Evolution

From ScienceDaily: Mitochondria, which exist within human cells but have their own DNA, need many different proteins to function — but the process of how they get these has never been imaged in detail. Now a study led by Dr Vicki Gold, of the University of Exeter, has shown that some ribosomes — the tiny factories of cells which produce proteins — are attached to mitochondria. This can explain how proteins are pushed into mitochondria whilst they are being made. The findings open new avenues for studying protein targeting and mitochondrial dysfunction, which has been implicated in diseases including cancer and neurodegenerative disorders such as Parkinson’s. “Proteins are responsible for nearly all cellular processes. The cell has to make a Read More ›

From ScienceDaily: Symbiotic relationships, which involve two different kinds of organism interacting with close physical contact, are common in nature. However, few prehistoric examples involve soft-bodied animals because they are normally not fossilized. Although fossils of the two species of marine worm, Cricocosmia jinnigensis and Mafangscolex sinensi, have been found before, these are the first reported examples to show other animals attached to them. The smaller worm-like guests, a new species named Inquicus fellatus, are up to 3mm long and attached at their bottom ends to the stiff skin of their hosts, with their feeding ends pointing away. espite the fact that Inquicus fellatus are attached to their host worms, there is little indication they were feeding by penetrating the Read More ›

As Stephanie Pappas writes, it’s much more complex than we might think: In 2013, researchers from the Integrated Ocean Drilling Program reported at the annual Goldschmidt Conference in Italy that they’d found microbes in 100-million-year-old sediments in the floor of the deep sea, according to the BBC. The microbes were reproducing once every 10,000 years, such a slow rate that scientists weren’t sure if they could really call the microbes “alive.” More. But surely that is a technicality. If they reproduced at all, they are alive. The issues she raises around very old organisms that have remained extant through cloning may be more meaty. We are getting somewhere if we can determine that something is definitely alive without necessarily coming Read More ›

Here: In this wide-ranging conversation, they discuss how the doctrine of creation makes sense of human dignity, racial equality, true peace and justice, purpose and meaning in life, and more. They also consider recent debates over the historicity of Adam and Eve. See also: Michael Chaberek: Darwinian theory is past its best-before date

From an op-ed at Nature: Scientists might have made a difference, had they protested against laws that now threaten what can be taught in our classrooms, argues Brandon Haught Haught is complaining about an academic freedom law in Florida that restricts the use of science courses for propaganda purposes: Advocates of the law were widely quoted as claiming that evolution is just a theory and that anthropogenic global warming is in doubt. It would have been invaluable if scientists at local universities had issued simple statements: yes, evolution is a fact; the word ‘theory’ is used differently in science from how it’s used in casual conversation; and the basics of human-caused global warming need to be taught. Perhaps authoritative voices Read More ›

Well, Columbia’s Rob Goodman thinks he did, at Aeon: Shannon’s ‘mathematical theory’ sets out two big ideas. The first is that information is probabilistic. We should begin by grasping that information is a measure of the uncertainty we overcome, Shannon said – which we might also call surprise. What determines this uncertainty is not just the size of the symbol vocabulary, as Nyquist and Hartley thought. It’s also about the odds that any given symbol will be chosen. Take the example of a coin-toss, the simplest thing Shannon could come up with as a ‘source’ of information. A fair coin carries two choices with equal odds; we could say that such a coin, or any ‘device with two stable positions’, Read More ›

From Ashley Yeager at the Scientist: A study of five far-flung human populations gives clues to adaptations to environmental pressures. The results revealed a strong link between population-specific DNA methylation, mRNA levels, and genotypes. However, the CpG sites where methylation occurred that had the highest degree of population specificity were more strongly associated with a local variation in a single nucleotide (SNP) compared with the association of mRNA levels with local SNPs. Population-specific DNA methylation patterns are therefore explained better by local genetic variants than population-specific expression levels, the team says. Because the DNA methylation variation appears to be under genetic control, it could greatly affect human adaptability. Fraser notes, however, that the consequences of methylation still aren’t clear. “It Read More ›

