 Your new post is loading...
Today's commercial coffee production is based on only a tiny slice of the genetic varieties that have grown since prehistoric times. ... In fact, there's a lot more genetic variety in this one little field at CATIE than there is in all the coffee plantations of Central America and South America — and that's a problem.
For many rural households ‘wild’ edible plants provide a substantial part of the daily diet. However, many are considered weeds by most agricultural scientists, and therefore undesirable.
The secrets of orchids that trick male insects into pollinating them by mimicking females are revealed by scientists.
Indirect estimates based on carbon dating point to intentional settlement by a large population. At least 1,000 Aboriginal founders first arrived in Australia some 50,000 years ago, a reconstruction indicates — numbers that could be evidence of an intentional migration rather than the accidental stranding of a few individuals at a time. The study also finds that the population was devastated during the latest Ice Age, but later rebounded. The prehistoric settlement of Australia has long been considered a simple story: a founding group of 150 people or fewer made it to the Australian mainland 50 millennia ago and grew to no more than 1.2 million by the time European settlers arrived in 1788. Debate focused on whether the founding population grew immediately after colonization or boomed later, in the past 5,000 years. To tease out a demographic signal from the past, Alan Williams, an archaeologist at the Australian National University in Canberra, amassed the most comprehensive radiocarbon data set ever put together for the continent, from both published and unpublished sources. He analysed the dates of 4,575 artefacts from 1,750 archaeological sites. Applying methods that others had developed to analyse a similar dataset from North American artifacts, Williams graphed the number of data points for each 200-year period, and made the assumption that for each given area, changes in the number of data points from one period to the next were a good indication of changes in population size — while correcting for the fact that some types of archaeological site can be lost over time owing to processes such as erosion. Assuming that the population would be between 750,000 and 1.2 million by the eighteenth century, he fit a smooth population curve to the data. According to Williams' curve, 1,000–2,000 founders would be necessary to reach the population that was in place when the Europeans arrived. After the founders arrived, the population would have stabilized at low levels, but crashed during the most recent Ice Age, around 20,000 years ago. “To quantify the impacts of the last glacial maximum — and see a 60% reduction in population — is quite horrendous,” says Williams. After the Ice Age, population growth rates began to increase in pulses, starting 12,000 years ago.
Via Dr. Stefan Gruenwald
The sulfur compounds of the Vidalia onion are extremely healthy -- harbouring the potential to lower your blood sugar, blood pressure and cholesterol, to thin your blood, to bolster your immune system and to fight cancer directly by helping your...
African origins of coffee can be trace to Ethiopia, where it has strong roots and offers a lesson.
The central role of grinding activities in the dietary practices of traditional agricultural populations can be approached from an ethnoarchaeological point of view. The comparison of ethnographic references raises the question whether the function and the socioeconomic context in which grinding slabs are used allow to assess issues related to conclusions drawn from archaeological contexts. Our discussion is based on the analysis of the manufacturing of grinding slabs, their use cycles and their social status in several Minyanka villages (Mali), providing useful references when examining the way in which archaeologists explain and interpret technological, functional and spatial observations. The typological and technical evolution and variability of querns results from a combination of several factors determined by the available raw materials, the skill of shaping techniques, the organisation of manufacturing and the transference of the function of grinding tools. But these factors alone cannot explain the encountered range of variation. Our study thus emphasises the very role of cultural aspects within these temporal and regional developments, and the impossibility of dissociating the use of a quern from its socio-economic context.
Via Dorian Q Fuller
Growing power seems to have a winning combo going. I underestimated what they are doing. Based on the information in these videos, IF true, then on 3 acres t...
Via Sarah LittleRedfeather Kalmanson
What Did the Amazon Look Like Before European Contact? - ScienceNOW
|
The vast majority of the coffee we drink is either Arabica or Robusta, but many factors -- including climate and how it is processed -- affect taste. The first article in this series on coffee covered its early roots and routes. Coffee has planted itself all over the globe from the forests of Africa to the Middle East, the Indian Ocean Islands, South and Southeast Asia and the tropical Americas. Nearly all the commercial coffee varieties (97%) that grow globally are derived from either Coffea arabica or Coffea robusta. But how do different coffee varieties emerge? What are some of the favored varieties? Before the green beans are roasted, what are the factors that affect quality? How can someone roast coffee beans at home?
