The earliest split in modern humanity was 100,000 years ago. What's interesting is that as a result of this split, populations within the Khoisan group should about as much genetic diversity as the rest of humanity does combined.
And that's including every other genotype within Africa. Once you eliminate the African populations from the pool it gets even narrower, to the point that the genetic differences between Eurasians, Amerinds, and Australian aborigines are remarkably small comparatively. On a related note, I remember going through the different Y-chromosome haplogroups of the world and was fascinated to find that the population group closest to Western Eurasians (including Europeans, Near Easterners, and East Indians) with Haplogroup R were the Amerinds, among whom the closely related Haplogroup Q is very common. In fact, the ancestral link through Y-chromosome between both groups appears stronger than that between East Eurasians and either of the two.
Did fist fighting change the course of human evolution? Protective buttressing of the human fist and the evolution of hominin hands. + Author Affiliations ↵* Author for correspondence (firstname.lastname@example.org) Received June 6, 2012.
Accepted September 24, 2012. The derived proportions of the human hand may provide supportive buttressing that protects the hand from injury when striking with a fist. Flexion of digits 2–5 results in buttressing of the pads of the distal phalanges against the central palm and the palmar pads of the proximal phalanges. Additionally, adduction of the thenar eminence to abut the dorsal surface of the distal phalanges of digits 2 and 3 locks these digits into a solid configuration that may allow a transfer of energy through the thenar eminence to the wrist.
FUNDING This research was supported by a grant from The National Science Foundation [IOS-0817782 to D.R.C.]. The Loom. Your hands are, roughly speaking, 360 million years old.
Before then, they were fins, which your fishy ancestors used to swim through oceans and rivers. Once those fins sprouted digits, they could propel your salamander-like ancestors across dry land. Fast forward 300 million years, and your hands had become fine-tuned for manipulations: your lemur-like ancestors used them to grab leaves and open up fruits. Within the past few million years, your hominin ancestors had fairly human hands, which they used to fashion tools for digging up tubers, butchering carcasses, and laying the groundwork for our global dominance today. We know a fair amount about the transition from fins to hands thanks to the moderately mad obsession of paleontologists, who venture to inhospitable places around the Arctic where the best fossils from that period of our evolution are buried.
A team of Spanish scientists has provided us with a glimpse of that story. Both fins and hands get their start in embryos. Rediscovering Life. Notes and Commentaries Toward a Biology Worthy of Life Stephen L.
Talbott RSS Feed for this page: This page serves as a portal introducing all new content for the “Biology Worthy of Life” project: BiologyWorthyofLife.org. Copyright 2014 The Nature Institute. You will typically find here notes and commentaries on the current biological literature. Contents Of Humans and Our Microbial Guests: A Dynamic and Living Balance (December 9, 2014) How Does an Organism Get Its Shape? Let’s Loosen Up Biological Thinking! Vladimir Solovyov on Sexual Love and Evolution (August 1, 2014) Symptoms: Notes from the biological literature (2) (July 3, 2014) Psyche, soma, and the unity of gesture — Part 2 of “From bodily wisdom to the knowing self” (June 10, 2014) Three questions for intelligent design theorists (May 15, 2014) Biology’s shameful refusal to disown the machine-organism (April 24, 2014) Symptoms: Notes from the biological literature (1) (March 31, 2014) Who are you and who am I and who are we?
Abstract: Life Sciences. SCIENCE. Scientific Ideas for the Garbage Dump - On Science Blogs. Hello there!
If you enjoy the content on On Science Blogs, consider subscribing for future posts via email or RSS feed. These scientific ideas will drive you crazy Much has been made of this year’s question at John Brockman’s Edge, generally described as an online salon. Brockman asked for recommendations about which scientific ideas should be retired, and some 170 salonists replied. Dennis Overbye plucked up a few proposed discards for consideration at Out There, concluding, “No matter who you are, you are bound to find something that will drive you crazy.” I guess being driven crazy explains Wesley Smith’s fulminations at National Review.
Which poses the question: Just who is the ideologue here? But here’s a science Fun Fact that turned into a Tangled Tale. Of a particularly stinky sort, I would add. You can read the blow-by-blow on Hauser at the indispensable Retraction Watch. More scientific ideas for the trash heap Science is (not) self-correcting.
