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| A world without Crocodilia | |
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| Topic Started: Jul 31 2017, 11:51 AM (1,294 Views) | |
| kusanagi | Aug 1 2017, 09:47 AM Post #31 |
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Adolescent
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The word anthropocene is useful in discussions of mass extinction. Technically humans changed ecosystems probably since firestick farming became more widespread in the Holocene to manage small prey as a response to climate change although the practice has been inferred for the Pleistocene and was probably used by all H. sapiens hunter gatherers since the beginning excepting in tundras. If you want to be pedantic the Holocene is just a Pleistocene interglacial anyway, it is just one in which land management and watercraft made humans a global keystone species.
Edited by kusanagi, Aug 1 2017, 09:50 AM.
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| IIGSY | Aug 1 2017, 09:53 AM Post #32 |
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A huntsman spider that wastes time on the internet because it has nothing better to do
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How is it useful for mass extinctions? Just say that ... "There will be no more dwarf crocodilians or long-snouted gavial type crocodilians immediately after the holocene" |
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Projects Punga: A terraformed world with no vertebrates Last one crawling: The last arthropod ARTH-6810: A world without vertebrates (It's ded, but you can still read I guess) Potential ideas- Swamp world: A world covered in lakes, with the largest being caspian sized. Nematozoic: After a mass extinction of ultimate proportions, a single species of nematode is the only surviving animal. Tri-devonian: A devonian like ecosystem with holocene species on three different continents. Quotes Phylogeny of the arthropods and some related groups In honor of the greatest clade of all time More pictures Other cool things All African countries can fit into Brazil
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| kusanagi | Aug 1 2017, 10:00 AM Post #33 |
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Adolescent
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Because present extinctions are anthropogenic and for that matter throughout the Holocene man's fire management as a "herbivore" has constrained the nature of ecosystems. Evidence of firestick farming exists in Pleistocene Africa but not convincingly for neanderthals as the one possible occurrence is just a coincidence (Perhaps the number of cognitive steps necessary for managing landscapes in advance was unique to H. sapiens?), so yes the Holocene is the age of H. sapiens and of his landscape engineering eventually including swiddening and then even industrial civilisation. Edited by kusanagi, Aug 1 2017, 10:02 AM.
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| IIGSY | Aug 1 2017, 10:01 AM Post #34 |
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A huntsman spider that wastes time on the internet because it has nothing better to do
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Most major extinctions dating back to the pleistocene where anthropocentric. I don't see your point. |
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Projects Punga: A terraformed world with no vertebrates Last one crawling: The last arthropod ARTH-6810: A world without vertebrates (It's ded, but you can still read I guess) Potential ideas- Swamp world: A world covered in lakes, with the largest being caspian sized. Nematozoic: After a mass extinction of ultimate proportions, a single species of nematode is the only surviving animal. Tri-devonian: A devonian like ecosystem with holocene species on three different continents. Quotes Phylogeny of the arthropods and some related groups In honor of the greatest clade of all time More pictures Other cool things All African countries can fit into Brazil
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| kusanagi | Aug 1 2017, 10:27 AM Post #35 |
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Adolescent
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I don't believe they were as anthropogenic extinctions were rare in the Holocene till the early modern period or the disruption of island ecosystems. As I explained in other threads Western civilisation drew away from other world civilisations both in technology and in values during very recent centuries and especially during the industrial revolution, with the rise of the global capitalist world system, new resource demands such as combustibles for industry, new medicines increasing human populations and other things besides. Nowadays I am convinced the earlier Pleistocene megafaunal extinctions were primarily due to natural climate change not overhunting. Though the intensification of land management by fire which was itself a response to that climate change had introduced a new, rival "herbivore", consuming vegetation indisciminantly and efficiently, and preventing what would otherwise have been normal landscape recovery for megafauna. On continents human hunting probably didn't wipe out anything but small residual pockets of megafauna if even that, but firestick farming had turned swathes of North America and Australia into ancient, managed parkland at the time of European arrival. Firestick farming is something uniquely H. sapiens though other later hominins possessed hearths, demonstrating that they fed and managed fires like modern hunter gatherers such as the Tasmanians, but periods of absence of fire at continuously inhabited sites suggests