What is the cause of existence?

so you claim some expertise? THEN why cant you admit that population gene frequencies decline ?

Then you are claiming that its everyone else whose picking on you? HMMM your manners are a bit wanting in polite conversation.
Id imagine that , of you have some scientific background and presented paper on your above 2 assertion areas, you wouldn't be treated like "grasshopper", youd be verbally eviscerated.

Well, Im not goind to be the first to exit politeness because you've spun off the edge. HAve a good life and keep up with your AP biology

I doubt youll make it that far. But still, try to answer the question because you know its answereable if you should put away that silly chip and use communication rather than invective

Wow! You've been studying this for 50 years? What would it be if you hadn't!?

If agriculture was invented 10,000 years ago in two or three narrow places in the world and for two or three species, do you think it would have had the time to influence world population 10,000 years ago?

The graph from wikipedia's Paleodemography entry indicates 5 (not 10) million people, hunter-gatherers, at that time immediately before agriculture.

This illustrates my point that in good times, the population of hunter-gatherers would have bounced back up quite rapidely (exponantially) from whatever low point they had to go through in bad times, up the ecological maximum for the species, its technology and its environment. A saturation point where localised conflict for resources WILL happen, especially for the best spots.

Because they DON'T!

How does that work, according to you? After a while, we have no genes anymore because all our genes are gone???

Wow! 7 pages devoted to the cause of existence, all while the original poster has been working on his/her tan, perhaps never to be heard from again.

Lots of interesting stuff, though.

As far as the original question, I always thought things existed because . . .

First, agriculture was invented more than 10,000 years ago. Second, the conditions which allowed for the invention of agriculture (something else which you apparently didn't understand) were large populations of game animals (antelope/gazelles in the middle east and deer in what we call China) and readily available, abundant forage foods. People didn't become sedentary because they one day said to themselves "Wow, let's invent agriculture!" They invented agriculture because their food resources were sufficiently reliable that they had already become sedentary and no longer needed to follow the game nor range widely for their forage foods. QED. Those conditions lasted for thousands of years before agriculture was invented, and those places in the world where they occurred (your modifier of "narrow" is not justified) determined the opportunity to domesticate plants and animals. You are, of course, also ignoring that h.n. was long gone from the scene by then.

You continue to ignore how labor intensive getting your sustenance was in periglacial conditions, which doesn't, of course, apply to the post-glacial period in which agriculture was invented. You are now ignoring the extent to which a sedentary life style reduces the potential effects of "the slings and arrows of outrageous fortune." If one must range widely to accomplish the necessary hunting and gathering (don't try to weasel on that one, you brought it up yourself), one incurs more risks. You continue to ignore the issues of stillbirths, infant mortality, childhood mortality and maternal mortality, in a much harsher climate. You continue to ignore how unlikely it is that h.n. would just stand around biting its collective nails and saying "Oh dear, oh dear" if h.s.s. were trying to exterminate them. Neanderthals were physically more robust and stronger than h.s.s., if you miss with your fancy spear-thrower the first time, you'd better run like hell.

Essentially, all you have had going for you all along is a jaundiced view of human nature and some completely unwarranted assumptions about the purposes to which the h.s.s. tool kit would have been put. Having been contradicted, you have resorted to sneers and insults, and the denigration of other people's sources, although i see you are willing to use Wikipedia when it suits your purposes. Like the verdict the Scots use in criminal trials, i pronounce your silly thesis unproven.

No, not much more than 10,000 years ago, therefore agriculture could not have impacted world demography 10,000 years ago. If you can find it in you to look at the graph I linked to, you will see that the demographic increase linked to agriculture only cranks in around 3000 BCE, once a large world population relies on agriculture to feed itself. Before that, the demographic impact is thought to have been marginal because too few people were involved in it.

Since around 5 million hunter-gatherers are estimated for that pre-neolithic period, it follows that hunter-gatherers can reach significant population levels, levels such that they get to compete with one another for space.

If not, why did man go into America? Why did he go out of Africa in the first pkace, if space was not getting tight at some point? Why walk into the unknown?

The idea that there was abundant game during some periods is exactly what I mentioned as the prerequisite for an exponential demographic growth of hunter-gatherers.

The work load of modern hunter-gatherers is significant but not that big that they can't fight wars, squirmishes and localised conflicts out of physical exhaustion... Modern and historically recorded hunters do/did fight with one another, occasionally. So there goes another one of your arguments.


So you realise that a hunter-gatherers' life can be risky? Good. A sedentary life too, when the other guys spot you, because you have more food and tools stored there to loot.


Like any species, we can grow in population size very rapidely, irrespective of the occasional stillbirth and more importantly, infant mortality. Note that most diseases came from animal domestication, so hunter-gatherers had far less diseases than modern humans have, but accidents and the occasional predators, yes. A woman can typically make 10+ children. If five, or even seven, die before adulthood, the population will still be growing. We are a resilient and highly successful species, not a bunch of loosers.

A word on my view of humans: I don't have a "jaundiced view", but a realistic view of my fellow humans. I have presented FACTS about humans having hunted many species to extinctions, and man being a wolf to man. An historian, such as yourself apparently, should know better than assume kumbaya dancers would carry the day for long in ANY HUMAN SOCIETY.

