Thursday, March 15, 2007
Paleontology: Intriguing Find
Scientists at the Smithsonian Tropical Research Institute, the Scripps Institution of Oceanography, and London's Natural History Museum report that "extinctions resulting when one ocean became two [because of the land bridge known as the Isthmus of Panama] were delayed by 2 million years."
In other words, extinctions resulting from dramatic habitat change may significantly lag the causal event.
According Aaron O'Dea, a post doc, "We may be way off track when we search for the causes of extinctions by looking only at the time the extinctions occur in the fossil record..."
The scientists studied coral and snail species extinction, noting that a big "die-off" occurred about two million years after the land bridge was formed. They do not have an explanation for the delay.
I'd be curious to see if this result has implications for other extinction events. Was dinosaur extinction underway as a result of other factors (disease and vulcanism have been suggested) long before the impact of the asteroid that caused the Chicxulub crater? Apparently, dinosaur fossils become scarce before the iridium layer caused by the asteroid (and, of course, aren't found above the layer). Interesting hypothesis for research!
In other words, extinctions resulting from dramatic habitat change may significantly lag the causal event.
According Aaron O'Dea, a post doc, "We may be way off track when we search for the causes of extinctions by looking only at the time the extinctions occur in the fossil record..."
The scientists studied coral and snail species extinction, noting that a big "die-off" occurred about two million years after the land bridge was formed. They do not have an explanation for the delay.
I'd be curious to see if this result has implications for other extinction events. Was dinosaur extinction underway as a result of other factors (disease and vulcanism have been suggested) long before the impact of the asteroid that caused the Chicxulub crater? Apparently, dinosaur fossils become scarce before the iridium layer caused by the asteroid (and, of course, aren't found above the layer). Interesting hypothesis for research!
Another "God Gap" Filled
American and Chinese paleontologists discovered a new mammal, Yanoconodon, that lived in what is now China during the Mesozoic Era (125 MYA). According to the Science Daily report, the mammal "...provides first-hand evidence of early evolution of the mammalian middle ear..."
H. Richard Lane, the program director of the National Science Foundation's Division of Earth Sciences, is quoted as saying: "This early mammalian ear...reinforces the idea that development of complex body parts can be explained by evolution, using exquisitely preserved fossils."
Another strike against irreducible complexity!
And, since the "...middle ear structure...is an intermediate step between those of modern mammals and those of near relatives of mammals..." (mammaliaforms), so much for "gaps" in the evolutionary record or a lack of "transitional" forms (also, see my comments on Tiktaalik, below).
Yanoconodon and Tiktaalik. The gaps are disappearing, and irreducible complexity is just irreducibly silly. I wonder what lies the ID/creationists will tell to explain these away?
H. Richard Lane, the program director of the National Science Foundation's Division of Earth Sciences, is quoted as saying: "This early mammalian ear...reinforces the idea that development of complex body parts can be explained by evolution, using exquisitely preserved fossils."
Another strike against irreducible complexity!
And, since the "...middle ear structure...is an intermediate step between those of modern mammals and those of near relatives of mammals..." (mammaliaforms), so much for "gaps" in the evolutionary record or a lack of "transitional" forms (also, see my comments on Tiktaalik, below).
Yanoconodon and Tiktaalik. The gaps are disappearing, and irreducible complexity is just irreducibly silly. I wonder what lies the ID/creationists will tell to explain these away?
