he has now helped “to solve an evolutionary riddle at the heart of seal evolution”.

"Seals and sea lions propel themselves through the water to catch their prey – but true seals (otariids) generally use their front flippers while eared seals (phocids) use their back feet, and the other limbs are used for steering.

"Originally, the profoundly different swimming styles were thought to reflect separate ancestries, but genetic analysis shows the pinnipeds come from the same group. A new study led by Hocking and published in Current Biology now attributes it to environmental adaptation over millions of years.

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"Using computational fluid dynamics simulations, Hocking and colleagues revealed that wing-like flippers evolved in leopard seals that already swam with their back feet – presumably to give them extra speed for catching their preferred prey, notes senior author Alistair Evans.

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"...leopard seals have greatly reduced their claws and stretched out the length of the flipper to form a more effective paddle for swimming. In doing so they have independently evolved wing-like flippers similar to those of the other main family of seals, the Otariidae, which includes the fur seals and sea lions.”

"It’s one of the first studies to closely examine seal flippers as biomechanical tools adapted for swimming, according to Hocking, and helps fill in some vast gaps left by a limited fossil record.

"The findings help shine a light on how the animals evolved their body and behaviour to adapt to marine life – an incredible feat. (my bold)

“'The switch from life on land to life in water is one of the biggest transitions a species can undergo in its evolution,” says Hocking. “This has happened multiple times, with groups like whales, sea turtles, sea cows and crocodiles, all evolving from land-dwelling ancestors that have adapted themselves for a life at sea.”

“'This is fundamental knowledge that helps us to understand how the huge diversity of life we see around us first evolved on our planet.'”

Comment: Typical Darwin think. We have no idea how these adaptations happened from a natural series of chance, random mutations. Note how the authors use purpose to explain the changes. Why not consider they were designed.