In my fifth blog carnival hosting gig, I am honored and priviledged to present Carnival of Evolution #22. I’ve always considered this to be the most cerebral of the blog carnivals that I follow, and this month’s submissions have once again lived up to the high standards that I have come to expect – 26 submissions by 19 of the best evolution bloggers out there. I suggest we all pour ourselves a glass of brandy, settle into our armchairs, and enjoy an evening of thought-provoking erudition.
Human & Primates
Andrew Bernardin at 360 Degree Skeptic presents an evolutionary psychology piece in his post, Less Visible Forms of Social Power | 360 Degree Skeptic. Are humans an exuberantly affiliative species, like the bonobo, or is our nature essentially hierarchical? Or both? (Not to mention the impressively variety of forms that hierarchies can take.)
There’s a new kid on the blog, and Chadrick Lane jumps right into fray with his inaugural post at The Ancestral Mind. In Ancestral Mind in the Twitterverse: Discovering the information age through evolution, he recounts the magical feeling of visiting the Smithsonian Natural History Museum’s David H. Koch Hall of Human Origins, prompting him to ask “How is it that we have gone from a common ancestor with chimpanzees to a blogging, social networking, moon walking, singing and dancing species in just around 6 million years?” An impressive first post!
I was sure I’d receive multiple submissions dealing with the news of a potential new extinct human species, deduced from mitochondrial DNA sequence generated from a 40,000 year old finger bone found in a cave in a region of Siberia from which the remains of modern humans and Neanderthals have also been found. David Winter, however, enjoys a monopoly on this topic with his post, Does a forty thousand year old finger point to another human species? at The Atavism. David reminds us that inferring species boundaries is a tricky business, and the mtDNA sequences are not, in and of themselves, proof that the finger belonged to a member of a third human species. In fact, it might be a Neanderthal after all – how? David explains why.
At The Primate Diaries, Eric Michael Johnson discusses Cultural Transmission in Chimpanzees. The origin, maintenance, and transmission of cultural traits in human populations is both a fascinating and difficult subject for anthropologists. Though lacking obvious cultural traditions such as clothing or cuisine, nonhuman primates also have culture. An example is the Kibale Forest chimpanzees, which use sticks to get at honey in fallen logs, while Budongo Forest chimpanzees use chewed leaves as sponges to collect the same thing. Findings of a study to understand why some societies have more unique cultural traits than others, recently published in PLoS ONE, suggest this may have something to do with the number of females (with impressionable youngsters) present within a given society.
From Madeleine Begun Kane at Mad Kane’s Humor Blog comes this gem in her post, South African Pinot’s Too Pricey? Blame The Baboons:
Though South African wine can be fine,
There’s a threat to each grape growing vine.
Cuz baboons enjoy feeding
On grapes. Their fave eating
Is prized pinot noir — that’s the whine.
Adaptations
Jason Goldman at The Thoughtful Animal presents a post on a FIFTY YEAR LONG study of captive silver foxes in Russia in his post, The Russian Fox Study. It is his favorite study of animals EVER, perhaps because the experimental foxes were more eager to hang out with humans, whimpered to attract attention, and sniffed and licked their caretakers. They wagged their tails when they were happy or excited. Does that sound like Fido?
At Mauka to Makai, Kelsey Abbott discusses a male beetle (yeah, beetles!) with a penis so long and flexible that he has to sling it over his shoulder to keep it safe in her post Shouldering: Penis Extraction in Rove Beetles. As titillating as it sounds, the post is really about the behavioral adaptations that this male rove beetle has employed to deal with such extreme genitalia. The male is highly motivated (in the evolutionary sense) to follow a specific “penis extraction protocol” carefully, otherwise it will end up in a tangled mess (shudders!) and his chances with other ladies will be shot.
Zen Faulkes at NeuroDojo discusses a paper in PloS ONE by Sol et al. (2010) in his post Are big brains better for long trips? He notes that the authors found, as expected, that migratory birds tended to have smaller (and, thus, more energetically efficient) brains than non-migratory birds. However, what is the direction of causality? Read it and find out.
At Out walking the dog, Melissa Cooper discusses Mastodons in Manhattan: How the Honey locust Tree Got Its Spikes, noting that the formidible thorns of the honey locust tree are remnants of its co-evolution with giant herbivores – namely the browsing mastodons and woolly mammoths that roamed North America (including Manhattan) until somewhere between 6,000 and 11,000 years ago. The mastodons are gone, but the tree has not yet lost the adaptation, which now seemingly function only to puncture truck tires rather than deter proboscidean tongues.
