Evolución de la Población 3. Evolución de la población. 3.1 Evolución histórica de la población. A lo largo de la historia la evolución de la población no ha llevado siempre el mismo ritmo de crecimiento que hay actualmente (Gráfico 3). Una vez establecidos estos cambios, la población se estanca, creciendo con altibajos y muy dependiente de las catástrofes naturales y humanas como epidemias, malas cosechas, guerras, etc. No es hasta el inicio de la edad moderna cuando la población comienza un ligero aumento, llegando a los seiscientos millones en el año 1600, siendo aun un crecimiento catastrófico. El segundo momento histórico importante para el crecimiento de la población lo encontramos durante la Revolución Industrial. Gráfico 3.
Nature's laws may vary across the Universe (PhysOrg.com) -- One of the laws of nature may vary across the Universe, according to a study published today in the journal Physical Review Letters. One of the most cherished principles in science - the constancy of physics - may not be true, according to research carried out at the University of New South Wales (UNSW), Swinburne University of Technology and the University of Cambridge. The study found that one of the four known fundamental forces, electromagnetism - measured by the so-called fine-structure constant and denoted by the symbol ‘alpha' - seems to vary across the Universe. The first hints that alpha might not be constant came a decade ago when Professor John Webb, Professor Victor Flambaum, and other colleagues at UNSW and elsewhere, analysed observations from the Keck Observatory, in Hawaii. "The results astonished us," said Professor Webb. "Another currently popular idea is that many universes exist, each having its own set of physical laws," Dr Murphy said.
7 milliards d'êtres humains dans le monde ! [infographie] Évolution de la population mondiale de 1800 à 2011. À gauche, le classement des sept pays les plus peuplés en 2011 et une estimation de ce classement en 2050. © Idé En animation : 7 milliards d'êtres humains dans le monde ! Sept milliards d'êtres humains peupleront la Terre ce 31 octobre. Comment se situe la France dans les statistiques de la population mondiale ? L'animation ci-dessous montre l'évolution démographique depuis 1800 jusqu'à aujourd'hui. Sept milliards d'être humains dans le monde en 2011, qu'en sera-t-il en 2050 ? Avec une espérance de vie mondiale qui augmente, le vieillissement de la population est inévitable. Après 2050, on estime que la progression se ralentira et que la population mondiale devrait ensuite se stabiliser entre 9 et 15 milliards. À voir aussi sur Internet Sur le même sujet
El neolític | La prehistòria El Neolític va ser una època en que els homes prehistòrics van descobrir moltes coses que els ajudaren a viure millor. Anem a conèixer com va anar canviant la seva vida. Quan comença El neolític comença fa 10.000 anys abans de Crist. La vida de l’home neolític Com que eren sedentaris, vivien en cabanes, i en petits poblats. L’alimentació Els homes i les dones del Neolític, s’alimentaven principalment de les plantes que conreaven: cereals (blat, civada, sègol, ordi…) llegums (llenties, ciurons, pèsols…); encara que no van deixar de recol·lectar fruits silvestres. Sergio de la Rosa i Qamar Les seves eines. La destral: L’utilitzaven per construir cabanes i estava fet de fusta i de pedra. La falç: S’utilitzava per tallar el blat i estava fet de fusta i dents Les pales: s’utilitzava per fer forats a la terra i estava fet de fusta. Aixada: S’utilitzava per cavar la terra i estava feta de pedra i de fusta. Molins de mà: s’utilitzava per moldre el gla i estava fet de dos pedres. Raúl Pérez Boyer
Adventures in Depression Some people have a legitimate reason to feel depressed, but not me. I just woke up one day feeling sad and helpless for absolutely no reason. It's disappointing to feel sad for no reason. Sadness can be almost pleasantly indulgent when you have a way to justify it - you can listen to sad music and imagine yourself as the protagonist in a dramatic movie. But my sadness didn't have a purpose. Essentially, I was being robbed of my right to feel self pity, which is the only redeeming part of sadness. And for a little bit, that was a good enough reason to pity myself. Standing around feeling sorry for myself was momentarily exhilarating, but I grew tired of it quickly. I tried to force myself to not be sad. But trying to use willpower to overcome the apathetic sort of sadness that accompanies depression is like a person with no arms trying to punch themselves until their hands grow back. When I couldn't will myself to not be sad, I became frustrated and angry. Which made me more sad.
