Question

summarise with in-text citations:

1. Introduction

Human origins and the extinction of archaic populations have been the subject of intense debate in recent decades (e.g., Stringer and Andrews, 1988; Wolpoff, 1989; Brauer, 1992; Harpending et al., 1993; Lahr and Foley, 1998). Many hypotheses have been proposed for the extinction of such populations. Among the latter, research has focussed primarily on Neanderthals (e.g., Flores, 1998; Finlayson, 2004; Horan et al., 2005; Finlayson et al., 2006). The Neanderthal extinction took place mainly during Marine Isotope Stage 3 (MIS3), a period which has been considered highly unstable and which is characterized by conditions not existing in present-day environments (Stewart, 2005). Recent studies have suggested that climatic and environmental factors alone may have caused Neanderthal extinction, given that climatic stability was of crucial importance for their distribution (Finlayson and Giles-Pacheco, 2000; Stewart et al., 2003a; Stewart, 2004a, b). Climatic variability has been determined by using a number of proxies such as δ18O (Stringer et al., 2003; Burroughs, 2005). However, the hypothesis based on climatic and environmental factors alone has not been widely accepted, despite the fact that it has been discussed in depth. It is well known that Neanderthal populations were in fact able to successfully adapt to significant climatic fluctuations for approximately 300 ky (Finlayson, 2004). Their adaptability is likely to have involved a profound knowledge of their environment and the capacity to exploit different habitats, as well as seasonal mobility strategies, occupation of rich biotope areas (Finlayson, 2004; Finlayson et al., 2004), improved tool-making skills and better lithic resource management (Baena et al., 2005). Local extinctions and abandonment were, however, frequent in Neanderthal ecology (Trinkaus, 1995).

Neanderthal extinction is an especially difficult topic since it requires that relevant existing data from a multitude of disciplines be brought together and correlated with an appropriate methodological rigour on which consensus among researchers is highly problematic. The difficulties include: aspects of climatic influence on archaeological records, complex relationships between fossils and climatic conditions, incomplete nearby continental records, biased interpretations of climatic records, the sources of cultural features, an overemphasis on artefacts, rudimentary excavation techniques, dates obtained through a variety of methods and materials, dating and age models, and the coexistence of different underlying paradigms. The consequence of such a panorama is a highly fragile epistemology (Vega Toscano, 2005).

It has been suggested that the late Neanderthal populations survived in Southern Iberia. In general, Southern Iberia has been considered a “cul du sac” (Zilhao, 1996; Finlayson, 1999), playing a passive role in human/biological evolution. From this traditional point of view, the presence of relict taxa has been attributed to the position of the Southern Iberian Peninsula and its isolation from the major source of Euro-Asiatic faunal/floral input (Taberlet et al., 1998, Hewitt, 2000). However, the presence of species in this area could be related to its character as a climatic refugium (Finlayson, 2006) and to the fact that it is a biodiversity hotspot (Mota et al., 2002). In the late Pleistocene, three areas have been identified as major temperate and/or Mediterranean vegetation refugia during glacial periods: the Iberian, Italian and Balkan Peninsulas, (Bennett et al., 1991; Willis, 1996; Carrión et al., 2000; Tzedakis et al., 2002; Finlayson, 2006). “Cryptic” refugia have also been described, thus explaining the presence of Neanderthals in the Belgian Ardennes during the late MIS 3 (Stewart and Lister, 2001, Stewart et al., 2003b). The populations living in these refugia re-colonized central and northern Europe several times during the Late Pleistocene. It should be kept in mind that the capacity of refugia to continue carrying an ecosystem is a function of their specific location. The main characteristics of Southern Iberian refugia are their large scale, relatively low continentality, relative climatic stability, insolation and topography. These characteristics can only be reconstructed on the basis of representative local paleoclimatic records (Finlayson, 2006). In the case of the Southern Iberian Peninsula, the Algero-Balearic and Alboran basins provide particularly reliable climatic records (e.g., Cacho et al., 1999). Research has shown that the climatic conditions in this region were subjected to significant variations, mainly as a result of Glacial–Interglacial oscillations, Heinrich Events (HE), Dansgaard–Oeschner (D/O) stadials and interstadials (Moreno et al., 2005a).

In order to understand the paleoclimatic evolution in southern Europe and its relation to the aforementioned population refugia, a multi-proxy, high-resolution analysis was carried out in a marine sediment record from the western Mediterranean sea (WMS) (ODP core 975B-1H) (Fig. 1). This paper attempts to use Ba and Ba/Al ratios not only as paleoproductivity proxies, but also as an indicator of climatic stability. Mineral composition and trace element ratios have been used as paleo-proxies for paleoenvironmental reconstructions. K/Al and Mg/Al ratios, as well as quartz and clay minerals (e.g., illite and chlorite), were used to characterize river supply. Aeolian input has been characterized by Zr/Al and Ti/Al ratios. Trace elements sensitive to redox conditions (e.g., Fe, U, Co and Cr) have been used as paleo-redox and ventilation proxies. The results obtained have also been compared with other marine and continental climate records on regional and global scale in order to interpret the climatic conditions that may have affected Neanderthal populations.

Answer 1

Tntroduction Archaic populatioo es of Homo ase groupedl into bicad category of anchaic humans in the pewled Soo,ooo yean H ypically include Homo neandes thaleis Hlomo r hodesinsis, Homo heidel bergensis, Homo aniecesor Zn rec beginn cent decades the ornin anal extinction of thes e ochaic pepulation i's intenuly debated by many th as string naress 198, wolpoff 178 9 Broues 1792, Haapenoing et al 1223, lahr and fley 177 many hypotheses have also been pro pos eof bater reaserchers has foruiśed primarly on Neande thals Seientists ane (flores 1998 fina Hosan et al 2s finlayson et a1 2006 →In 2005 stecomt ,explai neol that neonden thal exlinedion tookplace mainly duin raine lsotope de is a period wher e climatic condlitions ane highly onstable. Recent studies have sugeested that -the climatic conditions may have caused neandeorthal erfinc ée because it ie an crutial importance in their distibution by finayson and iles pache co 20o0

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→Trac e elements to YedOX Conditions (fe, co, u, (v) rave been used as paleo-edo and ventidation proxles The results obtained have been cempared to othen masyine and continental climatia canditiors records on region al d l bal scale to kno the climatis conditians tha may have aktecte of Neanden thal population * The Neandexthal evtinetion began asto uno yo,00o eans in Evoupe 7 Recent studies i tobe 2o15, soggest thot they mod have been survived even tongen as recentiy → Hdpotheses on the fate ot the the Neanderthals include Viblence from encroac hing anatomicaly odenn humans , pasrasites and pathogers competitive. veplacement conpetrliue erclusiony extintion by Ye plac inten brecding oith carly modesun human Populati and failure o inability to adapt to climate chan