they lacked a means of ignition. Whereas all living human cultures inherited the friction method despite claims to the contrary for Tasmanians, Andamanese etc. There is no human culture without ignition technology: it is the modern human cultural package. Firestick farming is unknown in non-sapiens sites at set the stage for farming such as swiddening, a form of firestick land engineering. Other hominins did not become farmers but Homo sapiens did, several times around the world by innovation and imitation, having been pre-adapted to plan the productivity of the land. A regular dependence upon large game hunting is not a cultural universal. In the modern day hunter gatherers and peoples combining elements of food production with resource extraction are mostly not as reliant upon eating large animals for protein as people assume they are, and the meat consumed was mainly small game and fish. The Pleistocene extinction patterns do not match the usual correlation that exists between reliance upon animal protein and latitude, as you would expect were human hunters involved. An important part of the Upper Paleolithic in Europe was in fact the first appearence of fishing equipment and modern humans arrived more efficient at catching small game such as rabbits than were neanderthals, giving modern man reliable access to more fallback foods and enabling new fishing economies in Europe. The Holocene/ethnohistorical Tasmanians with an Upper Paleolithic toolkit obtained meat near-entirely from wallabies - yes further south in Australia the abos ate more meat and fish, and only further south did they build the permanent fish traps known to archaeologists. To this day or at least until very recently the most predatory of native Siberians and the Ainu of nearby Hokkaido, though they had acquired domesticated reindeer and sometimes other forms of food production as late adopters, are or were still extensively reliant upon salmon runs whereas the tropical African, Indian and Southeast Asian hunter gatherers and northern Australian natives were all consuming much less animal protein, relying far more on foraging with their hands in place of hunting with stone or other tools such as boluses or boomerangs. The idea that "primitive" peoples were globally great hunters of big game species lies at the root of the overkill hypothesis, and yet it is a projection onto "noble savages" based upon the prestige of the hunt in early modern Europe, filtered through Victorian notions of nature as red in tooth and claw. In the well studied Kalahari, hunter gatherers are far less efficient at hunting large mammals than outside people believe thanks to documentaries featuring staged hunts of game as large as giraffes, and their diet is nowhere near as carnivorous as the public now believe, either. When a large animal crosses vegetation the hunters simply break the trail - this is the reason most large predatory mammals depend on senses other than sight, perhaps? https://www.jstor.org/stable/2741506 As regards crocodilians the only possibly anthropogenic extinctions are mekosuchians in the southwestern Pacific and Voay on Madagascar. Aldabrachampsa was present on Holocene Aldabra but was extinct by the arrival of Europeans. The timing of the extinction of Voay is unknown but the Pacific mekosuchians Mekosuchus and Volia would presumably (but not 100% definitely) have encountered man. The Madagascan extinctions were probably caused primarily by land management for farming and Malagasies retain a poor knowledge of most former megafauna, for example there is little or no folk memory of Aepyornis there, suggesting the giant flightless ratites were not economically important - unlike the moas at the other end of the Austronesian expansion, in New Zealand. On Madagascar the killing of large C. niloticus took place only to a small extent before the arrival of Europeans in the 16th century and big crocodiles were still found in Madagascar in high densities until the last century. Voay was unlikely then to have been hunted extensively by the iron age Malagasy farmers. Crocodylus replaces Voay late in the Holocene with no discernible period of coexistence, suggesting C. benefitted from human arrival on Madagascar freeing an ecological niche in the interior. Crocodylus possess well developed salt glands suggesting the genus is primitively brackish to marine, so did C. niloticus inhabit the saltwater habitats whilst Voay (like Osteolamus and Mecistops) lived in inland freshwaters and initially outcompeted their neighbours? The so-called Murua gharial of the Plestocene Solomon Islands may have disappeared before human arrival as might the huge mekosuchian Quinkana of the Australian mainland leaving only Voay, Volia and Mekosuchus as the only crocodilians reasonably inferred extinct because of overkill or other human activities as far as is known. Overexploitation but not yet any global extinction of crocodilians is otherwise limited to very recent centuries and more recent demands such as the crocodile skin market. Edited by kusanagi, Aug 1 2017, 03:46 PM.
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| ÐK | Aug 1 2017, 10:58 AM Post #36 |
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Adult
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For the record guys, to avoid long quote-chains like this you can cut them down to only the previous message in the quoting box when you're posting. Or better yet in situations like this, you don't even need to quote the last person since it's pretty clear who and what you're addressing. Helps make the place look just a bit neater, y'know? |
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~Projects~ • Earth Without Earth; Like nothing on Earth...
