Bird resurrected from extinction (iterative evolution) + What do marine mammals drink

#1
Meet the bird that refuses to die
https://www.forbes.com/sites/grrlscienti...es-to-die/

INTRO: Fossils reveal that an extinct species of flightless bird returned from the dead by recolonizing its former island home and evolving back into existence twice in less than 20,000 years through an unusual process known as ‘iterative evolution’.

Fossils reveal that an extinct species of flightless bird returned from the dead by re-colonizing its former island home and evolving back into existence twice in less than 20,000 years. The white-throated rail from Madagascar in the south-western Indian Ocean colonized the tiny Aldabra Atoll in the Indian Ocean and became flightless before the island and everything on it was swallowed by rising seas 136,000 years ago.

“Aldabra went under the sea and everything was gone,” Natural History Museum avian paleontologist and lead author of the study, Julian Hume, explained in email. “There was an almost complete turn over in the fauna. Everything including an endemic crocodile and a duck, as well as the tortoise and the rail went extinct. Yet, as the Aldabra rail still lives on today, something must have happened for it to have returned.”

The Ice Age is what happened: it caused sea levels to drop so Aldabra resurfaced some 118,000 years ago. Thus, the white-throated rail recolonised the island and once again lost its ability to fly, giving rise to the flightless bird that we know today. (MORE)



What do marine mammals drink?
https://www.treehugger.com/animals/what-...drink.html

EXCERPT: . . . Whales, dolphins, sea lions and other marine mammals ... They live in saltwater; but do they also drink it?

Marine biologist Robert Kenney of the University of Rhode Island explains that some marine mammals have been known to occasionally partake in the salty stuff, but they rely on other options. They often get the water they need from the food they eat [...]

Even so, marine mammals get a lot of salt ... and they have ways to get rid of it. Seawater is three times saltier than blood (of both terrestrial and marine invertebrates). So sea animals get rid of extra salt by producing super salty urine. [...] Some seals will eat snow to get their fresh water; meanwhile, California sea lions can get enough water from the fish they eat and can live without actually drinking any fresh water at all.

And while you might think that seabirds have it easier [...] they still have some pretty nifty tricks up their wings. As The Times explains, "seabirds have special organs called salt glands above their eyes that extract excess salt from the bloodstream and excrete it through the nostrils." (MORE - details)
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#2
Trying to get this particular iterative evolution straight.....the bird that became the flightless rail was the one that recolonized the island. A repeat evolution occurred and the white throated rail reappeared. Is that it? Interesting set of genetic instructions that under the same conditions introduced a rebirth.

Made me wonder about Panspermia for a moment. Perhaps if something survives long rides in space and eventually sets up shop on many new worlds, then life in the universe is iterative. Maybe not exactly as in species but in life forms (ie...head, eyes, limbs).
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#3
(May 29, 2019 12:08 PM)Zinjanthropos Wrote: . . . Made me wonder about Panspermia for a moment. Perhaps if something survives long rides in space and eventually sets up shop on many new worlds, then life in the universe is iterative. Maybe not exactly as in species but in life forms (ie...head, eyes, limbs).


That would be nice. Vaguely seems like there was even an old STNG episode that tried to explain why humanoids were ubiquitous in the galaxy of Star Trek. Due to a vastly ancient and vanished civilization that had seeded the Milky Way billions of years ago and deliberately designed those panspermic "carriers" to loosely follow certain evolutionary avenues when arriving on suitable worlds.

But in an arbitrary context where is no "invisible hand" like that... Single-celled microorganisms would be the most common candidates to endure in space, which means they would not have evolved the combinations of genes that carry and regulate the development of multicellular life: Differentiation into specialized cells constituting tissues and organs with unique functions, and morphology (body form). The group of related genes called "Hox", for instance, dictate the body plan of an embryo.

OTOH, monocellular eurkaryotes do carry the homeobox genes that Hox evolved as a subset of during the arrival of Metazoa and bilateria (iteration possible?). And the tardigrade is even a polycellular critter that could survive in space. But tardigrades lack many gene components of the Hox group.

The farther one goes back in terms of primitive organisms on Earth, the less likely evolution would follow the same pathways it has in our past. Alternatives to what makes known complex life possible would have more opportunity to emerge, although the selective pressures of parallel evolution could come into play to outwardly generate some familiar adaptations. But the factors of parallel evolution don't equate to literal iteration of a species at both the genetic and specific body-features level (only a rough resemblance with regard to the latter and functions).

Molecular blueprint alternatives to how complex life on Earth is governed would evolve in other planet situations that received single-celled space migrants unrelated to ours.
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