Which South American vulture can have a wing span of up to 3 meters and a body weight of up to 13 kilos?

Vulture | San Diego Zoo Animals & Plants San Diego Zoo Animals & Plants FAMILIES: Cathartidae (New World) and Accipitridae (Old World) GENERA: 14 SPECIES: 23 ABOUT What makes a vulture? They may not be the prettiest birds of prey, but the world would be a smellier place without vultures!  All vultures have a wide wingspan, which allows them to soar for long periods of time without flapping so much as a feather while looking for carrion to eat. They all have a sharp, hooked beak for ripping apart meat. Vultures are large compared to other birds. Their bald head and neck serve a useful purpose, allowing vultures to steer clear of infection and tangled feathers when eating decaying meat. A strong immune system allows vultures to eat rotting and possibly infected meat without getting sick. These unusual birds are divided into two groups: New World vultures, which are from North, Central, and South America; and Old World vultures, which live in Africa, Asia, and Europe. New World vultures have a distinctive bald head, an adaptation that helps reduce the risks of disease, because bacteria could become lodged in feathers, while the bald head and neck may be disinfected by the sun’s rays. New World vultures have nostrils that are long and horizontal, with a space between them. They do not have a voice box, so they cannot make any sound except hisses and grunts. New World vultures don’t build nests; instead, they lay their eggs in holes on high rocky surfaces or in tree cavities.  Some examples of New World vultures are turkey vultures, black vultures, king vultures,  California condors , and  Andean condors .  Old World vultures look like their eagle and hawk relatives. They have large, grasping talons, a voice box to vocalize with, and build nests made of sticks on rocky platforms or in trees. Old World vultures have also been around longer than the New World vultures. They have stronger feet than the New World vultures, which have feet that are not designed for grasping, and large, broad wings that allow them to stay aloft for most of the day, and a large, powerful beak with a hooked tip.  Some other examples of Old World vultures are Himalayan, Egyptian, hooded, Indian black, and palm-nut vultures, and Egyptian or Eurasian griffons. Although New World vultures are unable to make more than hissing and grunting sounds, Old World vultures can be quite vocal when feeding at a carcass, making lots of grunts, croaks, screeches, and chatter. White-backed vultures croak plaintively or squeal like pigs during a meal. Bearded vultures scream while rolling and twisting in flight during courtship. Not many animals threaten vultures. Covered as they are with bacteria, they would make most predators sick if eaten. Other scavengers may threaten the vulture, mainly to get better access to a shared carcass. Vultures tend to gorge themselves, often to the point of being unable to fly. If they feel bothered as they stand about digesting their food, they simply regurgitate to lighten the load and fly off. Many people look at the vulture as a sign of death, but some cultures admire the birds. Ancient Egyptians connected the Egyptian griffon to their goddess Nekhbet, guardian of mothers and children. Griffon images are found in early Egyptian paintings and drawings and even had a place on the crown of the pharaoh, alongside the cobra. In Native American culture, California condors are important in mythology and burial rituals.  Vultures are also important in India, as they help remove dead animals without spreading disease. In other parts of Asia, religious and cultural traditions call for the carcasses of domestic animals to be left out for “disposal” by vultures. In some regions, even human remains are left out for the vultures prior to burial.  Vultures may not have the cleanest job, but you will never hear them complaining! HABITAT AND DIET Home is where the food is! Vultures are pretty flexible when it comes to their habitat, as long as there is food, although you won’t find them in Australia, polar regions, or most small islands. They are pr


Which part of a beetle's body is a skeleton?

Insect Parts - Elementary Science Lessons & Tests - My Schoolhouse - Online Learning   There are many kinds of insects.  They may all look    different, but they are alike.  They are alike in three ways. six legs three main body sections (head, thorax, and abdomen) hard skeleton One way all insects are alike is that they have six    legs.  Three legs on each side of the body.  The legs are    attached to the thorax.  The thorax is the middle part of an insect's    body.  Many insects have wings that are attached to the thorax. Behind the thorax is the abdomen.  It is usually    the largest part of an insect. In front of the thorax is the head.  Eyes and a    mouth are located in the head.  Antennae or feelers are also found on    the head.  These are used to smell, feel, and taste things. Insects have a skeleton too!  Their skeleton is on    the outside of their bodies.  It is called an exoskeleton.  Your    skeleton is found inside your body, and it is made of bones.  An    insect's skeleton is the hardest part of its body.  It is made of a    material called chitin. Directions: Answer the questions about insects. How many legs do all insects have? two


What is the name of the structures which allow leaves to breathe?