~Mark Witton, Pterosaurs (Chapter 3, page 18)
~Troll Man, Skype (15/2/15)
~Komodo, Zebra's sent back in time (4/1/13) | |
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| TAXESbutNano | Aug 2 2017, 05:15 AM Post #37 |
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I'm going back to basics.
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I believe the current accepted hypothesis is not hunting of humans' prey animals, but hunting of their predators- a glance at Wikipedia shows that die-offs correlate pretty well with a crisis from climate change and overpopulation of herbivores creating a 'whiplash' that killed off big herbivores. |
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| kusanagi | Aug 2 2017, 07:13 AM Post #38 |
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Adolescent
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Paleolithic man might steal niches from other predators but not wipe them out directly and so in the process would become a regulator of herd numbers himself. Otherwise there would be no need to eradicate cave lions or smilodons or the like. An interesting case is teratorns because their prey size would be that preferred by Californian "digger" Indians today. Niche competition was a role when man arrived especially for other hominids like neanderthal man and perhaps the cave bear which disappeared at the same time, but like hunting pressures it would not have been constant. Africa had few extinctions, extending into the mid Holocene, and involved mostly forgot fermenting herbivores. Eurasia had very few and in two pulses, one at the end of the Mousterian and another in the early Holocene persisting in pockets well into the historical period. Australian megafaunal extinctions were early and this may support overkill, but there is a lack of archaeological evidence and Pleistocene Australians lacked the woomera or spear thrower. It is unclear how many megafauna coexisted with man in Sahul and in Tasmania where the latitude encouraged human carnivory the preference for wallaby was present ready in the Pleistocene. In the New World the arrival of "paleoindian" big game hunters or thereabouts does at least correlate with ecological collapse. That of the "paleoamericans" of Minas Gerais, not so much. In both NW continents the extinctions were mostly hindgut fermenters else ground sloths which are functionally closer to elephants than ruminants. In South America genera like Catonyx and Notiomastodon existed into the Holocene alongside hunter gatherers of Botocudo type who hunted only small game unlike the Clovis people: thus as in Eurasia where megafaunal extinction was less of a thing, extinction was protracted. |
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| TAXESbutNano | Aug 2 2017, 07:57 AM Post #39 |
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I'm going back to basics.
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In regards to the fewer Eurasian-African extinctions, those animals coexisted with humans (or at least the genus Homo) for longer than American and Australian ones, making them more wary and less vulnerable- there's a general correlation between maximum predator size and how long humans have been in that habitat. (I believe forest habitats might be somewhat of an exception judging from bears and maybe tigers but eh.) Persecution of carnivores isn't done for dietary needs- more percieved self-defense, reduction of competition and later defense of livestock. This means the killed predators are disproportionate to human presence, so humans populations remain stable but carnivores drop, ultimately resulting in too few large predators to hunt the remaining prey (especially considering that less than a third of the current healthy human diet is composed of meat). |
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| kusanagi | Aug 2 2017, 08:27 AM Post #40 |
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Adolescent
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Reduction of competition is something I addressed and defence of livestock came later in the Holocene; contrary to popular expectation historical societies plaed little concern upon pre-emptive self-defence from other predators. Extermination of wolves for instance was rooted almost entirely in economic factors with very little worry for very few human fatalities. Too little is yet known of the Australian situation but in the mid Holocene a cultural revolution saw a shift to smaller prey in central Australia. To be honest this might correspond with the arrival of Pama-Nyungan speakers, rather than a cultural shift and it was not caused by an extinction of large prey (besides, the megafauna was then gone for millenia). Thereby strengthening the argument that different cultural groups have different ecological impacts, and without the woomera the Pleistocene Australians would have less impact still on large mammals. Mid Holocene niche stealing by Pama-Nyungan(?) people and dingos impacted mainland thylacines and Tasmanian devils, and at this time the native hen was impacted on the mainland. Much earlier the diprotodontids and large wombats were hindgut fermenters of browsing habits and therefore vulnerable to climate change and the sthenurines should be interprted so as they diverged before the evolution of foregut fermentation in macropodoids. Similarly the dromornithids and meiolanids were also hindgut fermenters. In North America no one could doubt the efficiency of Clovis people or their use of the atlatl; counterarguments always depend upon other grounds, such as prey selection at archaeological sites and the relationships of certain extinct megafauna such as mamoths to species that survived elsewhere. At come sites such as La Brea the climate