We should indeed devote some attention to climatic variations, which are THE main rival hypothesis for neanderthal's extinction. But these (at times) harsh conditions applued to sapiens and neanderthal alike.


The difference between the two weapon systems must have been significant. A few javelins are quickly thrown and lost. Arrows could be carried in much greater quantities. And indeed, Sapiens must have run faster than Neanderthal, because he was lighter... Another advantage.

That's a silly question.

Because it's ingrained deeply in our beings. We all want to know what's beyond.

Why then would be so many volunteers to space travel, even knowing that could be no return?

Bands of humans wander in the wilderness for the fun of it? That's a silly answer.

We know that sometimes bands of adolescent chimps roam around the wilderness breaking things and killing other animals, for no discernible reason other than fun.

Yeah but would adolescent chimps cross the ice-capped Bering straits out of fun?

The combination of a perfect chemical soup, plenty of water and free oxygen, a 70% or so nitrogen atmosphere,a high heat source - vulcanization, and electrical impulses - lightning. And, a long, long, long duration of time for proper maturation and evolution to take place. I've probably missed a few elements of nature that others can add. For some of you I will add the fickled finger of God, that can be included or excluded at will but in the end does not prevent the outcome we have today!

Adolescent chimps, yes, to expand their horizons and as a means for stretching their progenity.

Man would for sure, following the herds, for exploration and discovery, to obtain new lands (they weren't the first borned), religious persecution, to discover gold and silver, because they were criminals and/or alcoholics or other reasons that they couldn't stand to live in heavily populated areas.

My point entirely. Necessity is the mother of discovery. Crowded spaces at home plus the occasional series of bad years is what led bands of humans to wander around in the wilderness looking for greener pastures.

Along with many other things including to see what is on the other side of the mountain or just for the fun of it!

Granted

I suspect that in most cases hominids migrated as game migrated. The Bering land bridge was not ice-capped, once again, bullshit is being substituted for actual knowledge. It was not until well after the end of the two major glaciations that there was a concurrence of intelligence h.s.s. with a sophisticated too kit and plentiful game and fodder in temperate zones with a moderate climate. That was when h.s.s. stopped being migratory in certain areas (the middle east and north China, notably) and soon began domesticating plants and animals. Before 15,000 ybp, the conditions didn't exist, and neither did the sophisticated tool makers and users.

You either miss the implications of what i say, or you willfully warp them. The reference to stillbirths, infant mortality, childhood mortality and maternal mortality in a harsh climate has no relation to the disappearance of h.n. It's a reference to the questions of population density and population growth. Unlike your maundering on behalf of your unwarranted claim, i have a coherent argument to which i adhere.

Agriculture began at least a thousand years before 10,000 ybp, and possibly more. A thousand years of assured food in a moderate climate could have had (and very likely did) have a profound effect.

Take the Kebaran culture of the Levant(10.5-18Kybp) O16/O18 isotope ratios indicate it was cold , yet along the coastal plains (which, you must remember were dry land often hundreds of miles from the present shore lines. Settlements began. In the Kebarran is evidence of caches of wild grains like pre domestic emmer and ryes
Later cultures of 9500 to 12000 Ybp, l there is lots of evidence of "oases" ag communities (natufian culture). C14 of 12000 year . In this time period humans cultivated and developed strain of Emmer and einkorn.
Continued uplift of the Alps in the mid to late Pleistocene adjusted the climate from Continental arid to a MEditteranean moist in the Lower Danube through the LEvant(Bogger et al 2013). This whole area became very inviting climate wise and settlement was probably being pushed by Paleolithic and Neolithic real estate agents. Much of the artifact troves are missing because the areas that were settked and where "civilizations" began developing were inundated by Holocene sea level rise.
_____ For our young student poster who is unable to recognize the facts about population genetics. How about a question of an analogy using AMerind populations

There are several haplogroups unique to Amerinds. (ignore that the Amerind haplogroups have additional earlier haplogroup markers from earlier pre split-off populations)

All have increasing or severely decreasing %ages of their STRs and single nucleotide polymorphs wrt to the populations of the N and S American continents. In other words, as other haplogroups settled in the Americas, the percentages of the AMerind haplogroup were "Diluted" and did not occur because mating was non panmictic,

During the "ice ages," the energy equations were severe. Everyone had to expend maximum effort all the time to get enough food, to provide tools, to provide good clothing and footwear, to provide fuel for the winter. Nobody had any time to run around exterminating their neighbors. Your efforts not only had to repay the energy expended, but needed to produce a surplus to allow for packing fat for the winter.

Fifteen thousand years ago, that all changed. The energy equations became easier as there were plentiful food sources available at a much lower energy cost, and increasingly, less energy was required to prepare for and survive the winter. Game and forage food became plentiful enough that in a few areas, people became sedentary and were then able to domesticate plants and animals. Early modern humans lived and survived in harsh conditions, and it seems that they walked the knife-edge of extinction for thousands of years. But the very conditions which threatened them left them prepared to exploit the milder conditions which began to prevail 15,000 ybp, and our ancestors went from strength to strength and success to success.