Land Mammal to Whale transition: fossils Part II

In Part I of this discussion I told randman I would look for better fossilization rate/expectation data: unsurprisingly, I found so much that this Part II thread will probably evolve and die away before I can assimilate it all.But in the meantime, I wanted to share several useful data links. All of these relate to what we might expect to find and what we have found. Each of them has the potential to inform our discussion here. I plan to explore this material in detail, but it will not occur in quick forum time.The first two relate to studies of recent remains in an attempt to better understand fossilization: one primarily on land, one on the beach:I.

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Scientists have begun to study the fossilization process to understand how likely various species were to be preserved.

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That information could revise some estimates of the relative abundance and dominance of various animal species in the fossil record.

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In one long-term investigation, researchers have been studying the bones littering the landscape in Kenya's Amboseli National Park, a 392-square-kilometer reserve just northwest of Mount Kilimanjaro. During the dry season, wildlife flocks to the park's spring-fed marshes. Amboseli also contains woodlands, grasslands, and a low area that becomes a lake during rainy spells, says Anna K. Behrensmeyer of the Smithsonian Institution in Washington, D.C. She and her colleagues have systematically scoured certain paths across the plain and through the woodlands of the park since the 1970s, recording the bones they find. Most they leave in place and revisit during later surveys, but some they take back to the lab for identification and analysis.

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The article is from Science News Online, but there are linked journal citations.http://www.sciencenews.org/articles/20030719/bob10.aspII.
The second specifically addresses marine mammals in the Northern Gulf of Mexico. The link is to a complete journal article (pdf):

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Bones on the Beach: Marine Mammal Taphonomy of the Colorado Delta, Mexico

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How well does a death assemblage of marine mammal bones reflect the diversity, species composition, and proportion of bone types in the living fauna?

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http://www.geo.arizona.edu/ceam/BonesOnTheBeach.pdfIII.
Last but far from least (in fact, it is awesome, and my new favorite toy...). Check out the animated growth of the database (lower right on the linked main page):

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The Paleobiology Database is a public resource for the scientific community. It has been organized and operated by a multi-disciplinary, multi-institutional, international group of paleobiological researchers. Its purpose is to provide global, collection-based occurrence and taxonomic data for marine and terrestrial animals and plants of any geological age, as well as web-based software for statistical analysis of the data. The project's wider, long-term goal is to encourage collaborative efforts to answer large-scale paleobiological questions by developing a useful database infrastructure and bringing together large data sets.

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This hour's Database totals
14080 published references
52353 fossil collections
514558 taxonomic occurrences
entered by 157 researchers from
77 institutions in 14 countries

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John Alroy, a palaeontologist at the University of California, Santa Barbara (UCSB)...is one of the founders of the Paleobiology Database, a project set up in 2000 with financial support from the US National Science Foundation. This freely accessible database [is] hosted by UCSB's National Center for Ecological Analysis and Synthesis.

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http://paleodb.org/cgi-bin/bridge.plAgain, I apologize for not connecting more dots before posting these, but they may help ground the discussion.

MangyTiger, I agree.However, the questions I want to address are somewhat different.I believe that creationists choose cetacean evolution to scrutinize because of the perceived counterintuitive nature of evolution from four-legged land animal to fully aquatic mammal. Thus, the supposed gaps between cetacean fossils loom relatively larger in their eyes. Simply put, it is to creationists an especially large incredulity...leviathan, really However, given the ways in which the marine environment is hostile to the preservation of mammal remains, I would assert that a comparison of ancestral whale fossil finds to large land mammal ancestral finds shows that the evolutionary lineage of cetaceans is well represented. My first two links (esp. since the second directly references the first) go some distance toward defining the likely difference in preservation. Also, both studies underscore the genuine rarity of fossilization, and the absurdity of insisting that every genera and species should be present in the fossil record.I also want to demonstrate that, far from dodging questions about the fossil record, scientists have been working for decades to define taphonomic processes and expectations: far from needing to run and hide from the question, scientists have addressed it with rigorous research for many decades.Of course, the question of "How many samples along the whale evolutionary path should we expect to find?" only makes sense with the assumption of evolution (file under delicious irony), and only when gauged relative to the number of "samples" we have found in other evolutionary paths--the absolute numbers of either may be meaningless, but the relative comparison may not.I am looking not at how many whale samples we should expect to find, which is unanswerable, but rather, have we found a reasonable number?So...off-topic? A fool's errand? It promises to be a lot of work, and if I am only going to entertain randman, I'd rather drink beer.This message has been edited by Omnivorous, 08-08-2005 11:47 PM