The Open Door Web Site : Biology : How Plants Breathe : The Differences in the Exchange of Gases between Plant Respiration and Photosynthesis Remember that a green plant respires all the time, day and night. A green plant photosynthesizes only in the presence of sunlight.   All parts of the plant respire, the leaves, the stem, the roots and even the flowers. The parts above the soil get their oxygen directly from the air through pores. The pores in the leaves are called stomata (singular: stoma). The pores in the branches of trees are called lenticels.     The drawing shows a leaf of a ficus plant. A small part of the underside of the leaf has been magnified to show the stomata. The average number of stomata per mm2 of leaf is around 300. The smallest number is found on Tradescantia leaves which have 14 per mm2 . The highest number of stomata is found on the leaves of the Spanish oak tree. Here there are around 1200 per mm2 . The roots of a plant also need oxygen which they obtain from the air spaces in the soil. If you give too much water to a plant in a pot you could kill the roots by drowning them! Plants, such as rice, which normally grow in wet soil often have air spaces in their roots. This is so that they can carry air from the atmosphere down to the root tips to be able to respire under water.   The Open Door Web Site is non-profit making. Your donations help towards the cost of maintaining this free service on-line. Donate to the Open Door Web Site using PayPal © The Open Door Team 2017 Any questions or problems regarding this site should be addressed to the webmaster © Paul Billiet and Shirley Burchill 2017


Which sub-division of plants is named after their practice of forming 'naked seeds'?

plant reproduction Capsule at the top of the sporophyte forms haploid (1n) spores Sexual reproduction in Moss: Moss produce 2 kinds of jacketed gametes --- eggs & sperm Egg producing organ is called the archegonium Eggs are larger and nonmotile Sperm producing organ is called the antheridium Sperm are   smaller, flagellated cells Antheridia & archegonia are both part of the gametophyte plant Fertilization can occur only during or soon after RAIN  when the gametophyte is covered with Water Sperm swim to the egg by following   a trail of chemicals released by the egg in the   water Fertilization produces a zygote that becomes a sporophyte Mature sporophytes produce   homosporous spores (all the same type) Mature   capsules open & release spores spread by wind Spores landing on moist places   germinate into protonema that become new   gametophytes   Small pieces may   break off from a gametophyte & become a new plant (fragmentation) Small buds called gemmae may be washed off by rain and develop new moss plants Fern Characteristics & Life Cycle: Goes through alternation   of generations  Sporophyte phase is the dominant stage Fern   gametophytes are small, flat plants anchored to the soil by root-like   rhizoids Antheridia & archegonia form on the underside of fern gametophytes Sperm swim to egg through water droplets to form zygote   (fertilized egg) Zygotes form new sporophytes with roots, stems, & leaves Spore cases called sori form on the underside of fern fronds (leaves) Ferns are homosporous (single type of spore formed)   New fronds form from an underground stem called the rhizome Vascular   tissue carries   nutrients & water between the parts of the fern Fronds   are compound   leaves attached   by a short stalk called the stipe to the underground stem or rhizome Immature fronds or fiddleheads are coiled   Characteristics & Life Cycle of Conifers: Called gymnosperms Have naked   seeds that   develop on scales of the female   cones Sporophyte is the dominant   stage Adapted   to cooler climates Called evergreens (pine, cedar, spruce, fir...) Giant Redwood is one of the Earth's largest organisms Bristlecone Pines are the oldest living organisms (some more than 5000 years   old) Giant     Redwood The pine   life cycle takes 2-3 years from the   formation of cones until seeds are released Female cones have spirally-arranged scales with ovules at their base Female cones produce sticky resin Ovules contain an egg   that will develop into a seed  Male cones produce large amounts of pollen in the   spring that is spread by wind to the female cones Resin traps the pollen so pollination can occur A tube from the pollen grain takes a year to grow to the ovule so a sperm can fertilize   the egg and form seeds Angiosperms or Flowering Plants: Bright colors,   attractive shapes, and fragrant aromas help flowering plants attract   their pollinators (insects, birds, mammals...) Flowers without   bright colors and pleasing odors are usually wind   or water pollinated (grasses) Called angiosperms Flowers, the   reproductive part of a plant,  have a swollen base or receptacle to attach to the stem Flowers have 4   whorls (modified leaves) attached to the receptacle --- petals,   sepals, pistils, and stamen Pistils (innermost   whorl) are the   female part of the flower, while Stamens are the male part Sepals (outermost   whorl) are found below   the petals and   may look leaf-like (some may be the same color as petals) Sepals enclose the flower bud before it opens  Sepals are collectively called the calyx Petals are often colorful to attract pollinators Petals are collectively called the corolla Monocot flower parts are arranged in multiple of THREES,   while dicots are in multiples of FOUR   or FIVE Perfect   flowers have both stamens & pistils (rose) Imperfect   flowers are either a male (pistillate) or   female (staminate) flower (pumpkin   or melons) Some angiosperms have   both male & female flowers on the SAME plant (monoecious) Othe


What is the state of inactivity through the dry, summer season, as hibernation is the dormancy of the winter months?