might not have shifted that much but at others it clearly did and habitats sch as Nearctic savannahs declined. South American indigenous people of Minas Gerais do not derive from a Clovis source and hunted small game, as their Gean speaking descendants did when Europeans dispossessed them. If this can be used to explain a local survival of megafauna well into the Holocene as a counterpoint to the impact of Clovis-derived cultures down to Patagonia, it cannot explain their final, global extinction as anthropogenic. Fortunately the Clovis type people survived relatively unmodified to be encountered by visitors such as Darwin, although they had a Mesolithic grade of culture then: they represent the Patagonian culture area, which was almost unique in ethnohistorical times for its combination of nomadism, hypercarnivorous subsistence and kinship structure (though intriguingly Asian fishermen called Selung have a similar cultural profile at sea). Their limb proportions and pelvvises show the same combination of cold adaptaion and "tropical" (long limbed) limb proportions that are seen in the Paleoindians and for that matter, Ice Age European hunters and even some late neanderthals. Besides the fact they were the most conservative descendans of the Paleoindian people, as shown by their cranial mophology and overall robustness, their anatomy and culture reflect cold climate, Pleistocene hunters more generally. An important thing that stands out about the American Cone hunters is that the Fuegians and Patagonians subsisted upon species related to North American Pleistocene camelids that went extinct: why if this was a Clovis overkill? Edited by kusanagi, Aug 2 2017, 09:19 AM.
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| TAXESbutNano | Aug 2 2017, 09:16 AM Post #41 |
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I'm going back to basics.
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I counter-argumented the reduction of commpetition though. Thou must provide a counter-counterargument upon that counterargument, good madam! In modern times, even wary predators can be major predators of people- in these past two centuries alone tigers have taken well over 300,000 people, nearing 400,000- and tigers genrally refuse to enter human habitation. For stone-age hunter-gatherers, without permanent habitation and facing predators that had never learned to fear humans, it's likely a much higher proportion of them (i.e a personally-notable number) met predation-related deaths. This, combined with other factors such as economic hunting, cultural rituals and removing competitors from kills or the local area, is plenty of reason for a group of humans to hunt predators- and cultural grudges are enough to finish the job. |
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| kusanagi | Aug 2 2017, 09:23 AM Post #42 |
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Adolescent
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I don't know, plenty of hunter gatherer groups survived into the ethnohistorical period but what was their impact on potential predators? Bushmen for example live alongside several dangerous species of predatory mammal. Does anyone know their ecological impact upon large felids and the like? |
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| TAXESbutNano | Aug 2 2017, 09:36 AM Post #43 |
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I'm going back to basics.
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The main difficulty with the comparison is that there aren't any unwary predators of humans around- big cats and whatnot generally refuse to hunt humans unless desperate or not taught to avoid them. In addition, simulations seem to correlate with what the fossil recprd shows (see Second-Order Predation, which provides a reason for predators hunting humans- the reduction in prey numbers via climate change and anthropogenic hunting). ...I just remembered, this discussion was started via a semantic debate on holocene vs anthropocene. I say it doesn't really matter between the two words. However, this debate is fun so feel free to continue. |
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| kusanagi | Aug 2 2017, 09:53 AM Post #44 |
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Adolescent
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Well without inferences from Pleistocene appropriate peoples, there can be no modelling of Pleistocene ecological impacys oc large carnivores or anything else. Wikipedia does accurately refute the second order hypothesis at the link so I will just repeat choice bits.
Though for what it is worth the large European carniores died out in refugia as large as Iberia and would be more vulnerable than mammoths or Irish elk to being "pocketed" into refugia should the climate change. |
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| TAXESbutNano | Aug 2 2017, 10:03 AM Post #45 |
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I'm going back to basics.
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Hmm. I guess it is a mystery as to exactly what happened, then- which thinking on it is the current scientific consensus. ...Yay? |
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Technically humans changed ecosystems probably since firestick farming became more widespread in the Holocene to manage small prey as a response to climate change although the practice has been inferred for the Pleistocene and was probably used by all H. sapiens hunter gatherers since the beginning excepting in tundras. If you want to be pedantic the Holocene is just a Pleistocene interglacial anyway, it is just one in which land management and watercraft made humans a global keystone species.




















7:51 PM Jul 10