Cetacean Palaeobiology The archaeocetes are a paraphyletic group of primitive cetaceans that include the earliest, terrestrial 'whales'. The group consists of six families: Pakicetidae, Ambulocetidae, Remingtonocetidae, Protocetidae, Basilosauridae and Dorudontidae, although some scientists include the latter two in one single family Basilosauridae. The graph below shows, how these families are related to each other. Cetacean Evolution In order to understand the biology of the archaeocetes, it is important to first consider what sort of terrestrial animals cetaceans originally evolved from. The relations of early whales (archaeocetes) to artiodactyls and the two extant groups, odontoceti and mysticeti. But in 1994, Dan Graur and Desmond Higgins, two scientists working on cetacean gene sequences dropped a bombshell. Astragali of the Eocene protocetids Rodhocetus balochistanensis (left) and Artiocetus clavis (right), as compared to that of the pronghorn Antilocapra americana (centre). Protocetidae (Stromer 1908)
Biologists' discovery may force revision of biology textbooks: Novel chromatin particle halfway between DNA and a nucleosome Basic biology textbooks may need a bit of revising now that biologists at UC San Diego have discovered a never-before-noticed component of our basic genetic material. According to the textbooks, chromatin, the natural state of DNA in the cell, is made up of nucleosomes. And nucleosomes are the basic repeating unit of chromatin. When viewed by a high powered microscope, nucleosomes look like beads on a string. But in the Aug. 19 issue of the journal Molecular Cell, UC San Diego biologists report their discovery of a novel chromatin particle halfway between DNA and a nucleosome. While it looks like a nucleosome, they say, it is in fact a distinct particle of its own. "This novel particle was found as a precursor to a nucleosome," said James Kadonaga, a professor of biology at UC San Diego who headed the research team and calls the particle a "pre-nucleosome." These pre-nucleosomes, the researchers say, are converted into nucleosomes by a motor protein that uses the energy molecule ATP.
"Evolution is Fact" Grasshoppers frightened by spiders affect whole ecosystem Hebrew University, Yale researchers show how grasshoppers 'stressed' by spiders affect the productivity of our soil. How do grasshoppers who are being frightened by spiders affect our ecosystem? In no small measure, say researchers at the Hebrew University of Jerusalem and at Yale University in the US. A grasshopper who is in fear of an attacker, such as a spider, will enter a situation of stress and will consume a greater quantity of carbohydrate-rich plants -- similar to humans under stress who might eat more sweets. This type of reaction will, in turn, cause chemical changes in the grasshopper and in its excretions, affecting the ecosystem it inhabits. How does this happen? When the scared grasshopper dies, its carcass, now containing less nitrogen as a result of its diet change, will have an effect on the microbes in the ground, which are responsible for breaking down animals and plants. Research on this biological-ecological phenomenon was carried out by Dr.
A New Thermodynamics Theory of the Origin of Life Why does life exist? Popular hypotheses credit a primordial soup, a bolt of lightning and a colossal stroke of luck. But if a provocative new theory is correct, luck may have little to do with it. Instead, according to the physicist proposing the idea, the origin and subsequent evolution of life follow from the fundamental laws of nature and “should be as unsurprising as rocks rolling downhill.” From the standpoint of physics, there is one essential difference between living things and inanimate clumps of carbon atoms: The former tend to be much better at capturing energy from their environment and dissipating that energy as heat. Kristian Peters Cells from the moss Plagiomnium affine with visible chloroplasts, organelles that conduct photosynthesis by capturing sunlight. “You start with a random clump of atoms, and if you shine light on it for long enough, it should not be so surprising that you get a plant,” England said. England’s theoretical results are generally considered valid.
Newly Discovered Legless Amphibians Are Horrifying | Caecilian Family Discovered in India | Amphibians & Vertebrates Newly discovered legless amphibians live out their lives in underground burrows, tending their slimy pink young, which emerge from their eggs as miniature adults. If they sound like something out of a monster movie, they look it too: These creatures, part of a group of animals called caecilians, could pass for enormous earthworms. But they're actually vertebrates with backbones, more like salamanders or frogs. The discovery of new vertebrates is rare, especially outside of tropical rain forests, but the new caecilians come mostly from human-inhabited areas in northeastern India. To discover the new family, researchers led by the University of Delhi's S.D. Biju and his colleagues, who report their findings Tuesday (Feb. 21) in the journal Proceedings of the Royal Society B, dubbed the new family Chikilidae. Females of this family build nests for their young underground, laying eggs and coiling around them for the two to three months it takes the embryos to hatch.