Drone photos capture the dramatic inequality of Nairobi's neighborhoods — Quartz The global festival of music, art and culture doesn’t arrive in Johannesburg for another six months, but its expansion to the continent already marks a moment in Afropunk’s coming-of-age. About 12,000 people each day, from across Africa and around the world, are expected to gather starting Dec. 30 at the city’s Constitution Hill for a weekend of performances by Solange Knowles, Anderson .Paak & The Free Nationals, King Tha, Blk Jks, Laura Mvula, The Brother Moves On, Nakhane and Spoke Mathambo, among other established and emerging artists. Johannesburg is the latest locale for Afropunk, which debuted a dozen years ago in Brooklyn and has since expanded to Paris, Atlanta and London. “We go where we have community and we go where people want us,” says festival co-founder Jocelyn Cooper. “We’ve wanted to be on the continent, we love the culture in South Africa and we have a lot of contributors to our site who are there.”
Year-by-Year World Population Estimates: 10,000 B.C. to 2007 A.D. There are numerous world population estimates out there. These estimates can differ greatly from one to the next and some are more thorough than others. Finding estimates for the world’s population in the past 50 years is easy. The most “complete” set of estimates is provided by Atlas of World Population History (McEvedy and Jones 1978). Another good set of estimates comes from Population Growth and Land Use (Clark 1968). The League of Nations, the UN, and the US Census Bureau provide nearly complete estimates for each year in the 20th Century. Certain years in the estimates vary greatly between the different sets. Again, being accurate about population estimates from 2,000 years ago is impossible, but by taking all sets of estimates, creating an interpolation to fill in the gaps, and averaging all the estimates, we can get a more complete picture provided by the professionals. The following chart is comprised of 12 sets of estimates. Filling in the Gaps ). The Caveats Bibliography . U.S.
Bangkok Underwater - Alan Taylor - In Focus Heavy monsoon rains have been drenching Southeast Asia since mid-July, causing mudslides and widespread flooding. The deluge has now reached Bangkok, with rising water and associated problems affecting most of the city's 10 million residents. Prime Minister Yingluck Shinawatra said that parts of the capital could be inundated by up to 1.5 meters of water and remain flooded for up to a month. Around Bangkok, the second-largest airport has closed, food prices are soaring, clean water is becoming scarce, and the country is declaring a holiday from Thursday until Monday to allow people to evacuate. Use j/k keys or ←/→ to navigate Choose: Residents evacuate from their flooded town, north of Bangkok, on October 25, 2011. Flood waters surround an industrial complex in Bangkok, Thailand, on October 20, 2011. A television news reporter speaks to a camera in a waterlogged street near the Chao Praya river in Bangkok, on October 26, 2011.
ES RACÓ DES PT - EL RINCÓN DEL PT: L'esquelet escala 1/1 en castellà, català i anglès Como ahora nuestro hogar es aún más plurilingüe, las fichas para poder identificar los huesos las he hecho en castellano, catalán e inglés. Las tenéis con los recuadros en blanco y resueltas. A nosotros el esqueleto nos está dando para mucho… Primero hicimos nuestras siluetas en papel, tumbándonos sobre éste y repasando nuestro contorno. Después imprimimos y recortamos todos los huesos para empezar a montar nuestro esqueleto. Por último, pasamos a identificarlos y darles nombre en los tres idiomas y ahora seguimos entendiendo sus funciones y aprendiendo algunos detalles… ¿Sabías que…? Al nacer el cuerpo humano consta de 300 huesos pero al llegar a la edad adulta consta de 206 (sin contar dientes ni supernumerarios). Y en fin, que una puede extenderse y no acabar nunca… de momento nosotros aún no hemos acabado… cuando su sed de conocimiento empiece a aplacarse, probablemente seguiremos con el sistema digestivo, o el respiratorio… o ¡el que más les interese! ¿Te ha gustado?