The Genetic Gamesmanship of a Seven-Sexed Creature | Discoblog What could be better than two types of sexes? For one organism, the answer isn’t three, but seven! And to top it off, these seven sexes aren’t evenly distributed in a population, although researchers have now developed a mathematical model that can accurately estimate the probabilities in this crap-shoot game of sexual determination. Meet Tetrahymena thermophila, which in addition to its seven different sexes—conveniently named I, II, III, IV, V, VI, and VII—has such a complex sex life that it requires an extra nucleus. This fuzzy, single-celled critter has a larger macronucleus that takes care of most cellular functions and a smaller micronucleus dedicated to genetic conjugation. The other odd thing about this one-celled wonder is that the population of the seven sexes are skewed, leading Unversity of Houston researcher Rebecca Zufall and her colleagues to ask: What gives? Related Content: 80beats: What Makes a Boy Lizard? Image: Wikimedia Commons / Ayacop
The Human Body The Brain The human brain is the most complex and least understood part of the human anatomy. There may be a lot we don’t know, but here are a few interesting facts that we’ve got covered. Nerve impulses to and from the brain travel as fast as 170 miles per hour. Hair and Nails While they’re not a living part of your body, most people spend a good amount of time caring for their hair and nails. Facial hair grows faster than any other hair on the body. Internal Organs Though we may not give them much thought unless they’re bothering us, our internal organs are what allow us to go on eating, breathing and walking around. The largest internal organ is the small intestine. Bodily Functions We may not always like to talk about them, but everyone has to deal with bodily functions on a daily basis. Sneezes regularly exceed 100 mph. Sex and Reproduction As taboo as it may be in some places, sex is an important part of human life as a facet of relationships and the means to reproduce. Senses
Biologija.com.hr - Vijesti - Biologija - Zašto je nekih vrsta na Zemlji mnogo, a nekih malo? Na svijetu postoji više od 400.000 vrsta kornjaša (skupina kukaca), a samo dvije vrste tuatara ili premosnika, rođaka zmija i guštera, koji živi na sjeveru Novog Zelanda. Zašto evolucija stvara ''pobjednike',' kao što su sisavci i mnoge vrste ptica i riba, a zašto ''gubitnike'' i dalje je jedno od središnjih pitanja evolucijske biologije. Premosnici (Sphenodon) su jedini recentni rod reda Rhynchocephalia u razredu gmazova. Obitelj premosnika predstavljaju samo dvije vrste, Sphenodon punctatus (naslovna fotografija) i, još rjeđa, Sphenodon guntheri. Znanstvenici su pretpostavljali da je vrijeme glavni čimbenik koji utječe na broj vrsta - što su neke životinjske i biljne linije starije od ostalih, iz njih se mnogo više vrsta imalo vremena razviti. Druga teorija, da su neke skupine urođeno bolje ili lošije u proizvodnji vrsta, također ne objašnjava razlike u broju vrsta među glavnim živućim linijama biljaka i životinja. Izvori:
Rare and Precious Moments of Animal Life How interesting can animal life be is something which we can only guess. By looking these amazing photographs it seems that they have very funny and precious moments. Would you like to be monkey, or elephant, or maybe cat sometimes? Don’t worry if you do because this has happened all of us at least ones, for now enjoy these rare photos! Don Slish Animations {*style:<b>Animations and Interactive Tutorials Produced by Dr. Donald F. This animation shows the molecular mechanisms of the control of cell division by tyrosine kinases and the inhibition of this by p53, when there is slight DNA damage. Other animations: RER protein folding Hypoxic effects on dopamine release Metabotropic Receptor activating an ion channel Ionotropic Receptor Receptor Regulation (Extended) Receptor Regulation (Short form) Amphetamines, Ecstasy, Cocaine, and LSD mechanisms Insulin Receptor Mechanism Phosphatidylinositol Kinase and actin polymerization Toxin of the Neuromuscular Junction Summation (threshold) Summation Cell Crawling - retrograde flow of actin Cell Crawling APC control of Metaphase - Anaphase transition TNF activation of Apoptosis Cargo Vesicle moving on a Microtubule Vesicle I Astral molecular motor Astral II Molecular motors used in mitosis Molecular Motors A basic electrical circuit Basic Circuit
Brain, Brain Information Making sense of the brain's mind-boggling complexity isn't easy. What we do know is that it's the organ that makes us human, giving people the capacity for art, language, moral judgments, and rational thought. It's also responsible for each individual's personality, memories, movements, and how we sense the world. All this comes from a jellylike mass of fat and protein weighing about 3 pounds (1.4 kilograms). The brain's nerve cells are known as neurons, which make up the organ's so-called "gray matter." The cerebrum is the largest part of the brain, accounting for 85 percent of the organ's weight. The cerebrum has two halves, or hemispheres. Movement and Balance The second largest part of the brain is the cerebellum, which sits beneath the back of the cerebrum. The diencephalon is located in the core of the brain. The brain stem, at the organ's base, controls reflexes and crucial, basic life functions such as heart rate, breathing, and blood pressure.
Are you looking at me? Scientists discover bizarre flatworm with 60 eyes Flatworm is completely new speciesDiscovered in grassland near CambridgeBelieved to be of Antipodean descent By Mark Prigg Published: 13:14 GMT, 23 July 2012 | Updated: 08:36 GMT, 24 July 2012 It is one of the oddest creatures ever found. Scientists today revealed an entirely new species of flatworm. The unique animal has 60 eyes, all crammed into a body just 12mm long. The UK's first 60 eyed flatworm has been discovered on a nature reserve in Cambridge. The creature was found in grassland near Cambridge despite the area being described as the most 'documented place on the planet'. The 12mm worm was found by Brian Eversham, chief executive of the Wildlife Trust for Bedfordshire, Cambridgeshire and Northamptonshire. The peculiar invertebrate is thought to be of antipodean descent, but also a close relative of a species found in Northern Ireland called Kontikia Andersoni. Biologist Dr Hugh Jones, an expert in the field, believed it was a 'completely new, undescribed species'.
Birds and humans have similar brain wiring You may have more in common with a pigeon than you realise, according to research. It shows that humans and birds have brains that are wired in a similar way. A researcher from Imperial College London and his colleagues have developed for the first time a map of a typical bird brain, showing how different regions are connected together to process information. By comparing it to brain diagrams for different mammals such as humans, the team discovered that areas important for high-level cognition such as long-term memory and problem solving are wired up to other regions of the brain in a similar way. This is despite the fact that both mammal and bird brains have been evolving down separate paths over hundreds of millions of years. The team suggest that evolution has discovered a common blueprint for high-level cognition in brain development. Professor Murray Shanahan, author of the study from the Department of Computing at Imperial College London, says: