Publish in OALib Journal
APC: Only $99
Past studies discussing the origins of agriculture have mainly emphasized changes in environmental and human-behavior factors as possible explanations for the shift from foraging to farming. This paper focuses on how increase in the biological fitness of both farmers and crops enabled the rapid evolution and success of farmers and agriculture. It is shown that the first plants under domestication achieved their superior fitness mainly as a consequence of some of their genetic and life-history traits. It led these species to be extensively integrated into human subsistence and eventually dominate the farmers’ fields. Concurrently, the first farmers gained their enhanced fitness by producing food surplus and by acquiring extra social prestige and power, while materializing the tendency to higher reproduction rate, and eventually to the expansion of farming populations. The unbreakable dependence between high fitness crops and high fitness man, namely their coevolution is a key issue and a promising research area in the understanding of the human story and the origins of agriculture.
In social networks, opinions diffusion often leads to relationships evolution. Then changes of relationships result in the change of balance degree of social system. We simulate the opinion diffusion on Barabasi & Albert (BA) network and Watts & Strogatz (WS) network to study the effects of the two types of networks, dynamical parameters and structural parameters on the balance degree of system. We employ the spectral analysis to quantify the balance degree of system before and after opinion propagation. The result reveals that it is very similar effect of BA networks and WS networks on it. However, it is opposite effects between dynamical parameters and structural parameters. The balance degree of system is proportional to the two dynamical factors (P,Q) at initial state and always inversely proportional to the two structural factors (< k >,Pne) at initial and convergence state.
The early white shark Carcharodon Smith, 1838 with the fossil Carcharodon auriculatus (Blainville, 1818) and the extinct megatooth shark Otodus Agassiz, 1843 with species Otodus sokolovi (Jaeckel, 1895) were both present in the European proto North Sea Basin about 47.8 - 41.3 m.y. ago (Lutetian, early Middle Eocene), as well as in the Tethys realm around the Afican-Eurasian shallow marine habitats. Both top predators developed to be polyphyletic, with possible two different lamnid shark ancestors within the Early Paleocene to Early Eocene timespan with Carcharodon (white shark line-age) and Otodus (megatooth shark lineage). Their sawblade teeth developed during the early Paleogene as the result of adaptation to feeding on various marine new rising mammals, coinciding with three main waves of evolutionary emergence of seals, sirenians, and whales in parallel with the evolution of these large predatory sharks. Megatooth sharks specialized in hunting whales and sirenians only on the coastal shelves of warm oceans and disappeared globally in the Pleistocene due to climate change and ocean cooling. The cold-water adapted early white sharks have survived until the present day with body temperate change adaptation in warm to temperate oceans and are proposed to have specialized on coastal seal hunting already50 m.y. ago.