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On 8/17/15 11:21 AM, Manuel Barrera via Marxism wrote:
As I commented on your blog, Louis, either produce some actual evidence with veritable 
scientific scholarship to refute the impact of early humans on fauna, flora, and 
consequent climatic change or incorporate the current evidence in a way that any Marxist 
revolutionary would do; integrating it scientifically into our theories for emancipating 
the world from the scourge of economic, social, and political devastation that is our 
current legacy in the maintenance of profit over human--and biological 
speciation's--need. Simply concluding that theories of human roles in precipating 
environmental crises--now and "then"--are invalid because some charlatans 
bastardize the science is a disservice to scientific socialism.

I supplied a link to an article in my post that I found most convincing especially when I first read it in 2003. Nothing has persuaded me since to the contrary. In fact, as was indicated in the latest computer modeling that is being reported upon now, the overhunting/extinction nexus appears to be primarily an island-based issue. I included a graph that showed the relatively low incidence within continental land masses.

Here is a relevant passage from the article I linked to:

The magnitude of prehistoric human-caused vertebrate
extinctions on islands came as a surprise when it
first began to be described in detail by such scientists as
Storrs Olson, Helen James, and David Steadman during
the 1980s [73–75,81,84]. Nonetheless, it has long been
known that island faunas are in general prone to extinction,
and the reasons for this are well understood. Island
vertebrates are vulnerable because their populations are
small, because they are confined to well-delineated areas
of land that may undergo rapid environmental change,
because they may have lost (and in some cases have
clearly lost) the behavioral mechanisms needed to cope
with introduced predators, pathogens, and competitors,
and because there is no ready source of conspecific
individuals to replenish dwindling populations [11,50,
76,79,82]. Island faunas are, as Paulay has noted,
“among the most vulnerable in the world” [76, p. 134].

Martin’s first premise is, then, depressingly true. The
initial human colonization of island after island was
followed by vertebrate extinction. That this premise is
true, however, does not mean that it is relevant to
continental extinctions. After all, the factors that make
islands prone to vertebrate extinction—small population
sizes of resident vertebrates, the lack of a ready source of
conspecific colonizers, and so on—do not apply to the
continental setting.

full: http://faculty.washington.edu/grayson/jas30req.pdf
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