The earliest known species with what we would recognize as a face was an armored, beady-eyed prehistoric fish, according to a new paper in the journal Nature.
The fish, entelognathus primordialis (meaning “primordial complete jaw”), is the oldest known animal to have face-forming jaw and cheek bones comparable to those of today’s bony fishes and most terrestrial animals, including us.
An exclusive excerpt from chapter 6 of the new science/history/philosophy nonfiction book The God Problem: How A Godless Cosmos Creates, the new offering from the author of The Lucifer Principle: A Scientific Expedition into the Forces of History, Global Brain: The Evolution of Mass Mind from the Big Bang to the 21st Century and The Genius of the Beast: A Radical Re-Vision of Capitalism.
The God Problem: How A Godless Cosmos Creates is published on August 24 and is now available for pre-order on Amazon.
Meanwhile, in 1851, when he is thirty-one years old and walking, talking, and singing with Miss Evans, Herbert Spencer runs across an idea that will make him one of the biggest big-picture thinkers of all time. It is the idea that will keep Spencer a bachelor married to only one thing, his grand “synthesis.” Herbert Spencer will come across von Baer’s principle that cells in an embryo start out looking pretty much alike, then get more and more unique to their species. And more and more specialized in their function. Von Baer’s principle will change Spencer’s thinking. It will become the key to Spencer’s grand unification. And to his view of evolution. It will become Herbert Spencer’s equivalent to Newton’s gravity.
Yes, differentiation and the metaphor of the embryo will enter Herbert Spencer’s thinking three years after he comes to the Economist and one year after he begins to frequent John Chapman’s soirees. Says Spencer, “In 1851, I became acquainted with von Baer’s statement that the development of every organism is a change from homogeneity to heterogeneity.” And that acquaintance will push Spencer to till the soil in which Charles Darwin will plant a seed.
Once Herbert Spencer is exposed to von Baer’s work, the embryologist’s influence will show up almost instantly in Spencer’s work. It is the grand unifying principle that Spencer has been hunting for. It is another unifying principle to add to what Spencer has taken from George Henry Lewes’s explanations of Comte—the principle of evolution, and the principle that evolution constantly churns out something that Spencer calls “progress.” So von Baer’s principle of differentiation becomes central to Spencer’s 1851 first book, Social Statistics. The bigger and the more advanced the society, Social Statistics says, the more differentiation, the more specialization. The more “‘distinct classes’ and ‘special occupations.’” Large-scale societies unfold like embryos. They evolve like zygotes in the womb. Spencer publishes Social Statistics eight years before the publication of the book in which Charles Darwin premiers his theory of evolution, the Origin of Species. But Spencer, like the other habitués of Chapman’s get togethers, is already an evolutionary thinker, and he portrays the differentiation of human societies as an evolutionary process. Again, the word evolution has not appeared even once in Darwin’s only published book, his Voyage of the Beagle. But it appears one hundred times in Spencer’s second book, his 1855 Principles of Psychology. A book that comes out four years before Darwin’s On the Origin of Species.
Here’s how the combination of evolution and von Baer’s differentiation works. Says Spencer, in early societies, everyone did everything—hunting, fishing, and tool and weapon making. But as societies evolved, some men specialized in hunting and fishing and others became full-time tool or weapons makers—full-time spear and fishing hook experts. Way, way down the line, really advanced societies invented machines like railroad engines with hundreds of parts. So in an advanced society, there might be a specialist in Swindon who zeroed in on nothing but hand-making the setscrews for the steam engine, a task so exacting that one real-life machinist of Spencer’s day said “it almost made me sick.” Meanwhile other specialists assembled the engine, tested it, and ran it. And yet more specialists raised fruits, veg- etables, cows, and pigs and sent them into the city via railroad to feed the setscrew specialist. At the same time, even more specialists raised cotton in the American South, carded it and combed it in Manchester, then ran the resulting thread through Manchester’s weaving machines to make the set- screw maker’s clothes.
Hence it happens that a tribe of savages may be divided and subdivided with little or no inconvenience to the several sections.
OUR core physiology relies on subtle organic timers: disrupt them, and effects range from jet lag to schizophrenia. Exactly how and when life began keeping time is unclear, but a candidate for the original biological clock may solve the mystery.
Biological clocks are ubiquitous in nature, so the first clock should pre-date the evolutionary parting of the ways that led to modern groups of organisms. All the clocks found so far are unique to different groups of organisms, though. Not so the clock discovered by Akhilesh Reddy at the University of Cambridge and colleagues. In an enzyme called peroxiredoxin (PRX), they seem to have found a grandfather clock - one that is common to nearly all life.
