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The timing and effect of the earliest human arrivals in North America 期刊论文
NATURE, 2020
作者:  Lorena Becerra-Valdivia;  Thomas Higham
收藏  |  浏览/下载:27/0  |  提交时间:2020/08/09

The peopling of the Americas marks a major expansion of humans across the planet. However, questions regarding the timing and mechanisms of this dispersal remain, and the previously accepted model (termed '  Clovis-first'  )-suggesting that the first inhabitants of the Americas were linked with the Clovis tradition, a complex marked by distinctive fluted lithic points(1)-has been effectively refuted. Here we analyse chronometric data from 42 North American and Beringian archaeological sites using a Bayesian age modelling approach, and use the resulting chronological framework to elucidate spatiotemporal patterns of human dispersal. We then integrate these patterns with the available genetic and climatic evidence. The data obtained show that humans were probably present before, during and immediately after the Last Glacial Maximum (about 26.5-19 thousand years ago)(2,3)but that more widespread occupation began during a period of abrupt warming, Greenland Interstadial 1 (about 14.7-12.9 thousand years beforead 2000)(4). We also identify the near-synchronous commencement of Beringian, Clovis and Western Stemmed cultural traditions, and an overlap of each with the last dates for the appearance of 18 now-extinct faunal genera. Our analysis suggests that the widespread expansion of humans through North America was a key factor in the extinction of large terrestrial mammals.


A Bayesian age model suggests that human dispersal to the Americas probably began before the Last Glacial Maximum, overlapping with the last dates of appearance for several faunal genera.


  
A process-based metacommunity framework linking local and regional scale community ecology 期刊论文
ECOLOGY LETTERS, 2020
作者:  Thompson, Patrick L.;  Guzman, Laura Melissa;  De Meester, Luc;  Horvath, Zsofia;  Ptacnik, Robert;  Vanschoenwinkel, Bram;  Viana, Duarte S.;  Chase, Jonathan M.
收藏  |  浏览/下载:10/0  |  提交时间:2020/07/21
Abiotic niche  coexistence  competition  dispersal  diversity  environmental change  functioning  stability  temporal  
Meta-population structure and the evolutionary transition to multicellularity 期刊论文
ECOLOGY LETTERS, 2020
作者:  Rose, Caroline J.;  Hammerschmidt, Katrin;  Pichugin, Yuriy;  Rainey, Paul B.
收藏  |  浏览/下载:5/0  |  提交时间:2020/07/14
Dispersal  fitness decoupling  germ line  group selection  soma  
Between a rock and a hard place: adaptive sensing and site-specific dispersal 期刊论文
ECOLOGY LETTERS, 2020
作者:  Nichols, Bethany S.;  Leubner-Metzger, Gerhard;  Jansen, Vincent A. A.
收藏  |  浏览/下载:6/0  |  提交时间:2020/07/06
Aethionema arabicum  dispersal  environmental variability  plasticity  sensing  
Experimental evidence of dispersal of invasive cyprinid inside waterfowl 期刊论文
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA, 2020, 117 (27) : 15397-15399
作者:  Lovas-Kiss, Adam;  Vincze, Orsolya;  Loki, Viktor;  Paller-Kapusi, Felicia;  Halasi-Kovacs, Bela;  Kovacs, Gyula;  Green, Andy J.;  Lukacs, Balazs Andras
收藏  |  浏览/下载:7/0  |  提交时间:2020/06/29
long-distance dispersal  freshwater  fish distribution  invasion  endozoochory  
Assessing metacommunity processes through signatures in spatiotemporal turnover of community composition 期刊论文
ECOLOGY LETTERS, 2020
作者:  Jabot, Franck;  Laroche, Fabien;  Massol, Francois;  Arthaud, Florent;  Crabot, Julie;  Dubart, Maxime;  Blanchet, Simon;  Munoz, Francois;  David, Patrice;  Datry, Thibault
收藏  |  浏览/下载:11/0  |  提交时间:2020/06/22
beta-diversity  demographic stochasticity  dispersal limitation  environmental filtering  path analysis  
The functional roles of species in metacommunities, as revealed by metanetwork analyses of bird-plant frugivory networks 期刊论文
ECOLOGY LETTERS, 2020, 23 (8) : 1252-1262
作者:  Li, Hai-Dong;  Tang, Linfang;  Jia, Chenxi;  Holyoak, Marcel;  Fruend, Jochen;  Huang, Xiaoqun;  Xiao, Zhishu
收藏  |  浏览/下载:8/0  |  提交时间:2020/05/25
Forest fragmentation  metacommunity  metanetwork  multilayer network  seed dispersal  species roles  
Internal state dynamics shape brainwide activity and foraging behaviour 期刊论文
NATURE, 2020, 577 (7789) : 239-+
作者:  Marques, Joao C.;  Li, Meng;  Schaak, Diane;  Robson, Drew N.;  Li, Jennifer M.
收藏  |  浏览/下载:6/0  |  提交时间:2020/07/03

