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Politics : The Environmentalist Thread -- Ignore unavailable to you. Want to Upgrade?

To: DavesM who wrote (20992)	3/26/2008 10:49:38 AM
From: neolib	Read Replies (1) \| Respond to of 36917

It has been extremely difficult to pin down specific cause and effect in ANY evolutionary development. In fact, this is something that causes Creationists much glee. About the best we can do is look at specific environmental conditions, and try to find single mutations that result in selection. Some examples are Darwin's Finches, antibiotic resistance in bacteria, chemical resistance in insects, and those famous Moths in England. Now, despite being able to directly observe the pressure, sample the population, and do DNA analyses for mutations, it has proven difficult to attribute clear evolutionary changes. Resistance to toxins are the most clear examples, and most people accept such evidence. AFAIK, there is absolutely zero agreement on any environmental factors or cultural factors, leading to anything remotely as complex as actual speciation. We have not even a clue yet as to what genetic differences are the fundamental ones between us and chimps, let alone a prayer of a hope of showing why, when, or how they originated. If you think that support for something like AGW is shaky, the support for a claim as to what drove human speciation is nonexistent by comparison. At best, one can make some handwaving arguments and link them to data which shows temporal correlation. That is far from looking convincing.

To: DavesM who wrote (20992)	3/26/2008 8:40:25 PM
From: neolib	Read Replies (2) \| Respond to of 36917

The abstract of his paper: Cooking is a human universal that must have had widespread effects on the nutrition, ecology, and social relationships of the species that invented it. The location and timing of its origins are unknown, but it should have left strong signals in the fossil record. We suggest that such signals are detectable at ca. 1.9 million years ago in the reduced digestive effort (e.g., smaller teeth) and increased supply of food energy (e.g., larger female body mass) of early Homo erectus. The adoption of cooking required delay of the consumption of food while it was accumulated and/or brought to a processing area, and accumulations of food were valuable and stealable. Dominant (e.g., larger) individuals (typically male) were therefore able to scrounge from subordinate (e.g., smaller) individuals (typically female) instead of relying on their own foraging efforts. Because female fitness is limited by access to resources (particularly energetic resources), this dynamic would have favored females able to minimize losses to theft. To do so, we suggest, females formed protective relationships with male co-defenders. Males would have varied in their ability or willingness to engage effectively in this relationship, so females would have competed for the best food guards, partly by extending their period of sexual attractiveness. This would have increased the numbers of matings per pregnancy, reducing the intensity of male intrasexual competition. Consequently, there was reduced selection for males to be relatively large. This scenario is supported by the fossil record, which indicates that the relative body size of males fell only once in hominid evolution, around the time when H. erectus evolved. Therefore we suggest that cooking was responsible for the evolution of the unusual human social system in which pair bonds are embedded within multifemale, multimale communities and supported by strong mutual and frequently conflicting sexual interest. What an incredible string of speculation hung on one very shaky piece of data, which is likely very questionable. AFAIK, nobody is claiming that any specific fossil species from 1.9 mya is likely to be in our linage. Yet this guy speculates on a cascaded sequence of behavioral changes that he thinks drove reduced dimorphism in our actual ancestors and attributes it all to cooking? This guy is amazing! Does his paper also speculate on a similar cascade of detailed behavioral changes which cropped up as the result of developing tools, and does he look at the time line of tools in the fossil record and tease apart any conflict in his complex speculations which might be attributed to tools vs. cooking. Unfortunately, papers such as his are the best fodder for creationists. They are the so called "just so" stories, which are flights of fancy not tethered by the weight of much data. Consequently they can soar as high and far as their author and audience can imagine. Creationists have made some actual useful contributions by wacking some of these. When scientists switched to a long age of the earth mode of thinking, they created "just so" stories of much of the data they looked at, with a near universal avoidance of anything sounding catastrophic, especially if it were a flood (for obvious biblical reasons!). Of course, much of what we see geologically is in fact catastrophic. It is very interesting to read the geologic history of the area I live in, with the Missoula Floods. The guy who figured this out, one J Harlen Bretz, had an uphill fight with the scientific community, because they were not in the mood to hear geological explanations based on big floods. They had banished that beast and didn't want it back. Oops! (BTW, Bretz was NOT a creationist, and of course, the Missoula Floods were not global, so the creationists were not "right" either) It is also useful to note, just as with CO2/Temp phase, that Bretz saw the smoking gun of a very large flood in one very obvious piece of data which had a clear explanation: He saw very large ripple marks in the channelled scabland of easter Washington which implied a deep and fast water flow. Nothing else covered the data. Of course, once he was off and running, much other data fell into place as well with that explanation. Same thing in AGW. It is possible that fire use is similar in human evolution to Bretz's ripple marks, but in this case there is plenty of conflicting data which needs to be explained as well. An the cascade of speculation above is rather more twisted than staring at ripple marks and saying, gee, what could make these. If interested, here is the link: en.wikipedia.org