Anthropogenic Mass Extinction. Homo sapiens and the Evolution of the Biosphere since the Pleistocene. Kyle Burchett University of Kentucky. Mass Extinctions of the Past. → Unavoidable Prolonged Geologic Events. Cosmic Collisions. Mass extinctions are normal events for Earth’s life forms.
Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.
Anthropogenic Mass Extinction
Homosapiens and the Evolution of the Biosphere since the Pleistocene
University of Kentucky
Prolonged Geologic Events
Mass extinctions are normal events for Earth’s life forms.
“In a sense we are like fruit flies, which live but a few weeks and cannot experience most seasonal changes, much less a year. We cannot know from experience the history of planet Earth. Most of it is destined to be as abstract to a layperson as the dimensions of the universe” (Martin 2005:54).
The Pleistocene Puzzle
(Generally construed as non-anthropogenic)
Anthropogenic or otherwise
(Nogués-Bravo et al. 2010:2444)
Extreme climate changes radically alter the possible biotic composition of ecosystems.
(Delcourt and Delcourt 2004)
Extinction may be the only possible response for some species.
Competition for limited available resources increases drastically both within and across species.
If access points to alternate habitats are cut off, migration is not an option.
(Grayson and Meltzer 2002)
(Boyer 2008; Martin 2005)
Extinctions prior to invasion of Homosapiens
Long duration of coexistence
Europe and Northern Asia
(Hofreiter and Stewart 2009:R589)
(Rothschild and Laub 2006)
(Rothschild and Laub 2006:562)
European introduction of diseases such as measles and smallpox reduced Native American populations by perhaps as much as 95 percent (Dobyns 1993).
(Lyons et al. 2004b)
Climate Change + Infection + Keystone Invasive Species = Mass Extinction Event
with Homosapiens tipping the scale. . .
. . . an invasive species
with life-negating metaphysical beliefs
about. . .
fundamentally separable from all other life forms that have ever existed on the Earth
with little regard for the consequences
Man has been educated by his errors: first, he saw himself only incompletely; secondly, he endowed himself with fictitious attributes; thirdly, he placed himself in a false rank order in relation to animals and nature; fourthly, he invented ever new tables of goods and for a time took them to be eternal and unconditioned . . . .
Nietzsche, GS 115 (1882)
One species every 20 minutes.
This rate is more than one thousandfold greater than the natural background rate (Pimm et al. 1995, Wilson 1992).
Even though human-induced species extinction presently seems to rank low on people’s attention scale compared to other political and societal topics, this does not mean that its significance in earth history or its ecological consequences have diminished in any way. It must repeatedly be made clear that if current trends continue, within the next one hundred years half of all our planet’s species will most likely have become extinct. Thus, members of today’s generation are witnesses and also perpetrators of the greatest catastrophe in the history of life since the disappearance of the dinosaurs 65 million years ago.
- Martin Gorke, 2003
due to Homosapiens’ expanding invasion of ‘novel’ ecosystems
Amazon deforestation in the state of Rondônia in western Brazil, 07.30.2000
Amazon deforestation in the state of Rondônia in western Brazil, 08.21.2009
The fragmentation of natural habitats essentially creates isolated ‘islands’ where species’ vulnerability to extinction is heightened as the ecosystem processes and services they depend on for survival are disrupted by biodiversity reduction, competition with invasive species over a shrinking resource base, pathogen dispersal, pollution, and numerous other anthropogenic factors.
If India alone adopted the consumption pattern typical in the US, the global ecological impact would be as if the world’s population had doubled to 13.2 billion (Cox 2008:114).
Hubris today characterizes our whole attitude towards nature, our rape of nature with the help of machines and the completely unscrupulous inventiveness of technicians and engineers.
- Friedrich Nietzsche, GM (1887)
. . . but not always on an anthropocentric timescale.
It usually takes 10 million years for Earth’s multicellular biodiversity to ‘return’ to pre-mass-extinction levels. It took 100 million years after the end-Permian event (Benton 2003:155).
The duration of Homo sapiens’ tenure depends on future consumption practices.
Homosapiens is part of the natural world and is just as susceptible to extinction as Earth’s other organic beings.
Earth is becoming less biodiverse as a result of the escalating global invasion and consumption practices of Homosapiens.
What kind of biosphere are we creating? Will it support the continued existence of organisms such as ourselves?
There is only one Earth.
Blessed are the meek. . .?
It’s a small world, after all. . . .