Science at Atheist Universe
Neuroscience. Sleepy Neurons Blur the Line between Sleep and Wakefulness. A few days ago, thanks to Dallas Gaytheist in the Animal Trivia Game thread, I learned that birds and some aquatic mammals sleep with only half of their brain in a "sleep state". Now scientists have found a similar phenomenon in rats, at least sleep-deprived rats, where some parts of the brain cortex, specifcally some neurons, "shut down" while the animal appears awake. In these pockets of napping neurons, neuronal patterns resemble those associated with non-rapid eye movement (NREM) sleep. "The rats were awake, but awake with a nice sprinkling of localized sleep in the cortex," says Guilio Tononi, a neuroscientist at the University of Wisconsin–Madison and lead author of the study. When the researchers tested the rats in a sugar-pellet-reaching task, performance declined in proportion to their neurons’ “offline” status, suggestive of how sleep-deprived people have trouble functioning.
Anthropology/Genetics/Human origins: Who is Homo sapiens and how do we relate to ancient humans? Make sure to bookmark the excellent, open access article in BioMed Central by two Berkeley scientists, Mason Liang and Rasmus Nielsen, written in the form of Q&A, answering questions about our genetic ancestry. Do we share DNA with Neanderthals and other members of the Homo genus? How do we know this? What techniques are used to study ancestry using DNA? What technical issues and difficulties are specific to working with ancient DNA? What level of certainty do we have at the moment that interbreeding has occurred between Homo sapiens and Neanderthals or Denisovans? These are subjects that come up time and again in the ever exciting field of human origins, this article has the answers to your questions.
Zoology: It was a busy and fun week for zoology, many of our stories this week are about invertebrates, these amazing earthlings that sometimes appear to be aliens from another planet to us simple mammals.
Mangrove box jellyfish always have four eyes on the sky
I wish the creationists or proponents of intelligent design would stop their merry-go-round of pseudoscience and took a moment to learn some biology. This animal, a Coelenterate, a jellyfish, a primitive little thing, has eyes with lenses, corneas, retinas, build from the same set of genes as our eyes are, and they have evolved their eyes, all 24 of them, to be on stalks, like a weighted ball dangling from a string. They detect the mangrove canopy by an eye type that is specialized to peer up through the water surface and that is suspended such that it is constantly looking straight up, irrespective of the orientation of the jellyfish. The visual information is used to navigate to the preferred habitat at the edge of mangrove lagoons. The upper lens of the specialized eye type is always pointing upwards top the sky, no matter how the jellyfish’s body is angled, even if it’s swimming upside-down. This adaptation helps the jellyfish navigate through the murky water of its mangrove home. Light patches filtering through the canopy attract small animals called copepods, which the jellyfish eats. This beautiful animal is beautifully adapted to keep its eyes on the canopy.
And we have two fascinating posts about insects!
Man discovers a new life-form at a South African truck stop
A really enjoyable article that describes how a German biologist, Oliver Zompro, stumbled upon a creature that looks like a living fossil, it is so different from other insects that it can actually be described as a separate Order. In phylogenetic classifications, Order is a very big branch; it is a huge deal to discover a new Order. Other people had seen the relatively common funny looking insects, now classified under the name Mantophasmatodea. When Zompro published his Science paper on the new Order in 2002, it was the first time since 1914 that a newly described living insect had proved unplaceable within a recognized order. These insects are wingless carnivores. Their closest phylogenetic relationships are likely to be cricket-looking insects called ice-crawlers) and also the stick insects. The blog article reads like an Indiana Jones adventure. Great read.
Fire ants walk on water as a super-organism
Argentinean fire ants form a "super-organism", a sort of raft as they float on water, an important adaptation for insects that live in areas prone to flooding. They seem to defy the laws of physics but in reality, they are taking advantage of the laws of physics: their waxy bodies repel water and they trap little bubbles as they weave their bodies into a raft; this way they can float for months if necessary.
The ants also come together to construct bridges, ladders and walls, but the rafts are the longest-lasting of these living structures.