New Research Info. The 100 Top Science Stories of 2010. Ernest Rutherford’s Nucleated Century. The critical discovery in this atomic model emerged a century ago in a talk before the Manchester Literary and Philosophical Society in March 1911 and a paper published soon after in the Philosophical Magazine.
Both were by Ernest Rutherford, who had won the 1908 Nobel Prize in Chemistry in part for his discovery of the alpha particle, which he later proved was the nucleus of a helium atom. By 1911, scientists had already measured the charge and mass of an electron. But no one was sure how the atom was structured. Among his endless contributions to atomic theory, Rutherford explained a curious phenomenon. When fired at an extremely thin sheet of gold foil, some alpha particles scattered at surprising angles. A few even bounced straight back at the observer, which Rutherford said was as unexpected as firing a cannon shell at tissue paper and having it come back and hit you. Child creates molecule that could be used for energy storage or explosives. Prof.
Robert Zoellner, with a model of the molecule created by ten year-old Clara Lazen I don't know about other people, but when I was a child, I was inventing things such as a musical instrument made out of a folded piece of cardboard and some rubber bands. Ten year-old Clara Lazen, however, has done something a little more noteworthy. The fifth-grader from Kansas City, Missouri, built a model of a molecule that is new to science.
If the molecule itself were to actually be created, it could possibly be used for energy storage, or in explosives. Lazen built the model out of balls representing oxygen, nitrogen and carbon atoms, as part of a science exercise at Border Star Montessori School. Dubbed tetranitratoxycarbon, Clara's molecule contains the same combination of atoms as nitroglycerin, and according to Zoellner, could potentially be used to store energy or create a large explosion. Source: Humboldt State University via Skepchick About the Author Post a CommentRelated Articles. On Truth & Reality: Philosophy Physics Metaphysics of Space, Wave Structure of Matter. Famous Science Art Quotes. JST Virtual Science Center.
Science. The more we understand about science and its complexities, the more important it is for scientific data to be shared openly.
It’s not useful to have ten different labs doing the same research and not sharing their results; likewise, we’re much more likely to be able to pinpoint diseases if we have genomic data from a large pool of individuals. Since 2004, we’ve been focusing our efforts to expand the use of Creative Commons licenses to scientific and technical research. Science Advisory Board Open Access The Scholars’ Copyright Project Creative Commons plays an instrumental role in the Open Access movement, which is making scholarly research and journals more widely available on the Web.
We’re also expanding Open Access to research institutions. We’ve created policy briefings and guidelines to help institutions implement Open Access into their frameworks. Open Data At Creative Commons, we believe scientific data should be freely available to everyone. Learn more.
CHEMISTRY & PHYSICS. Physics and biology sites. Otherwise, there are a quite a lot of sites out there covering physics and biology at this level, but my impression of them is that they would be good for revision, but not so good if you were struggling to understand something in the first place.
If you want to find what is available a Google search on "a level" physics or "a level" biology should throw up a good selection. If you are doing some other exam - IB, for example, or Scottish Highers - you could try searching for these in a similar way, but it would still be worth looking for A level sites (and vice versa for A level students). Physics, especially, is probably a difficult subject to explain simply on the web, because so much of it is mathematical. Calculations are very hard to do well on the web. Personally, as soon as some maths appears in a chemistry web site, I switch off - and that's despite my having written a chemistry calculations book.
Return to questions list . . . Go to Main Menu . . . Specials archive : Nature. Prokaryotes, Eukaryotes, & Viruses Tutorial. Chemistry - few periodic rules to rule them all :) Interactive Concepts in Biochemistry - Interactive Animations. Organic Chemistry Animations ChemTube3D. CHEM 1211 COURSE CONTENTS. CHEM 1151 LECTURE - GPC, Dunwoody Most of the lectures will be based on the PowerPoint notes below (~70%), and these will be reinforced with some additional board work (~30%).