Sea anemone: genetically ½ animal, ½ plant A team led by evolutionary and developmental biologist Ulrich Technau at the University of Vienna has discovered that sea anemones display a genomic landscape with a complexity of regulatory elements similar to that of fruit flies or other animal model systems. This suggests that this principle of gene regulation is already 600 million years old and dates back to the common ancestor of human, fly and sea anemone. On the other hand, sea anemones are more similar to plants rather to vertebrates or insects in their regulation of gene expression by short regulatory RNAs called microRNAs. These surprising evolutionary findings are published in two articles in the journal Genome Research. Our appearance, the shape we have and how our body works is, in addition to environmental influences, largely the result of the action of our genes. Simple organism with complex gene content Gene regulation comparable to higher animal model systems MicroRNAs are important for developmental processes in human…
First plants caused ice ages, new research reveals New research reveals how the arrival of the first plants 470 million years ago triggered a series of ice ages. Led by the Universities of Exeter and Oxford, the study is published in Nature Geoscience. The team set out to identify the effects that the first land plants had on the climate during the Ordovician Period, which ended 444 million years ago. Among the first plants to grow on land were the ancestors of mosses that grow today. The research suggests that the first plants caused the weathering of calcium and magnesium ions from silicate rocks, such as granite, in a process that removed carbon dioxide from the atmosphere, forming new carbonate rocks in the ocean. In addition, by weathering the nutrients phosphorus and iron from rocks, the first plants increased the quantities of both these nutrients going into the oceans, fuelling productivity there and causing organic carbon burial. The team used the modern moss, Physcomitrella patens for their study.
Tree of Life Web Project The Tree of Life Web Project (ToL) is a collaborative effort of biologists and nature enthusiasts from around the world. On more than 10,000 World Wide Web pages, the project provides information about biodiversity, the characteristics of different groups of organisms, and their evolutionary history (phylogeny). Each page contains information about a particular group, e.g., salamanders, segmented worms, phlox flowers, tyrannosaurs, euglenids, Heliconius butterflies, club fungi, or the vampire squid. ToL pages are linked one to another hierarchically, in the form of the evolutionary tree of life.
Scientists take first step towards creating 'inorganic life' Scientists at the University of Glasgow say they have taken their first tentative steps towards creating 'life' from inorganic chemicals potentially defining the new area of 'inorganic biology'. Professor Lee Cronin, Gardiner Chair of Chemistry in the College of Science and Engineering, and his team have demonstrated a new way of making inorganic-chemical-cells or iCHELLs. Prof Cronin said: "All life on earth is based on organic biology (i.e. carbon in the form of amino acids, nucleotides, and sugars, etc.) but the inorganic world is considered to be inanimate. "What we are trying do is create self-replicating, evolving inorganic cells that would essentially be alive. The cells can be compartmentalised by creating internal membranes that control the passage of materials and energy through them, meaning several chemical processes can be isolated within the same cell -- just like biological cells.
Evolution of life's operating system revealed in detail Posted June 30, 2014 | Atlanta, GA The evolution of the ribosome, a large molecular structure found in the cells of all species, has been revealed in unprecedented detail in a new study. Click image to enlarge In a new study, scientists compared three-dimensional structures of ribosomes from a variety of species of varying biological complexity, including humans, yeast, bacteria and archaea. The researchers found distinct fingerprints in the ribosomes where new structures were added to the ribosomal surface without altering the pre-existing ribosomal core, which originated over 3 billion years ago before the last universal common ancestor (LUCA) of life. Credit: Loren Williams/Georgia Institute of Technology. Around 4 billion years ago, the first molecules of life came together on the early Earth and formed precursors of modern proteins and RNA. The study was sponsored by the NASA Astrobiology Institute and the Center for Ribosomal Origins and Evolution at Georgia Tech. CITATION: Anton S.