LAST, BUT NOT LEAST: we’re back to BAD SCIENCE for this week’s special feature: Genetics and behavior: tired of the hype? I'm tired of seeing every single study on supposed connections between gene variants and human behavior hyped by the popular press, science TV shows, and sometimes the scientists who produced the data themselves. I cringe whenever I read about the :"gay gene", the "god gene", the "liberal gene", etc. I'm in the field of genetics/genomics, perhaps that's why I react so strongly to this sort of reports. Behavior is complex. Behavioral traits are not going to be transmitted by simple Mendelian genetics (one gene = one trait); many genes are likely to be involved, plus innumerable genetic factors, plus, epigenetics, plus cultural context, etc. I know it feels nice to simplify to feel comfortable about certain knowledge, but this tendency with regards to genetics and behavior is counterproductive and dangerous. Imagine if social policy was dictated buy flimsy data or oversimplifications.
Science bits and news from other sites:
Bacteria Grow Under 400,000 Times Earth's Gravity
This is probably not news to most people, but bacteria are tough little bugs! Shigeru Deguchi, a biologist at the Japan Agency for Marine-Earth Science and Technology, and his colleges, tested the ability of bacteria to grow in conditions of extreme gravity by replicating the hypergravity possible in asteroids and comets hitting the Earth, by using an ultracentrifuge. The scientists rapidly spun four species of bacteria—including the common human gut microbe Escherichia coli—to create increasingly intense gravity conditions. The bacteria clumped together into pellets as the gravity increased, but they continued to multiplied normally under thousands to tens of thousands of times Earth's gravity. Part of the microbes' ability to withstand hypergravity has to do with their sizes, Deguchi explained. The larger an organism, the more sensitive it is to gravitational forces. The new findings are consistent with an idea called panspermia, which says that life on Earth may be descended from alien microbes that hitched rides to our planet aboard ancient asteroids and comets. The abstract of the original article, published in the Proceedings of the National Academy of Science USA can be found here.
Sneaky Orchids Fake Infection to Fool Flies. An endangered slipper orchid in southwestern China fakes the look and smell of a fungal infection in order to attract one particular pollinator, the flat-footed fly. Black-brown spots mark the leaves of the orchid, mimicking the diseased look of a plant covered with fungus. The flowers even smell like they are rotting. When a fly lands on the orchid intending to dine on the infected patches, the deceived insect comes away hungry and covered in pollen. “This is the first time we’ve seen an orchid that uses both its flowers and leaves in the deception,” said orchid researcher Peter Bernhardt of Saint Louis University, co-author of a study published April 25 in the Proceedings of the National Academy of Sciences. “And it’s pollinated by a group of insects that have not been associated with flower pollination previously, to the best of our knowledge.”
What Makes a Queen Bee?. It’s long been known that a female bee’s place in the social order—whether she becomes a worker or a queen—depends not on her genes, but on whether she eats royal jelly. A study published in Nature found that royalactin, a protein found in royal jelly, is responsible for many of the physical differences that distinguish queens from the hoi polloi of the hive—and, surprisingly, that royalactin can even cause fruit flies to develop queen bee-like traits. This finding also shines light on how, at a cellular level, royal jelly turns bees into queens.
Social bonding in prairie voles helps guide search for autism treat.... Researchers at the Center for Translational Social Neuroscience (CTSN) at Emory University are focusing on prairie voles as a new model to screen the effectiveness of drugs to treat autism. They are starting with D-cycloserine, a drug Emory researchers have shown enhances behavioral therapy for phobias and also promotes pair bonding among prairie voles. Giving female voles D-cycloserine, which is thought to facilitate learning and memory, can encourage them to bond with a new male more quickly than usual. The results are published online and will appear in a future issue of Biological Psychiatry. "The prairie vole model has enabled us to learn about complex neural pathways in social areas of the brain," says senior author Larry Young, PhD. We believe these insights will be useful in identifying drugs that enhance social cognition and learning. Drugs with these properties, particularly when combined with behavioral therapies, may be beneficial in the treatment of autism spectrum disorders."