PRX gets rid of poisonous, highly reactive oxygen (ROS), which is produced by oxygen-based metabolism. And the enzyme oscillates: it flits between an active and inactive state, depending on whether oxygen is bound to the active site. Using antibodies that bind only to the oxidised enzyme, the team found that PRX oxidation keeps cycling independently on a 24-hour cycle, even when organisms were kept in constant light or constant dark.
Moreover, they found this PRX cycle in mice, fruit flies, a plant, a fungus, an alga, bacteria and even in archaea - the most primitive of all cellular life (Nature, DOI: 10.1038/nature11088). That suggests PRX evolved early in life's history. A gene sequence analysis suggests it did so 2.5 billion years ago, during the Great Oxygenation Event (GOE) - a critical interval when the oxygen released by photosynthesis began to accumulate in the atmosphere.
Reddy thinks PRX protected primitive cells from ROS damage by surging when peaks in photosynthesis related to daylight temporarily bumped up levels of oxygen. "Initially this was externally driven," he says. Then PRX began oscillating spontaneously in anticipation of this load - thus becoming an independent daily clock. "Organisms with this anticipatory ability would be better adapted than organisms that merely 'reacted' to things as they happened," Reddy says.
Because all forms of life appear to dance to the metabolic rhythm of PRX oxidation, Reddy believes it pre-dates the other gene-related clocks that organisms carry.
It may even have driven their evolution. A gene-related clock, unique to cyanobacteria, appears to have evolved alongside PRX. What is more, another archaean that lives without oxygen and never had to deal with ROS has no PRX clock - and no circadian rhythms at all.
When PRX emerged 2.5 billion years ago, the Earth spun faster and a day lasted only 11 hours. "It will have adapted to the lengthening of the day-night cycle over time," says Reddy.
It may have done more than adapt - day lengths best suited to biological clocks may have coincided with times during which life made important evolutionary leaps. Ioannis Karafyllidis of the Democritus University of Thrace in Xanthi, Greece, has found that the cycling of the cyanobacterial clock resonates, or works most efficiently, at periods of 11 and 21 hours. These are the day lengths of the GOE and the Cambrian explosion of life, around 530 million years ago (Biosystems, DOI: 10.1016/j.biosystems.2012.02.008).
During the summer of 1963, when I was six years old, my family traveled from our home in Philadelphia to Los Angeles to visit my maternal relatives. I already knew my grandmother well: she helped my mother care for my twin brothers, who were only 18 months my junior, and me. When she was not with us, my grandmother lived with her mother, whom I met that summer for the first time. I come from a long-lived family. My grandmother was born in 1895, and her mother in the 1860s; both lived almost 100 years. We stayed with the two matriarchs for several weeks. Through their stories, I learned about my roots and where I belonged in a social network spanning four generations. Their reminiscences personally connected me to life at the end of the Civil War and the Reconstruction era and to the challenges my ancestors faced and the ways they persevered.
My story is not unique. Elders play critical roles in human societies around the globe, conveying wisdom and providing social and economic support for the families of their children and larger kin groups. In our modern era, people routinely live long enough to become grandparents. But this was not always the case. When did grandparents become prevalent, and how did their ubiquity affect human evolution?
Paleontologist Tim Flannery reminds listeners that while evolution functions as a competitive mechanism, the mutually dependent relationships that it produces should not be taken for granted. "The mechanism is pretty nasty and brutish," he says. "The legacy -- the thing it gives rise to -- is an enormously cooperative world."
Medía unos seis centímetros de largo, tenía el cuerpo blando como un gusano, diez pares de espinas robustas y probablemente apéndices articulados. Esa extraña criatura que se parecía más a una planta que a un animal pudo ser hace 500 millones de años el antepasado de los artrópodos modernos -animales con patas articuladas, como las arañas y los crustáceos-, el grupo biológico que ha tenido más éxito en el mundo animal. Los científicos han bautizado a esta forma de vida desconocida hasta ahora como el «cactus caminante», por su apariencia vegetal y los fuertes miembros sobre los que conseguía desplazarse. Su descripción aparece detallada por primera vez en la revista «Nature».
(PhysOrg.com) -- Rising carbon dioxide levels associated with global warming may affect interactions between plants and the insects that eat them, altering the course of plant evolution, research at the University of Michigan suggests.