From U Chicago’s James Shapiro at Pub Med: Biological action in Read-Write genome evolution. Many of the most important evolutionary variations that generated phenotypic adaptations and originated novel taxa resulted from complex cellular activities affecting genome content and expression. These activities included (i) the symbiogenetic cell merger that produced the mitochondrion-bearing ancestor of all extant eukaryotes, (ii) symbiogenetic cell mergers that produced chloroplast-bearing ancestors of photosynthetic eukaryotes, and (iii) interspecific hybridizations and genome doublings that generated new species and adaptive radiations of higher plants and animals. Adaptive variations also involved horizontal DNA transfers and natural genetic engineering by mobile DNA elements to rewire regulatory networks, such as those essential to viviparous reproduction in mammals. In the most highly evolved multicellular Read More ›

From Bengt Autzen at the British Journal for the Philosophy of Science: Musing on Means: Fitness, Expectation and the Principles of Natural Selection How to measure fitness in the theory of natural selection? A fitness measure that has been proposed in both the biological and the philosophical literature is the expected relative reproductive success. The aim of this paper is to examine the relationship between expected relative reproductive success and future actual evolutionary success. Doing so will not only clarify the use of expected relative reproductive success as a fitness measure but also shed light on the role of fitness in the theory of natural selection. 1 Introduction 2 The Role of Fitness 3 Geometric Mean versus Expected Relative Reproductive Read More ›

We’ll probably never know what dinos were really like inthe sense that we can know what horses are like but we learn from Will Tattersdill at H-Sci-Med-Tech about the different ways we have understood them. Reviewing Dinosaurs Ever Evolving: The Changing Face of Prehistoric Animals in Popular Culture by Allen A. Debus, (1926–2009), he writes If you are interested in the history of dinosaurs in popular culture, Debus is an author you simply cannot ignore. He has written copiously on the “imaginative impact” of dinosaurs, and he is clearly on to something when he proposes to offer “an alternate history” of their evolution (pp. 265, 3)—a history written not across the geological ages of the Mesozoic (Triassic, Jurassic, Cretaceous) but Read More ›

Here: In Darwin’s scheme of things, the Victorian rich were the perfect expression of evolution. In perfecting itself, nature started with amoebas, and moved on through dinosaurs and flying lizards, fish, fowl and mammals until it came to the apes, so obviously like the poor savages of Tierra del Fuego or Papua New Guinea. Above the savages were the southern Europeans, above them the British and, at the top of the evolutionary pecking order, sat the great families of England, the Darwins, the Arnolds, the Huxleys and the Wedgwoods, who all intermarried and were obviously cleverer than anyone else. If these types of remarks had been made about any Victorian other than Darwin, the combox would not be Days of Read More ›

Supporting documentation See also: The second advent of the Royal Society’s evolution rethink last November?

From John S. Torday at Royal Society on the special issue edition on the (failures of) current Darwinism (aka the Modern Synthesis): The Modern Synthesis, merging population genetics and Darwinian evolutionary gradualism, was formulated in 1942. That was long before biologists learned about the Double Helix, the role of epigenetics in embryonic development, or the molecular bases for cell and developmental biology. All these developments are missing from neo-Darwinism. Even those who practice EvoDevo do not utilize cell biology to understand evolutionary mechanisms, defaulting to random mutation and natural selection. Much in evolutionary history can be understood by introducing knowledge of cell-cell signaling for pattern formation in the combined short-term ontogeny of the individual organism and the long-term phylogenetic history of Read More ›

And it’s only August. A special issue of Interface Focus on New trends in evolutionary biology: biological, philosophical and social science perspectives, organized by Denis Noble, Nancy Cartwright, Patrick Bateson, John Dupré and Kevin Laland is now available. The Royal Society journal is “devoted to a particular subject at the interface of the physical and life sciences.” Some of the articles in this edition are open access. One open access article is theoretical biologist Gerd B. Müller’s piece, Why an extended evolutionary synthesis is necessary: As can be noted from the listed principles, current evolutionary theory is predominantly oriented towards a genetic explanation of variation, and, except for some minor semantic modifications, this has not changed over the past seven Read More ›

Could two early life forms unite and pool information (endosymbiosis)? Lynn Margulis championed the idea but recently some have raised doubts. From Suzan Mazur at HuffPost: Kurland and Harish lay out their case in the current Journal of Theoretical Biology in a paper titled, “Mitochondria are not captive bacteria.” In it they note that “97% of modern mitochondrial protein domains as well as their homologues in bacteria and archaea were present in the universal common ancestor. . . . and were distributed by vertical inheritance.” But a big problem is that the subject has been surprisingly little researched. Mazur notes that endosymbiosis  champion Lynn Margulis told her, A fine scientific literature on this theme (symbiosis) actually exists and grows every Read More ›