Paleo-ENSO influence on African environments and early modern humans

Significance

Our results identify the prime driver of climate variation in Africa’s low latitudes over the past 620 ky—the key time frame for the evolution of our species. Warming and cooling of the tropical Pacific Ocean paced by insolation changes modulated the tropical Walker circulation, driving opposing wet–dry states in eastern and western Africa. We show that the effects of glacial/interglacial cycles were not the predominant source of environmental change in most of the continent. Africa’s environmental patchwork driven by low-latitude climate processes should therefore be a critical component in conceptual models of human evolution and early demography over the past 620 ky.

Abstract

In this study, we synthesize terrestrial and marine proxy records, spanning the past 620 ky, to decipher pan-African climate variability and its drivers and potential linkages to hominin evolution. We find a tight correlation between moisture availability across Africa to El Niño Southern Ocean oscillation (ENSO) variability, a manifestation of the Walker Circulation, that was most likely driven by changes in Earth’s eccentricity. Our results demonstrate that low-latitude insolation was a prominent driver of pan-African climate change during the Middle to Late Pleistocene. We argue that these low-latitude climate processes governed the dispersion and evolution of vegetation as well as mammals in eastern and western Africa by increasing resource-rich and stable ecotonal settings thought to have been important to early modern humans.

phys.org

Pan-African climate variability during the last ∼620 ky. (A) Orbital eccentricity (Left) and precession (Right) (59). (B) Average PC1 loadings derived from the pwPCA. (C) PC1 derived from the pwPCA. n = number of datasets used in each iteration. (D) Comparison between PC1 and the SST gradient (ΔSST; red line) between eastern Pacific Ocean Drilling Program (ODP) Site 806 (32) and western Pacific Ocean ODP Site 846 (33). Designation of El Niño– and La Niña–like conditions follows ref. 30. Breakpoints and their error bounds of PC1 (black boxes), ENSO (red boxes), and Earth´s eccentricity (gray boxes) are marked.

No evidence that the shift to farming made males and females more physically similar

> Scientists have proposed that males and females started to become more similar in size and shape after the origin of farming due to natural selection. However, a new evolutionary and genomic analysis by George Perry of Pennsylvania State University and colleagues, published in the journal PLOS Genetics, finds no evidence that this occurred.

> In the new study, the researchers tested this hypothesis by seeing if genetic variations linked to certain physical traits to a greater degree in either males or females have become more or less common during the last 3,000 years.

> However, only variations associated with one of the traits had become significantly more common—those associated with higher body fat in females.

> Overall, the findings contradict the longstanding idea that sex differences have become less pronounced due to natural selection since humans transitioned from hunting and gathering to agriculture...

Arctic rotifer lives after 24,000 years in a frozen state (phys.org)

Древние жители Монголии отправились в загробный мир на колеснице в сопровождении оленя

> Известно, что колесницы стали использоваться китайцами в эпоху Инь, приблизительно в XIV–XII веках до нашей эры, и им не предшествовали какие-либо местные формы колесного транспорта. Поэтому ученые предполагают, что иньцы узнали о колесницах от своих соседей, до которых они дошли через евразийские степи с Ближнего Востока.

какие учёные предполагают, что колесницы дошли до Китая с ближнего востока?

изображение колесницы в китайском привело к 車:

It is derived from a pictogram of a carriage seen from above. In the oracle bone script, there were large wheels on both sides and a sun shade on the top. Later, when Chinese characters were written vertically, the wheels on both sides were simply drawn in strokes and the loading area was marked with a 田 (OC *l'iːŋ). Therefore, it is important to understand that the current character, 車 (OC *kʰlja, *kla) is a vertical depiction of a carriage.

Etymology
Perhaps a loan from an Indo-European language because horse and chariot were introduced into China around 1200 BC from the West; compare Tocharian A kukäl, Tocharian B kokale (“wagon; cart”) (Mair, 1990; Bauer, 1994). An older variant survives in Mandarin 軲轆／轱辘 (gūlu, “wheel”) (Bauer, 1994). Alternatively, the word is a derivation by k-prefix from 舁 (OC *la, “to lift”) (Baxter and Sagart, 1998); compare the semantic parallel in Tibetan ཐེག་པ (theg pa, “vehicle; carriage”) (<to support; to carry; to lift).

и никакого ближнего востока

Character: 車
Modern (Beijing) reading: chē
Preclassic Old Chinese: k(l)a
Comments: In MC also read ćha, FQ 尺遮 (whence Mand. chē, Viet. xa), but this reading is rather recent (judging from rhymes, not earlier than Eastern Han) and must stem from some Old Chinese dialect. Viet. has also a colloquial loan from the same source: xe id. If the reconstruction is indeed *kla, one can think of an early borrowing from IE.

starling.rinet.ru

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(подробности)

🌍 Life in these star-systems could have spotted Earth

Pleistocene sediment DNA reveals hominin and faunal turnovers at Denisova Cave

Abstract

Denisova Cave in southern Siberia is the type locality of the Denisovans, an archaic hominin group who were related to Neanderthals. The dozen hominin remains recovered from the deposits also include Neanderthals and the child of a Neanderthal and a Denisovan, which suggests that Denisova Cave was a contact zone between these archaic hominins. However, uncertainties persist about the order in which these groups appeared at the site, the timing and environmental context of hominin occupation, and the association of particular hominin groups with archaeological assemblages. Here we report the analysis of DNA from 728 sediment samples that were collected in a grid-like manner from layers dating to the Pleistocene epoch. We retrieved ancient faunal and hominin mitochondrial (mt)DNA from 685 and 175 samples, respectively. The earliest evidence for hominin mtDNA is of Denisovans, and is associated with early Middle Palaeolithic stone tools that were deposited approximately 250,000 to 170,000 years ago; Neanderthal mtDNA first appears towards the end of this period. We detect a turnover in the mtDNA of Denisovans that coincides with changes in the composition of faunal mtDNA, and evidence that Denisovans and Neanderthals occupied the site repeatedly—possibly until, or after, the onset of the Initial Upper Palaeolithic at least 45,000 years ago, when modern human mtDNA is first recorded in the sediments.

Main

Denisova Cave consists of three chambers (designated Main, East and South Chambers) that contain deposits with stratigraphic sequences extending from the Middle Pleistocene to the Holocene epoch. The Pleistocene deposits have chronologies that have been constructed from the radiocarbon dating of bone, tooth and charcoal5 (to around 50 thousand years ago (ka)) and optical dating of sediments8 (to more than 300 ka). Optical ages for Main and East Chambers (Fig. 1a–c) can be aligned on a common time scale (Extended Data Fig. 1) but excavations are ongoing in South Chamber, where layers are only tentatively recognized. Mitochondrial DNA and nuclear DNA have been recovered from eight hominin fossils, enabling four to be assigned to Denisovans (Denisova 2, Denisova 3, Denisova 4 and Denisova 8), three to Neanderthals (Denisova 5, Denisova 9 and Denisova 15), and one to the child of a Neanderthal and a Denisovan (Denisova 11). However, there are too few fossils to enable the detailed reconstruction of the timing and sequence of hominin occupation, and the association of the early Middle Palaeolithic, middle Middle Palaeolithic and Initial Upper Palaeolithic assemblages identified at the site with specific hominin groups. Moreover, two Denisovan fossils (Denisova 3 and Denisova 4)—but no modern human remains—have been recovered from the Initial Upper Palaeolithic layers, so it is debated whether archaic hominins or modern humans created the associated ornaments and bone tools.

обзор на phys.org