Evolution of Sex
Genetic tests have revealed the secret sex life of a tiny poison dart frog species that lives in the Peruvian rain forests, GrrlScientist discusses at Living the Scientific Life in the post, Made for Each Other: Evolution of Monogamy in Poison Frogs. Remarkably, it turns out that these frogs are monogamous, but the reason is surprising: it’s all about the size of the pools that their tadpoles mature in. This is the best evidence yet that just a single cause can affect evolution of a major life history trait, e.g. a species’ mating system. GrrlScientist also discusses new research that shows evidence for cryptic mate choice in Gulf pipefish in her post, Size Matters — Bigger is Better, Even for Male Pipefish at Maniraptora: Tastes Like Chicken. This is supported by two observations. First, males that mate with larger (“more desirable”) females raise broods that have a higher survivorship. Second, embryo success in consecutive broods is negatively correlated. These observations show that males preferentially invest their limited resources into raising broods produced by “more desirable” females.
Microorganisms
At Skeptic Wonder, Psi Wavefunction recounts the excitement of getting to ramble on about protists for a whole twenty minutes in her post, Excavates and Rhizarians: A talk for phylogeny course. Presentations on each taxon included! She then admits a certain weakness for ciliates – not just for their insane cell and genomic organisation, or their bizzarely complicated morphology, or even their epi- and endosymbionts. No, what really tickles her about this group is that many of them WALK! See how in her post, Sunday Protist — Aspidisca: Walking ciliates with scrambled genomes.
Shuna Gould at Lab Rat looks at the evolution of two-component sensor (TCS) systems in her post, How The Animal Lost Its Sensor, and discusses a few reasons why they may no longer be present in animals. Widely used by bacteria to detect and respond to changes in both their outside and internal environments, but only nominally used by archaea and hardly at all by eukaryotes, it may be that TCSs originated in bacteria and spread by horizontal gene transfer to both archaea and eukaryotes. Once eukaryotes developed a nuclear membrane, no further transfers took place, while in bacteria TCSs continued to diversify.
Biology
“There’s more to eggshells than meets the eye,” says GrrlScientist at Living the Scientific Life in her post, presents Ancient DNA Isolated from Fossil Eggshells May Provide Clues to Eggstinction of Giant Birds. An international team of scientists just published a paper demonstrating for the first time that fossil eggshells are a rich source of ancient DNA. Using a newly developed method, the team isolated ancient DNA from a 19,000-year-old emu eggshell, an extinct species of giant moa, the enigmatic elephant bird from Madagascar, and two other extinct species. However, attempts to isolate DNA from a 50,000-year-old flightless Australian Thunderbird failed because the DNA was too fragmented. No – cloning these long-extinct birds is not likely.
Origins
At Evolving Thoughts, John Wilkins wonders how replicators can evolve (replicators being genes, or if not then any part or section of a process that meets Dawkin’s criteria of longevity, fecundity and copying-fidelity) in his post, Thermodynamics, and the origin of replicators « Evolving Thoughts. However, John takes exceptions with Dawkin’s view on the origin of replicators: “to posit that some molecule just acquired the capacity to replicate is to posit a scientific miracle. It’s a bit like suggesting that a molecule might just acquire the ability to act as a transistor. I do not like scientific miracles – they strike me as an admission of failure.”
Lucas at Thoughtomics admits he is an animal. In his post, On the Origin of Animals, he discusses a Nature paper published last month by a team of researchers that used the conserved expression of mircoRNAs to piece together information about the most recent common ancestor of all Bilateria – the great-great grandmother of almost all animals, expected to have lived somewhere between 600 and 550 million years ago. Since the evolution of Bilateria coincides with the evolution of many complex tissue types, microRNAs have the potential to be a great source of evidence for their evolution, and the team found microRNAs that were more or less specific for almost any tissue type present across the range of taxa studied. Move over HOX genes!
Evolutionary Theory
With a book titled, What Darwin Got Wrong, it might surprise you to learn that lead author Jerry Foder is a teacher of philosophy and not evolution. The premise of the book is that the “theory of natural selection” – as Foder calls it – cannot be true, but Bjørn Østman at Pleiotropy, in his post, The damned field of biology and the cursed theory of evolution, considers it to be nothing but “non peer-reviewed tripe”. Listen to the hour-long interview with Foder if you don’t have time to read his book and decide for yourself.