Hibernation | Article about hibernation by The Free Dictionary Hibernation | Article about hibernation by The Free Dictionary http://encyclopedia2.thefreedictionary.com/hibernation Also found in: Dictionary , Thesaurus , Medical , Wikipedia . hibernation (hī'bərnā`shən) [Lat.,= wintering], practice, among certain animals, of spending part of the cold season in a more or less dormant state, apparently as protection from cold when normal body temperature cannot be maintained and food is scarce. Hibernating animals are able to store enough food in their bodies to carry them over until food is again obtainable. They do not grow during hibernation, and all body activities are reduced to a minimum: there may be as few as one or two heartbeats a minute. Cold-blooded animals (e.g., insects, reptiles, amphibians, and fish) must hibernate if they live in environments where the temperature—and hence their own body temperature—drops below freezing. Some insects pass their larval stage in a state of hibernation; in such cases hibernation is closely associated with the reproductive cycle (see larva larva, independent, immature animal that undergoes a profound change, or metamorphosis, to assume the typical adult form. Larvae occur in almost all of the animal phyla; because most are tiny or microscopic, they are rarely seen. They play diverse roles in the lives of animals. ..... Click the link for more information. ; pupa pupa , name for the third stage in the life of an insect that undergoes complete metamorphosis, i.e., develops from the egg through the larva and the pupa stages to the adult. ..... Click the link for more information. ). However, most warm-blooded animals, i.e., birds and mammals, can survive freezing environments because their metabolism controls their body temperatures. Many hibernating animals seek insulation from excessive cold; bears and bats retire to caves, and frogs and fish bury themselves in pond bottoms below the frost line. Analogous to hibernation is aestivation, a dormant period of escape from heat and drought. Other methods of avoiding excessively high or low temperatures and destructive increases or decreases in the water supply are encystment and ensuing dormancy, e.g., in plant seeds and bacteria, and migration. Some animals, such as rabbits, raccoons, and squirrels, store food against scarcity and spend cold periods asleep in their burrows, though they may emerge on warm days. Hibernation A term generally applied to a condition of dormancy and torpor found in cold-blooded (poikilotherm) vertebrates and invertebrates. (The term is also applied to relatively few species of mammals and birds, which are warm-blooded vertebrates.) This rather universal phenomenon can be readily seen when body temperatures of poikilotherm animals drop in a parallel relation to ambient environmental temperatures. Poikilotherm animals Hibernation occurs with exposure to low temperatures and, under normal conditions, occurs principally during winter seasons when there are lengthy periods of low environmental temperatures. A related form of dormancy is known as estivation. Many animals estivate when they are exposed to prolonged periods of drought or during hot, dry summers. For all practical purposes, hibernation and estivation in animals are indistinguishable, except for the nature of the stimulus, which is either cold or an arid environment. There is no complete list of animals that hibernate; however, many examples can be found among the poikilotherms, both vertebrate and invertebrate. The poikilotherms are sometimes referred to as ectothermic, because their body temperatures are not internally regulated but follow the rise and fall of environmental temperatures. During hibernation and winter torpor, body temperatures reflect the environmental temperature, often to within a fraction of a degree. Among the classic examples of hibernators or estivators are reptiles, amphibians, and fishes among the vertebrates, and insects, mollusks, and many other invertebrates. For many ectothermic vertebrates (fishes, amphibians, and re


Scorpions, Scorpion Pictures, Scorpion Facts - National Geographic Scientists aren't sure why, but scorpions are fluorescent under ultraviolet light. Size relative to a teacup: Scorpions are members of the class Arachnida and are closely related to spiders, mites, and ticks. They are commonly thought of as desert dwellers, but they also live in Brazilian forests, British Columbia, North Carolina, and even the Himalayas. These hardy, adaptable arthropods have been around for hundreds of millions of years, and they are nothing if not survivors. Survival Adaptations There are almost 2,000 scorpion species, but only 30 or 40 have strong enough poison to kill a person. The many types of venom are effectively tailored to their users' lifestyles, however, and are highly selected for effectiveness against that species' chosen prey. Scorpions typically eat insects, but their diet can be extremely variable—another key to their survival in so many harsh locales. When food is scarce, the scorpion has an amazing ability to slow its metabolism to as little as one-third the typical rate for arthropods. This technique enables some species to use little oxygen and live on as little as a single insect per year. Yet even with lowered metabolism, the scorpion has the ability to spring quickly to the hunt when the opportunity presents itself—a gift that many hibernating species lack. Such survival skills allow scorpions to live in some of the planet's toughest environments. Researchers have even frozen scorpions overnight, only to put them in the sun the next day and watch them thaw out and walk away. But there is one thing scorpions have a difficult time living without—soil. They are burrowing animals, so in areas of permafrost or heavy grasses, where loose soil is not available, scorpions may not be able to survive.


Which part of the common valerian is used to make a sedative?