The evolutionary significance of hybridization and subsequent introgression has long been appreciated, but evaluation of the genome-wide effects of these phenomena has only recently become possible. Crop-wild study systems represent ideal opportunities to examine evolution through hybridization. For example, maize and the conspecific wild teosinte Zea mays ssp. mexicana (hereafter, mexicana) are known to hybridize in the fields of highland Mexico. Despite widespread evidence of gene flow, maize and mexicana maintain distinct morphologies and have done so in sympatry for thousands of years. Neither the genomic extent nor the evolutionary importance of introgression between these taxa is understood. In this study we assessed patterns of genome-wide introgression based on 39,029 single nucleotide polymorphisms genotyped in 189 individuals from nine sympatric maize-mexicana populations and reference allopatric populations. While portions of the maize and mexicana genomes appeared resistant to introgression (notably near known cross-incompatibility and domestication loci), we detected widespread evidence for introgression in both directions of gene flow. Through further characterization of these genomic regions and preliminary growth chamber experiments, we found evidence suggestive of the incorporation of adaptive mexicana alleles into maize during its expansion to the highlands of central Mexico. In contrast, very little evidence was found for adaptive introgression from maize to mexicana. The methods we have applied here can be replicated widely, and such analyses have the potential to greatly inform our understanding of evolution through introgressive hybridization. Crop species, due to their exceptional genomic resources and frequent histories of spread into sympatry with relatives, should be particularly influential in these studies.
Here's an interesting paper for your students to consider. How does the evolution of languages compare to that of genes? It might help them to examine lots of familiar ideas more deeply. What does conservation mean? Is there evidence for seletion? Is the rate of change uniform or variable? Do languages show evidence of "horizontal word transfer"? Etc.
Via Mary Williams
Examination of 206 Neolithic and Chalcolithic bifaces from the southern Levant revealed that changes in form during the emergence of agropastoralism correlated with evolving land use practices, but new biface types also expressed altered social identities and perceptions of the environment. Nonfunctional groundstone pre-pottery Neolithic A (PPNA) bifaces seem to have served as social and status symbols, while flaked flint PPNA tranchet axes and chisels were used for carpentry rather than tree-felling. This pattern continued during the following early pre-pottery Neolithic B (EPPNB) period, but a new sharpening method, polishing, was used on a unique flint tranchet ax to strengthen its edge. By the MPPNB and LPPNB, heavier polished flint axes were used to clear forests for fields, grazing lands, wood fuel, and lumber. Sustainable forest management continued until the cumulative effects of tree-felling may have led to landscape degradation at the end of the PPNC. Adzes replace axes as heavy woodworking tools during the pottery Neolithic A (PNA) period, but by the PNB period, once again there are more carpentry tools than tree-felling bifaces. The trend is reversed again during the Chalcolithic, when the demand for fire wood, lumber, and cleared land seems to have increased during a time of emerging socioeconomic complexity.
Via Dorian Q Fuller
Examination of 206 Neolithic and Chalcolithic bifaces from the southern Levant revealed that changes in form during the emergence of agropastoralism correlated with evolving land use practices, but new biface types also expressed altered social identities and perceptions of the environment. Nonfunctional groundstone pre-pottery Neolithic A (PPNA) bifaces seem to have served as social and status symbols, while flaked flint PPNA tranchet axes and chisels were used for carpentry rather than tree-felling. This pattern continued during the following early pre-pottery Neolithic B (EPPNB) period, but a new sharpening method, polishing, was used on a unique flint tranchet ax to strengthen its edge. By the MPPNB and LPPNB, heavier polished flint axes were used to clear forests for fields, grazing lands, wood fuel, and lumber. Sustainable forest management continued until the cumulative effects of tree-felling may have led to landscape degradation at the end of the PPNC. Adzes replace axes as heavy woodworking tools during the pottery Neolithic A (PNA) period, but by the PNB period, once again there are more carpentry tools than tree-felling bifaces. The trend is reversed again during the Chalcolithic, when the demand for fire wood, lumber, and cleared land seems to have increased during a time of emerging socioeconomic complexity.
Via Dorian Q Fuller
Plants of all kinds were much beloved in ancient Egypt, and here is a selection from tiles, tombs and wall inscriptions. Can you identify them? Over the next few days I will put up a blog giving...
Via diana buja
A group of American scientists have been studying how to replicate properties found in certain types of bean leaves that can capture, or at least slow down, the pests.
The research on the well-preserved plant remains found in a Maya village that was destroyed by a volcano's fury will be presented at the annual meeting of the Society for American Archaeology.
Lede: "In fields from archaeology to zoology, an understanding of genomics is increasingly becoming a crucial skill. DNA sequencing and other genomic research techniques are used in scientific fields beyond medicine and genetics as tools to aid researchers in asking and answering new types of questions."
A friend of mine once recounted his evening of clubbing after taking magic beans, describing them as transporting him to an entirely new place. I ...
|