The brain has persistent internal states that can modulate every aspect of an animal'  s mental experience(1-4). In complex tasks such as foraging, the internal state is dynamic(5-8). Caenorhabditis elegans alternate between local search and global dispersal(5). Rodents and primates exhibit trade-offs between exploitation and exploration(6,7). However, fundamental questions remain about how persistent states are maintained in the brain, which upstream networks drive state transitions and how state-encoding neurons exert neuromodulatory effects on sensory perception and decision-making to govern appropriate behaviour. Here, using tracking microscopy to monitor whole-brain neuronal activity at cellular resolution in freely moving zebrafish larvae(9), we show that zebrafish spontaneously alternate between two persistent internal states during foraging for live prey (Paramecia). In the exploitation state, the animal inhibits locomotion and promotes hunting, generating small, localized trajectories. In the exploration state, the animal promotes locomotion and suppresses hunting, generating long-ranging trajectories that enhance spatial dispersion. We uncover a dorsal raphe subpopulation with persistent activity that robustly encodes the exploitation state. The exploitation-state-encoding neurons, together with a multimodal trigger network that is associated with state transitions, form a stochastically activated nonlinear dynamical system. The activity of this oscillatory network correlates with a global retuning of sensorimotor transformations during foraging that leads to marked changes in both the motivation to hunt for prey and the accuracy of motor sequences during hunting. This work reveals an important hidden variable that shapes the temporal structure of motivation and decision-making.


  
Intensive farming drives long-term shifts in avian community composition 期刊论文
NATURE, 2020, 579 (7799) : 393-+
作者:  Oh, Eugene;  Mark, Kevin G.;  Mocciaro, Annamaria;  Watson, Edmond R.;  Prabu, J. Rajan;  Cha, Denny D.;  Kampmann, Martin;  Gamarra, Nathan;  Zhou, Coral Y.;  Rape, Michael
收藏  |  浏览/下载:15/0  |  提交时间:2020/05/13

Variation in vegetation and climate affects the long-term changes in bird communities in intensive-agriculture habitats, but not in diversified-agriculture or natural-forest habitats, by changing the local colonization and extinction rates.


Agricultural practices constitute both the greatest cause of biodiversity loss and the greatest opportunity for conservation(1,2), given the shrinking scope of protected areas in many regions. Recent studies have documented the high levels of biodiversity-across many taxa and biomes-that agricultural landscapes can support over the short term(1,3,4). However, little is known about the long-term effects of alternative agricultural practices on ecological communities(4,5) Here we document changes in bird communities in intensive-agriculture, diversified-agriculture and natural-forest habitats in 4 regions of Costa Rica over a period of 18 years. Long-term directional shifts in bird communities were evident in intensive- and diversified-agricultural habitats, but were strongest in intensive-agricultural habitats, where the number of endemic and International Union for Conservation of Nature (IUCN) Red List species fell over time. All major guilds, including those involved in pest control, pollination and seed dispersal, were affected. Bird communities in intensive-agricultural habitats proved more susceptible to changes in climate, with hotter and drier periods associated with greater changes in community composition in these settings. These findings demonstrate that diversified agriculture can help to alleviate the long-term loss of biodiversity outside natural protected areas(1).


  
The dental proteome of Homo antecessor 期刊论文
NATURE, 2020, 580 (7802) : 235-+
作者:  Abram, Nerilie J.;  Wright, Nicky M.;  Ellis, Bethany;  Dixon, Bronwyn C.;  Wurtzel, Jennifer B.;  England, Matthew H.;  Ummenhofer, Caroline C.;  Philibosian, Belle;  Cahyarini, Sri Yudawati;  Yu, Tsai-Luen;  Shen, Chuan-Chou;  Cheng, Hai;  Edwards, R. Lawrence;  Heslop, David
收藏  |  浏览/下载:29/0  |  提交时间:2020/07/03

Analyses of the proteomes of dental enamel from Homo antecessor and Homo erectus demonstrate that the Early Pleistocene H. antecessor is a close sister lineage of later Homo sapiens, Neanderthal and Denisovan populations in Eurasia.


The phylogenetic relationships between hominins of the Early Pleistocene epoch in Eurasia, such as Homo antecessor, and hominins that appear later in the fossil record during the Middle Pleistocene epoch, such as Homo sapiens, are highly debated(1-5). For the oldest remains, the molecular study of these relationships is hindered by the degradation of ancient DNA. However, recent research has demonstrated that the analysis of ancient proteins can address this challenge(6-8). Here we present the dental enamel proteomes of H. antecessor from Atapuerca (Spain)(9,10) and Homo erectus from Dmanisi (Georgia)(1), two key fossil assemblages that have a central role in models of Pleistocene hominin morphology, dispersal and divergence. We provide evidence that H. antecessor is a close sister lineage to subsequent Middle and Late Pleistocene hominins, including modern humans, Neanderthals and Denisovans. This placement implies that the modern-like face of H. antecessor-that is, similar to that of modern humans-may have a considerably deep ancestry in the genus Homo, and that the cranial morphology of Neanderthals represents a derived form. By recovering AMELY-specific peptide sequences, we also conclude that the H. antecessor molar fragment from Atapuerca that we analysed belonged to a male individual. Finally, these H. antecessor and H. erectus fossils preserve evidence of enamel proteome phosphorylation and proteolytic digestion that occurred in vivo during tooth formation. Our results provide important insights into the evolutionary relationships between H. antecessor and other hominin groups, and pave the way for future studies using enamel proteomes to investigate hominin biology across the existence of the genus Homo.