Valerian — Health Professional Fact Sheet Disclaimer Key points This fact sheet provides an overview of the use of valerian for insomnia and other sleep disorders and contains the following key information: Valerian is an herb sold as a dietary supplement in the United States. Valerian is a common ingredient in products promoted as mild sedatives and sleep aids for nervous tension and insomnia. Evidence from clinical studies of the efficacy of valerian in treating sleep disorders such as insomnia is inconclusive. Constituents of valerian have been shown to have sedative effects in animals, but there is no scientific agreement on valerian's mechanisms of action . Although few adverse events have been reported, long-term safety data are not available. What is valerian? Valerian (Valeriana officinalis), a member of the Valerianaceae family, is a perennial plant native to Europe and Asia and naturalized in North America [ 1 ]. It has a distinctive odor that many find unpleasant [ 2 , 3 ]. Other names include setwall (English), Valerianae radix (Latin), Baldrianwurzel (German), and phu (Greek). The genus Valerian includes over 250 species , but V. officinalis is the species most often used in the United States and Europe and is the only species discussed in this fact sheet [ 3 , 4 ]. What are common valerian preparations? Preparations of valerian marketed as dietary supplements are made from its roots, rhizomes (underground stems), and stolons (horizontal stems). Dried roots are prepared as teas or tinctures , and dried plant materials and extracts are put into capsules or incorporated into tablets [ 5 ]. There is no scientific agreement as to the active constituents of valerian, and its activity may result from interactions among multiple constituents rather than any one compound or class of compounds [ 6 ]. The content of volatile oils , including valerenic acids ; the less volatile sesquiterpenes ; or the valepotriates ( esters of short-chain fatty acids ) is sometimes used to standardize valerian extracts. As with most herbal preparations, many other compounds are also present. Valerian is sometimes combined with other botanicals [ 5 ]. Because this fact sheet focuses on valerian as a single ingredient, only clinical studies evaluating valerian as a single agent are included. What are the historical uses of valerian? Valerian has been used as a medicinal herb since at least the time of ancient Greece and Rome. Its therapeutic uses were described by Hippocrates, and in the 2nd century, Galen prescribed valerian for insomnia [ 5 , 7 ]. In the 16th century, it was used to treat nervousness, trembling, headaches, and heart palpitations [ 8 ]. In the mid-19th century, valerian was considered a stimulant that caused some of the same complaints it is thought to treat and was generally held in low esteem as a medicinal herb [ 2 ]. During World War II, it was used in England to relieve the stress of air raids [ 9 ]. In addition to sleep disorders, valerian has been used for gastrointestinal spasms and distress , epileptic seizures, and attention deficit hyperactivity disorder . However, scientific evidence is not sufficient to support the use of valerian for these conditions [ 10 ]. What clinical studies have been done on valerian and sleep disorders? In a systematic review of the scientific literature , nine randomized , placebo-controlled , double-blind clinical trials of valerian and sleep disorders were identified and evaluated for evidence of efficacy of valerian as a treatment for insomnia [ 11 ]. Reviewers rated the studies with a standard scoring system to quantify the likelihood of bias inherent in the study design [ 12 ]. Although all nine trials had flaws, three earned the highest rating (5 on a scale of 1 to 5) and are described below. Unlike the six lower-rated studies, these three studies described the randomization procedure and blinding method that were used and reported rates of participant withdrawal . The first study used a repeated-measures design; 128 volunteers were given 400 mg of an aqueous extract of valer


What is the name of the structures which allow stems to breathe?


Which acid is contained in rhubarb leaves, making them poisonous to eat?

Are Rhubarb Leaves Poisonous? Make a Natural Insecticide with the Leaves. Many visitors ask, " Can rhubarb leaves be composted?  " It would stand to reason that if the leaves are poisonous, then adding them to compost would be a concern. However, since the oxalic acid is broken down, diluted and pH balanced quite quickly, this is not a concern. Since humans and animals do not normally ingest matter from a compost, rhubarb leaves should be able to be added safely to the compost. Go here for more information and tips for composting rhubarb leaves. Interestingly, the leaves of rhubarb can be used to make a natural insecticide. If you have a large rhubarb patch, you may be interested in making this natural insecticide using the leaves after picking your rhubarb.  A Recipe for Natural Insecticide Using Rhubarb Leaves Boil 500 grams of rhubarb leaves in a few pints of water for about 20 minutes. Allow leaf mixture to cool. Strain the liquid into a CHILD PROOF/SAFE suitable container. Add a tiny bit of dish detergent or soap flakes, (not laundry detergent). Using a spray bottle, spray on leaves to kill off bugs such as aphids and spider mites, June bugs, and fungus diseases. *NOTE - DO NOT spray this product on ANYTHING edible. Rhubarb leaves contain high amounts of oxalic acid, and are poisonous, and could cause death.   If you are interested in more recipes to make simple homemade Natural Pesticides and Insecticides, Go here Here are additional pages within this website that provide helpful information about growing rhubarb in the home garden (or use the website's navigation bars):


What kind of an organism causes a 'rust' attack on plants?