In addition to her unicellular musings above, Psi Wavefunction at Skeptic Wonder also argues In defense of constructive neutral evolution – Part I. This is the first of a 3-part post that addresses neutral evolution and its (mis)understanding compared to the flashier but probably overused explanations of adaptive evolution. “In short, selection acts probabilistically, not absolutely”.
Population dynamics of cheaters are interesting, since cheaters generally benefit when their numbers are low but don’t when they become too numerous. Lucas Brouwers at Thoughtomics discusses a paper that studied cheaters among bacteria in his post, Wolves, Bacteria and Cheaters. Population dynamics between cheaters and cooperators are much easier to study in prokaryotes than in animals, since genes and molecules involved in the cooperative behaviour are more easily identified and manipulated. Read what the authors of the study found…
At Culturing Science – biology as relevant to us earthly beings, Hannah Waters discusses two organisms that don’t fit into the 5-Kingdom classification that we all (at least the older among us) grew up with in her post, Photosynthetic Evolution: how 2 organisms gained or lost the ability to eat sunshine. The first is about microorganisms that were once photosynthetic — and thus evolved with the cyanobacteria and plants — but no longer go through photosynthesis. The second is about a sea slug that has developed the ability to photosynthesize, or harvest energy from the sun. Imagine the stories that all the other uncategorized protists out there have to tell!
At Deep Thoughts and Silliness, Bob O’Hara reviews a paper by Venditti et al. (2009, Nature) in his post, Branch Lengths and Species, that looks at the time between speciation events (i.e. the time a species spends as a single species, before it splits) as a way to infer something about the processes that lead to speciation. The authors conclude that speciation is a random event: there is nothing intrinsic to the species (such as its age) that makes it more or less likely to speciate. However, Bob has some methodological concerns about the paper – I’ll let him explain!
Alexander Bisignano at The Chromosome Chronicles discusses the potential that in silico models of evolution have over in vivo models in his post, Modeling Evolution in vitro and in silico. In the computer, DNA can be substituted for by self replicating computer code that undergoes changes/rearrangement. Resources can be simulated by computer memory or RAM. The actions of competing and reproducing are executed by self-replicating code as they compete to take up more of the computer’s memory. These in silico models of evolution allow for many generations to occur within a short period of time, thereby bypassing the main impediment to the study of in vivo models; however, whether these digital organisms are real beings will require more thought and ethical debate.
Eric Michael Johnson at The Primate Diaries discusses a paper by Harvard Medical School physician and researcher J. Wes Ulm that investigates the legacy of ideas that formed the basis of laissez-faire social Darwinism in his post, Social Darwinism and the “Cachet of the Cutthroat”. Despite their misuse by conservatives and economists for the past century and a half, Darwin’s ideas may be exactly what are needed to address some of our dire political and economic problems.
Politics & Science
“Embargoes do not serve the best interests of science or scientists because they deny access to embargoed literature to those people — science blog writers — who are most likely to invest the greatest amount of time and energy into writing the story accurately and in an engaging way for the public,” says GrrlScientist at Living the Scientific Life in her post Goddam, But I Hate Embargoes. “Since a fair number of science blog writers are scientists themselves, they have the knowledge to present these stories to the public and they also have a vested interest in making sure the science is being reported clearly and accurately. Even if embargoes are a necessary evil — and I remain unconvinced that they are — how they’re applied and dealt with is certainly not uniform, and pretending otherwise is just plain disingenuous.”
Announcements
GrrlScientist reminds us about her new twitter feed that announces science, environment, nature and medical blog carnivals to the public by providing links to the twitter feed and email for carnival hosts/managers to send URLs to. She is seeking community comments for how to make this feed work most effectively for this community.
I hope you’ve enjoyed this edition of Carnival of Evolution. The May edition of will be hosted at Evolution: Education and Outreach – posts can be submitted using this handy blog carnival submission form. You can find past issues at the home site and blog carnival index page. NOTE: hosts are needed for June and beyond – if you’ve never hosted a blog carnival, here’s your chance. If you have, you know how to do it, so why not share your expertise. Send an email to Bjørn if you’re interested.
Copyright © Ted C. MacRae 2010
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