mick writes:

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See here for one example of how it has been modelled

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Thanks, mick--that's fantastic.Now I can go about my autodidactic digging without having to worry about reinventing the wheel (though I'm just the obsessive for the job) As Roseanne Rosanna Dana would say...Never mind.

MangyTiger:

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It all sounds like good stuff to me.

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I think the fool's errand part may be if you have any vague hope of convincing folks like randman.

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Naw, not since randman insisted that one generation of physicists "accepting" steady state and another "accepting" the Big Bang was evidence of hypocrisy and intellectual dishonesty among scientists...I guess as a scientist you are either guilty of intelletual dishonesty or dogmatic inflexibility: you takes your degree and you takes your chances.I try to debate in good faith, but I must confess sometimes the sputter-stutter replies give me more satifaction than a better man would take.Learning a great deal more about evolution (and ID and creationist rhetoric) is valuable, but randman's limp replies to my exposure of his collector's curve and Evopeach's rants when I hoisted him with his own "regressive falsification" petard...priceless.Here my shameful off-topic sniggering ends.This message has been edited by Omnivorous, 08-09-2005 09:12 PM

wi:

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His assertion of 90% completeness seems somehow to be based on the concept of a generalised collector's curve and a statement that all extant cetacean families are present in the fossil record.

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Let me add that I am still looking for confirmation of "all extant cetacean families are present in the fossil record" statement. I have not been able to locate that assertion elsewhere; while it is not esp. germane to the debate, I am curious about the source.

randman:

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Also, both studies underscore the genuine rarity of fossilization, and the absurdity of insisting that every genera and species should be present in the fossil record.

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Define rarity. I used this example before, but it is rare for an individual to win the lottery.

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Is fossilization that rare for a species or family of species?

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If someone won the lottery thousands of times, would it still be rare?

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How about if a whole lot of people won it thousands of times?

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I challenge you to back up your claim, in terms of whale fossils. If some species of whales or families of species of whales have numerous fossils that have been found, then "rare" is a very relative term, and we could just as easily say fossilization is "common."

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Make you a deal, randman.You support your claims: 1) that every extant species of whale is well-documented in the fossil record, and 2) that 90% of all fossil species that exist have been found, and I will support my assertions.And that doesn't mean eye-rolling smilies as you cite a flattening conceptual curve that is devoid of data points.You support your claims, I'll support mine. If you don't support your claims, why should I?

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Unless randman simply cannot believe that whales evolved from ancient land mammals. Then he doesn't have to show anything, and I, for one, am happy to allow him his disbelief. I cannot honestly think of any argument that would convince him otherwise, nor do I think anyone should care enough to try.

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Ditto. Randman makes unsupported assertions, then when pressed cites numbers and sources. Those numbers turn out to be misapprehensions or whole cloth; the sources do not bear the weight of the citation. Further elucidation of how he arrived at his numbers is demanded, and randman ignores the demand. He ignores it again. And again. Then, after the discussion continues for a while, he begins to assert that he, at least, has provided some data, unlike the obstructionist evos. If "evos" cannot irrefutably disprove his unsupported negative assertions, he declares victory.Randman is playing rope-a-dope.This message has been edited by Omnivorous, 08-15-2005 04:53 PM