Fungal parasites of plants Home >> Where fungi grow >> Parasites >> Fungal parasites of plants FUNGAL PARASITES OF PLANTS The study of plant disease, plant pathology, is a large and important one. Many universities have entire departments of plant pathology. The importance of the subject is obvious; since the beginning of agriculture humans have had to endure major crop losses because of disease. Even today, when crop health is under careful scrutiny, disease may suddenly strike and ruin an entire season's growth. It happens every year in some part of the globe, even in so-called developed nations. Most plant diseases are caused by fungi; losses to bacteria and viruses are important, but less so than those caused by fungi. A great diversity of fungi cause plant disease, nearly all major groups are involved. In spite of these numbers there are just two types of parasite to consider: nectrotrophs and biotrophs. Necrotrophs are a little like predators; they kill the tissues they are about to consume before they eat them. Unlike predators, however, they don't normally kill the whole organism, just a part of it. They do this by means of toxins that diffuse out into the host tissues, killing the cells they encounter. The fungus then extends its hyphae into these killed areas and digests them. Biotrophs obtain their nutrition from living cells with which they may establish fairly long-lived associations. They usually penetrate the cell walls of their hosts and establish contact with the cell membrane by means of haustoria, cells specialized for the absorption of nutrients. Plants do not just accept parasitic fungi. They have a large array of defense mechanisms that guard against fungal disease so that most fungi cannot get in. These defenses include physical barriers like the tough cuticle lining the surfaces of plants or the bark on trees. Chemical barriers including various toxins and strong oxidizers may be utilized. Fungi in their turn have developed ways of circumventing these defenses and seem to be able to develop new ones as soon as the plant confronts them. Some scientists have referred to this as a biological arms race. Plants differ greatly from one another in how they resist disease. NECROTROPHS The plants in the photo at left are mainly blueberries but if you look closely you will also see chokeberries, raspberries and perhaps some other species. All are common in New Brunswick and are frequently infected by fungi. In this example the leaves are riddled with dead spots brought about by necrotrophic plant parasites. These range from small dark spots to larger dead areas, often ringed by discoloured dying zones. The fungi are within the spots, releasing toxins that kill the leaf cells and then spreading out into the killed areas. Necrotrophic parasites are not always easy to characterize. At times such infections may be caused by biotrophic parasites that make such large nutritional demands on their host that they kill parts of it and thus resemble a necrotroph. However, biotrophs do not produce lethal toxins and they do not feed on dead tissues. BIOTROPHS Because they do not produce toxins biotrophs may have longer and less damaging relationships with their hosts. In the figure at right the rust fungus Chrysomyxa ledi has formed several sites of sporulation on the underside of a leaf of Labrador tea. These areas of sporulation are confined within zones defined by veins. No yellowing or senescence of the host leaf due to this infection is visible although there appears to have been some damage from a necrotroph on the upper margin. DIVERSITY OF PLANT PARASITIC FUNGI Species of fungi causing plant disease can be found in nearly all taxonomic groups and will be encountered frequently in the section on classification . Instead we will examine diversity from a pathologist's point of view, focussing more on the disease than on the agent of the disease. Roots Plant roots are attacked by a great range fungi, from simple organisms parasitic on a single cell to ones attacking an entire root syste


Which is the dominant generation in the ferns?

moss & fern notes b1 The haploid gametophyte stage contains half   the chromosome number & produces gametes   (egg & sperm)  Gametophyte stage is dominant in the moss's life cycle Gametophytes are photosynthetic & have root-like   rhizoids The diploid sporophyte has a complete   set of chromosomes & produces spores by   meiosis Sporophyte of a moss is smaller than, & attached to   the Gametophyte Sporophytes lack chlorophyll & depend on the photosynthetic gametophyte for food Sporophyte has a long, slender stalk topped with a capsule Capsule forms haploid (n) spores  Moss Capsules Sexual Reproduction in Moss: Mosses produce 2 kinds of gametes (egg & sperm) Gametes of   Bryophytes are surrounded by a jacket of sterile cells that keep the cells from drying out Female gametes or eggs are larger with more cytoplasm & are immobile Flagellated sperm must swim to the egg through water droplets for   fertilization Moss gametes form in   separate reproductive structures on the Gametophyte --- Archegonium & Antheridium Archegonium Each Archegonium forms one   egg, but each Antheridium forms many sperm Fertilization can occur only   after rain when the Gametophyte is covered with water Sperms swim to the egg by following a   chemical trail released by the egg  A zygote (fertilized egg) forms that undergoes mitosis and becomes a Sporophyte Cells inside mature Sporophyte capsule undergoes meiosis and form haploid spores Haploid spores germinate into juvenile plants called protonema Protonema begin the   Gametophyte generation Protonema Spores are carried   by wind & sprout on moist soil forming   a new Gametophyte Asexual reproduction in Mosses: Asexual reproduction in moss may occur   by fragmentation or gemmae Pieces of a Gametophyte can break off & form new moss plants (fragmentation) Gemmae are tiny, cup shaped   structures on the Gametophytes  Raindrops separate gemmae from the   parent plant so they can spread & form new Gametophytes  Gemmae cups Serve as pioneer plants on bare rock or ground Help prevent erosion Alternates between dominant   Sporophyte stage & Gametophyte   stage Sporophyte stage has true   roots, stems, & leaves Produce spores on the underside of leaves  Leaves are called fronds & are attached by a   stem-like petiole FERNS Spores produced on underside of fronds in   clusters of sporangia called sori Spores undergo meiosis, are spread by   wind, & germinate on moist soil to form prothallus Prothallus begins the   Gametophyte stage Mature Gametophytes are   small, heart-shaped structures that live only a short time Male antheridia & female archegonia grow on the   prothalli Sperm must swim to the egg to fertilize it & developing embryo becomes the Sporophyte generation Newly forming fronds are   called fiddleheads & uncurl Uses for Ferns:


What is the name of the lustrous substance that forms pearl and mother-of-pearl?

