Word: lands
(lookup in dictionary)
(lookup stats)
Dates: during 2000-2009
Sort By: most recent first
(reverse)
What really fascinates scientists about the fishapod is that it fits so neatly into one of the most exciting chapters in the history of life--when creatures that swam in seas and rivers gave rise to things that walked, ran and crept on land. The fishapod appears to be a crucial link in the long chain that over time led to amphibians, reptiles, dinosaurs, birds and mammals. Indeed, Tiktaalik roseae, the official name bestowed on the fishapod (in the language of the local Inuit, tiktaalik means "large fish in stream"), falls anatomically between the lobe-finned fish Panderichthys, found...
...eyes mounted on the top of its head like a crocodile. It also had a big, interlocking rib cage, suggesting that it had lungs and did at least part of its breathing through them, as well as a trunk strong enough to support itself in the shallows or on land. And most startling of all, when technicians dissected its pectoral fins, they found the beginnings of a tetrapod hand, complete with a primitive version of a wrist and five fingerlike bones. "This is not some archaic branch of the animal kingdom," says Shubin. "This is our branch. You're looking...
Together, these fossils have overturned the old picture of the fish-tetrapod transition, which conjured up the image of creatures like the modern lungfish crawling out of water onto land. That picture certainly didn't fit Acanthostega, whose short, flimsy legs were ill equipped for terrestrial locomotion. Rather, according to University of Cambridge paleontologist Jennifer Clack, Acanthostega was an aquatic creature that used its limbs and lungs to make a living in water. And that scenario makes sense because it sets up conditions for natural selection--the force that powers evolution--to favor transitional life-forms like the fishapod, with...
...land, observes Shubin's collaborator Ted Daeschler, chair of vertebrate zoology at Philadelphia's Academy of Natural Sciences, such an appendage would have been worse than useless. But it would have been more than adequate for propping the animal's head above the water so that it could survey its surroundings or for anchoring it underwater as it waited to ambush its prey. The advantage of being able to gulp air through lungs as well as gills would likewise have been immediate, given that the fishapod made its home in warm, shallow waters that were frequently rendered inhospitable by decaying...
...This article consists of a complex illustration. Please see hardcopy of magazine.] Source: Neil Shubin, University of Chicago 380 million years ago BEFORE TIKTAALIK Lobe-finned fish had forelimbs suitable for moving in water but not on land 375 million years ago TIKTAALIK The forelimbs had the beginnings of fingers and a wrist, wrapped inside a fin 360 million years ago AFTER TIKTAALIK Tetrapod forelimbs have wrists and digits used for crawling on land [This article consists of a complex illustration. Please see hardcopy of magazine...