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Originally Posted by mx5me
So on the topic of the age of the earth, I'll use my man Dawkin's reasoning: Creationists estimate the earth's age to be 6000 years. Scientists estimate the earth's age to be 4.6 billion years. If the scientists are correct, as several radiometric dating methods would suggest, the creationists' estimate is off by a factor of a million. This "is equivalent to believing that the distance from New York to San Francisco is 7.6 yards." (Dawkins)
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Most creationist can't even arrive at a concise age of the Earth. The common "6000 years" figure is based on the rough estimates of an Irish archbishop in the 17th century who cobbled together a timeline based on woefully incomplete geneological accounts in the Christian bible. Any real biblical support for this number is virtually nonexistent.
It's a magic number, and not all that different from the arbitrary numbers assigned to the age of creation in various other religious myths. There aren't very many serious theologians who take this figure seriously. Biblical literalism is largely an American Baptist phenomena, and is considered to be contradictory and even heretical by mainstream Christian scholars.
Given that young-earth creationists are incorrect in nearly all manners of science, history, and even theology, I'll never understand why their position is given any real consideration at all.
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Originally Posted by mx5me
On the question of the survival of flying and swimming species (and mammals): There is obviously no definitive explanation of how some creatures survived when the asteroid that is proposed to have wiped out the dinosaurs struck. One plausible explanation is that the creatures that survived were those that were able to burrow into the ground or immerse themselves in water when the environment turned extremely hot for hours after the strike.
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The mass extinction that occurred during the Cretaceous really isn't even the largest mass extinction on record. The event led to the extinction of around 70% of the organisms existing at the time. There is a great deal of evidence demonstrating that many marine and early mammalian organisms did in fact go extinct during this period. Planktonic organisms suffered especially heavy losses, as well as several species of birds, marsupials, and placentals (the common ancestor of most modern mammals.)
The K-T extinction was widespread, but rather patchy in terms of which organisms were most effected. Organisms that were largely dependent on photosynthesis were obviously effected the most by the amount of dust and debris hurled into the atmosphere by the impact event. This in turn affected the organisms whose food chain depended on other photosynthesising organisms. Omnivores and insectivores appear to have been the biggest winners in the K-T extinction being that they were able to sustain a healthy diet despite the widespread destruction. Most small mammals survived on insects, larvae, worms, snails, etc., which themselves survived largely on decaying organic matter.
The ocean-dwelling survivors also appear to have survived largely by switching to
detritus feeding. If the water column was your habitat and you relied heavily on phytoplankton, you were pretty much screwed.
Size was also a big issue. The smaller the organism, the more suited it was for survival in the harsh conditions caused by the impact event. As near as modern paleontologists and paleozoologists can tell, nothing larger than a modern house cat survived. Huge, lumbering dinosaurs that required a hefty amount of caloric intake to survive obviously wouldn't fair to well in an environment where their primary food chain was essentially blown away by a giant meteor. Some small predatory dinosaurs probably did survive the end of the Cretaceous, but it appears that their ecosystem changed so drastically that they were unable to sustain a viable breeding population.