Mother of Pearl Bracelet | zen jewelz zen jewelz – Mother of Pearl Bracelet MOTHER OF PEARL BRACELET: BLISS/ BEAUTY/ COMFORT & MORE! Mother of Pearl  bracelet: Mother of Pearl gets its name from the fact that it is the iridescent lining of shell, where pearls can grow. Shells are related significantly to the ocean, because they have been part of it for many years. The ocean brings feelings of well-being and relaxation, it arouses all of our senses. Wearing Mother of Pearl connects you to beauty, provides comfort, caring, delight, gentleness, love, peacefulness and solace. It is said to attract prosperity. It is used to heighten intuition, psychic sensitivity and imagination. It is said to protect from negative influence and transmute negative energy. Mother of Pearl tends to be highly protective and a particularly potent stone of protection for children. It also is known to purify environments. Mother of Pearl can bring harmony in relationships It can be especially useful for handling and calming emotional situations and be very soothing to the emotions. Wearing Mother of Pearl  healing crystal when working through an emotional situation with someone is said to be beneficial and promotes cooperation. It can assist with the easy flow of feelings and sensitivities to others. It can bring harmony in relationships. It is connected with family, in particular motherhood, which gives it the name “the mothering stone.” zen jewelz – Mother of Pearl Mother of Pearl Bracelet: Physical Healing Properties Mother of Pearl Bracelet: Crystal healing and folklore say that Mother of Pearl is helpful for high blood pressure, dizziness, improving vision, cataracts and wound healing. It can strengthen the immune system, muscle tissues and the heart. It is known to help with arthritis and joint disorders. It can relieve allergies, rashes and skin complaints. What is Mother of Pearl? Mother of pearl, also called  nacre , is an iridescent layer of material that forms the shell lining of many  mollusks . Pearl  oysters  and  abalone  are both sources of this substance, which is widely used as an inlay in jewelry, furniture, and musical instruments. Mother of pearl comes in several natural colors as seen here in cream and white. Mother of Pearl Shell Formation Two substances, one mineral and the other organic, combine to create mother of pearl. Tiny hexagonal plates of aragonite, a form of  calcium carbonate , are arranged in layers alternating with conchiolin, a flexible protein similar to  silk  that is secreted by the mollusk. Aragonite on its own is very brittle, but combined with the protein it forms a strong, flexible material that can withstand hard use. The mollusk first of all secretes a layer of conchiolin. Aragonite crystals then form on this surface at numerous points, growing until they meet each other to form tiny plates. A further layer of protein is then deposited and so on, so that over time, many layers build up. The resilience of pearls comes from its layered structure and the contrast in properties between the mineral and organic layers. The aragonite consists if hard, brittle crystals, while the organic protein layers are a natural  polymer  that is flexible and resistant to fracture. The aragonite gives relative rigidity to the material and the protein counteracts the brittleness of the aragonite by preventing the spread of fractures. The result is a natural product that is tough and resilient.  Mother of pearl has a hardness of about 3.5 on Moh’s scale. This is quite soft compared with gemstones and most metals. Mollusks create Mother of Pearl to protect themselves In addition to forming part of the shell, it also insulates mollusks from bacterial infection and parasites. Another function of this substance is to reduce irritation or damage from material such as sand or grit that drifts into the shell. The particle is gradually surrounded by layers of nacre, rendering it harmless. This may result in a blister-like irregularity on the inside of the shell, or it may create the unattached, spherical structure that is much prize


What is the name of the so-called 'first-bird'?

