There is a really interesting paper, just available online, that speaks directly to this question. The paper is about something else but the model parameters can be translated into expected life-spans of homonin taxa.
Bokma, F., V. van der Brink, and T. Stadler. In press. Unexpectedly many extinct hominins. Systematic Biology. (available online as an "early view" paper). http://onlinelibrary.wiley.com/doi/10.1111/j.1558-5646.2012.01660.x/abstract -lh On Jul 19, 2012, at 9:45 AM, Neahga Leonard wrote: > Hi William, > > As far as I understand it, most of the studies on past organisms are done > at the genus level, not the species level, making accurate evaluations of > species-life-spans exceedingly difficult. The fuzziness of where the line > is drawn dividing where one species becomes another adds yet another level > of difficulty. > > The fossil record bias toward preserving remains of larger animals rather > than smaller ones would also seem to impart a potentially heavy bias in > estimating species-life-spans as well. > > Within the homo/Australopithecus lineage, *H. erectus*, has had the longest > run so far, with most of the other branches of the family being relatively > short-lived. I don't know of any agreement as to why this is. I've heard > suggested that it's a product of poor fossil record, that it is a > reflection of a period of rapid evolution with many different forms > speciating rapidly, then dying off, and that it is an artifact of > artificially creating different species categories. > > The article below indicates a mammal average species-lifespan within the > time-frame you've mentioned, but that estimate may be subject to some of > the biases I mentioned earlier. > > "Mammals are among the fastest-radiating groups, being characterized by a > mean species lifespan of the order of 2.5 million years (Myr)1, > <http://www.nature.com/nature/journal/v443/n7112/full/nature05163.html#B1>2<http://www.nature.com/nature/journal/v443/n7112/full/nature05163.html#B2>. > The basis for this characteristic timescale of origination, extinction and > turnover is not well understood." > > http://www.nature.com/nature/journal/v443/n7112/abs/nature05163.html > > Good luck with your search, I'd be very curious to learn what you discover. > > Neahga Leonard > > On Thu, Jul 19, 2012 at 10:37 AM, William Grove-Fanning < > [email protected]> wrote: > >> To clarify: I >> mean the the lifespan of the sub-species Homo sapiens sapiens, not the >> life-span of its >> individual members. I believe that for species of larger mammals, it is >> around 1-2 >> million years, but need to firm up and be able to cite any such number. >> >> Thanks Again, William >> >>> Date: Wed, 18 Jul 2012 10:16:39 -0500 >>> From: [email protected] >>> Subject: [ECOLOG-L] Lifespan of the Modern Human (Homo Sapiens Sapiens) >>> To: [email protected] >>> >>> I am doing research for a paper that requires a fairly general answer >> to what appears to be, at least on the face of it, a fairly simple >> question. But I am having a heck of a time finding any sort of answer. >> Here is the question: >>> >>> Has anyone estimated or tried to estimate the life span of the modern >> human (homo sapiens sapiens)? >>> >>> The question, of course, gets muddied quickly with the possibility of >> genetic manipulation and other self-directed evolutionary interventions; the >>> creation of isolated human populations in space; and a global disaster >> that wipes out all life on earth. But assuming a “base rate” of human (or >> mammalian or large mammalian) speciation, how long is the modern human, as >> a sub-species, expected to be around? Alternatively, what is the average >> life span of members of the genus Homo (e.g., Homo sapiens, Neanderthals, >> Homo erectus, etc.)? >>> >>> >>> >>> If someone could point me to a citable source, I would reallyappreciate >> it. Thanks! William >>> >>> - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - >> - - - - - >>> William Grove-Fanning, Andrew W. Mellon Fellow >>> Department of Philosophy, Environmental Studies Program, Trinity >> University >>> Secretary-elect, Newsletter Editor, & Website Manager, International >> Society for Environmental Ethics >>> >>> >> Luke Harmon Assistant Professor Biological Sciences University of Idaho 208-885-0346 [email protected]