Chapter 1 MEASUREMENTS 1. Chemistry and Chemicals 2. 4. 6. 8 Writing Conversion Factors 9. Chapter 2 ENERGY and MATTER 1. 4. 6. . - First Exam covers Chap. 1 & 2 For samples of old exams, scroll down to the end of Chap 10. on this page . Chapter 3 ATOMS and ELEMENTS 1. 4. 7. Chapter 4 NUCLEAR CHEMISTRY 1. 4. 6. Chapter 5 COMPOUNDS AND THEIR BONDS 1. 4. 7. 9.
Chapter 6 CHEMICAL REACTIONS and Quantities 1. 4. 7. 9. . - Third Exam covers Chap. 5 & 6 Chapter 7 GASES Chapter 8 SOLUTIONS 1. 4. 6. . - Fourth Exam covers Chap. 7 & 8 Exam #4 (Take-Home) will be available at this place from 5:00 PM, July 12th, 2013. Click on the Take-Home above. Chapter 9 REACTION RATES AND CHEMICAL EQUILIBRIA 1. 3. 5.
Chapter 10 ACIDS and BASES 1. 4. 6. . - Final Exam is comprehensive covering Chap. 1 – 9 Old Sample Exams: Test #1 , Test #2, Test #3, Test #4. 1. Virtual Laboratory: Thermodynamic Equilibrium. Here is a snapshot of the applet. Read the instructions and then go to the links at the bottom of this page to activate various kinds of experiments that can be done with this applet. This applet is designed to simulate the diffusion process which occurs when gases of different temperatures are mixed. To activate the mixing click one time on the red vertical bar that separates the two chambers. After a few moments, the bar will turn green and the gases will start to mix and share their energy. The counters in the respective chambers indicate the number of particles in that chamber. Click chemistry. Click chemistry, a term coined by K.
Barry Sharpless in 1998, was first fully described by K. Barry Sharpless, Hartmuth Kolb, and M.G. Finn of The Scripps Research Institute in 2001 and describes chemistry tailored to generate substances quickly and reliably by joining small units together. Click chemistry is not a single specific reaction, but was meant to mimic nature, which also generates substances by joining small modular units. A desirable click chemistry reaction would: The process would preferably: have simple reaction conditionsuse readily available starting materials and reagentsuse no solvent or use a solvent that is benign or easily removed (preferably water)provide simple product isolation by non-chromatographic methods (crystallisation or distillation) Explanation Proteins are made from repeating amino acid units, and sugars are made from repeating monosaccharide units.
Azide alkyne Huisgen cycloaddition Applications References Understanding Chemistry - interesting links.
Read full article Continue reading page |1|2|3|4|5|6 Read more: 13 more things that don't make sense 1 The placebo effect Don't try this at home. Several times a day, for several days, you induce pain in someone. This is the placebo effect: somehow, sometimes, a whole lot of nothing can be very powerful. So what is going on? Benedetti has since shown that a saline placebo can also reduce tremors and muscle stiffness in people with Parkinson's disease.
Axis of evil Radiation left from the big bang is still glowing in the sky – in a mysterious and controversial pattern Dark flow Something unseeable and far bigger than anything in the known universe is hauling a group of galaxies towards it at inexplicable speed Eocene hothouse Tens of millions of years ago, the average temperature at the poles was 15 or 20 °C. Fly-by anomalies Hybrid life Morgellons disease. NASA video crushes 2012 Mayan apocalypse myth. Scientists at NASA's Jet Propulsion Laboratory have put out a new video to address false claims about the "Mayan apocalypse," a non-event that some people believe will bring the world to an end on Dec. 21. In the video, which was posted online on March 7, Don Yeomans, head of the Near-Earth Objects Program Office at NASA/JPL, explains away many of the most frequently cited doomsday scenarios. [See video] Addressing the belief that the calendar used by the ancient Mayan civilization comes to a sudden end in December 2012, and that this will coincide with a cataclysmic, world-ending event, Yeomans said: "Their calendar does not end on December 21, 2012; it's just the end of the cycle and the beginning of a new one.
It's just like on December 31, our calendar comes to an end, but a new calendar begins on January 1. " He added that there is zero possibility of a NASA cover-up. "Then we have planetary alignments," Yeomans said. Related on Life's Little Mysteries. 6 Insane Discoveries That Science Can't Explain.