Archaeopteryx - CreationWiki, the encyclopedia of creation science Archaeopteryx Binomial Name Archaeopteryx lithographica Archaeopteryx is an extinct bird that evolutionists argue possesses some reptilian-like features causing it to be classified as a evolutionary transitional form , and is considered the first of the so called feathered dinosaurs . It has been associated, geologically with the late Jurassic and dated by radiometric dating methods at 150 million years. According to the U.S. National Park Service (Dinosaur National Monument): “ Fossils of Archaeopteryx, a little animal that lived in the middle of dinosaur times, do show traces of feathers, so it has often been called the first bird. But the skeleton of Archaeopteryx looks almost exactly like that of a small meat-eating dinosaur, right down to its tiny sharp teeth. So what was it- -a bird or a dinosaur? Some scientists think that Archaeopteryx was both: a warm-blooded, feathered dinosaur that became the ancestor of the birds. [1] ” 6 See Also Morphology Archaeopteryx was a fully flying and perching bird (though it has an unfused spine, no bill, a reptilian skull, adult teeth, no reptilian snout and bony tail, features seen in no modern bird). Jonathan Sarfati speaks to its bird morphology. “ Archaeopteryx had fully-formed flying feathers (including asymmetric vanes and ventral, reinforcing furrows as in modern flying birds), the classical elliptical wings of modern woodland birds, and a large wishbone for attachment of muscles responsible for the down stroke of the wings. Its brain was essentially that of a flying bird, with a large cerebellum and visual cortex. The fact that it had teeth is irrelevant to its alleged transitional status—a number of extinct birds had teeth, while many reptiles do not. Furthermore, like other birds, both its maxilla (upper jaw) and mandible (lower jaw) moved. In most vertebrates, including reptiles, only the mandible moves. Finally, Archaeopteryx skeletons had pneumatized vertebrae and pelvis. This indicates the presence of both a cervical and abdominal air sac, i.e., at least two of the five sacs present in modern birds. This in turn indicates that the unique avian lung design was already present in what most evolutionists claim is the earliest bird. [2] ” Avian features Feathers are present. No other modern animals except birds have feathers. Archaeopteryx had an opposable hallux (big toe). It is a character of birds and not dinosaurs. A reverse toe is however found in theropod dinosaurs and some other dinosaurs. Furcula (wishbone) formed of two clavicles fused together in the midline. Publis elongate and direct backwards. Bones are pneumatic. Premaxilla and maxilla are not horn-covered (or bills are not present). Trunk region and vertebrae are fused. But in other birds they are always fused. Necks are attached to skull from the rear as in dinosaurs, not from below as in modern birds. Archaeopteryx had a long bony tail. Archaeopteryx had teeth. Nasal opening are far forward and are separated from the eye by a large preorbital fenestra (hole). This is typical of reptiles, but not of birds. Fenestra when present in birds when present is greatly reduced, and is involved in prokinesis (movement of the beak). Recent discoveries seem to have shown that there are enough similarities between Archaeopteryx and Dromaeosaur that they can be considered varieties of the same created kind . This includes evidence from Dromaeosaur's feathers that it could fly. Archaeopteryx is dated as 20 million years older than Dromaeosaur. Archaeopteryx could not have evolved from Dromaeosaur. In fact Archaeopteryx is older than most of its alleged ancestors, which is a BIG problem for evolutionists, assuming total and complete replacement (thus extinction) of the original species . [Reference needed] News


What is the Latin word for 'liquid' which we use to mean the fluid produced by the tree Ficus elastica?

Tapping Trees for Natural Rubber - How Rubber Works | HowStuffWorks Tapping Trees for Natural Rubber Bryn Campbell/ Getty Images The Mesoamerican peoples, such as the Mayans and the Aztecs , first tapped rubber from one of several trees found in Central and South America: Hevea braziliensis: the most common commercial rubber tree from Brazil Hevea guyanensis: originally found in French Guyana Castilla elastica: sometimes called the Mexican rubber tree or the Panama rubber tree Explorers and colonists brought samples of these trees when they headed back to Europe . Eventually, seeds from these trees were transported to rubber plantations in other tropical climates during the era of European colonialism. Up Next Currently, most natural rubber comes from Latin American-derived trees transplanted to Southeast Asia ( Thailand , Indonesia , Malaysia ), as well as India , Sri Lanka and Africa . In these areas, you can find other rubber-producing trees including: Ficus elastica: found in Java and Malaysia. This species is also a common tropical houseplant. Funtumia elastica: grows in West Africa Landolphia owariensis located in the Congo basin Of all of these trees, the best rubber-producing tree is H. braziliensis. It takes about six years for a rubber tree to grow to a point where it's economical to harvest the sap, which is called latex. Here's how you tap one: The collector makes a thin, diagonal cut to remove a sliver of bark. The milky-white latex fluid runs out of the bark, much as blood would run out of a small superficial wound on your skin. The fluid runs down the cut and is collected in a bucket. After about six hours, the fluid stops flowing. In that six-hour period, a tree can usually fill a gallon bucket. The tree can be tapped again with another fresh cut, usually the next day. The Mesoamericans would dry the collected rubber latex and make balls and other things, like shoes. They would dip their feet in the latex and allow it to dry. After several dips and dryings, they could peel a shoe from their feet. Next, they smoked their new rubber shoes to harden them. The Mesoamericans also waterproofed fabrics by coating them with latex and allowing it to dry. This process was used to make rubber items until around the 1800s. Columbus brought back rubber balls with him upon returning from his second voyage to the New World, and in the early 1700s, rubber samples and trees were brought back to Europe. At that time, rubber was still a novelty. Rubber made in the Mesoamerican way resembled a pencil eraser. It was soft and pliable. In 1770, the chemist Joseph Priestley was the first to use rubber to erase lead marks. He coined the word "rubber" because he could remove the lead marks by rubbing the material on them. While it was useful for waterproofing fabrics and making homemade shoes, rubber had its problems. You can see these problems for yourself with a simple rubber pencil eraser. Take that eraser and place it under intense heat for several minutes. What do you see? The eraser should get very soft and sticky. Next, do the opposite -- place the eraser on ice or in a freezer for several minutes. What do you see? The eraser should get hard and brittle. The same thing happened to early rubber. Imagine what it would be like to walk around in your rubber shoes on a hot or cold day back then. The shoes wouldn't wear well. Likewise, your rubberized clothing might stick to your chair while you were sitting, especially on a warm day. Keep reading to learn what makes rubber so intrinsically stretchy.


What is the main use of the tree Citrus bergamia?

Bergamot oil (Citrus bergamia) - information on the origin, source, extraction method, chemical composition, therapeutic properties and uses. Go to shopping cart at bottom of page This fresh smelling essential oil is a favorite in aromatherapy and is great for creating a more relaxed and happy feeling, relieving urinary tract infections, boosting the liver, spleen and stomach, while fighting oily skin, acne, psoriasis, eczema, as well as cold sores. Oil properties The scent of the oil is basically citrus, yet fruity and sweet, with a warm spicy floral quality and is reminiscent of neroli as well as lavender oil. The color ranges from green to greenish-yellow and the oil has a watery viscosity. Origin of bergamot oil This tree is native to South East Asia, but was introduced to Europe, and particularly Italy and is also found in the Ivory Coast, Morocco, Tunisia and Algeria. Bergamot oil is made from a tree that can grow up to four meters high, with star-shaped flowers and smooth leaves, bearing citrus fruit resembling a cross between an orange and a grapefruit, but in a pear-shape. The fruit ripens from green to yellow. The oil is one of the most widely used in the perfumery and toiletry industry and forms, together with neroli and lavender, the main ingredient for the classical 4711 Eau-de-cologne fragrance. It is used to flavor Earl Grey tea. The name is derived from the city Bergamo in Lombardy, Italy, where the oil was first sold. Summary When you are looking for an oil to help with depression, SAD (Seasonal Affected Disorder) or generally feeling just a bit off, lacking in self-confidence or feeling shy, then consider bergamot oil. It also has superb antiseptic qualities that are useful for skin complaints, such as acne, oily skin conditions, eczema and psoriasis and can also be used on cold sores, chicken pox and wounds. It has a powerful effect on stimulating the liver, stomach and spleen and has a superb antiseptic effect on urinary tract infections and inflammations such as cystitis. Burners and vaporizers In vapor therapy, bergamot oil can be used for depression, feeling fed-up, respiratory problems, colds and flu, PMS and SAD. Blended massage oil or in the bath It can be used in a blended massage oil, or diluted in a bath to assist with stress, tension, SAD, PMS, skin problems, compulsive eating, postnatal depression, colds and flu, anxiety, depression, feeling fed-up and anorexia nervosa. Blended in base cream As a constituent in a blended base cream bergamot oil can be used for wounds and cuts, psoriasis, oily skin, scabies, eczema, acne, cold sores as well as chicken pox. Bergamot blends well with Although essential oils blend well with one another, bergamot oil goes particularly well with other essential oils such as black pepper , clary sage , cypress , frankincense , geranium , jasmine , mandarin , nutmeg , orange , rosemary , sandalwood , vetiver and ylang-ylang .   US$ 14.50 for 10 ml ( worldwide postage included ) To shop, click on the "Add to shopping cart" button above, which will add the item to your cart, where we accept Visa, MasterCard, Amex and Diners credit cards. After you have selected an item, other items can also be added to the cart. All products are accessible from the product catalogue , or from the list below. When you are ready to finalize your order, click the "Go to checkout now" button where you will be able to change quantities, delete items, or return if you decide to continue shopping. Remember - no order is final until you decide and place the order. For more information on shopping cart security, please click here . To access our fax form click here . Handling, shipping and postage to any destination in the world INCLUDED (EXCEPT SOUTH AFRICA) - this is the total price - there are no hidden extras.


Which physician developed a type of remedy involving wild flowers?

Dr Bach's system of 38 flower remedies Contact us if you have a specific question and can't find an answer on the site. Guide to the remedies Each of the 38 remedies discovered by Dr Bach is directed at a particular characteristic or emotional state. To select the remedies you need, think about the sort of person you are and the way you are feeling. For more information on each remedy in this list click the relevant link. It might help to read some case studies first to see how they work. Agrimony - mental torture behind a cheerful face Aspen - fear of unknown things


The best longbows were constructed from which wood?

Bow woods Bow building for poor people and apartment dwellers Brought to you by: SAM HARPER Home | Update Archives | Other bow building sites | Thanks to all who helped me | Gallery | Youtube Channel Bow woods There are bow woods I've tried and bow woods I haven't tried. This is a list of bow woods (and grass in the case of bamboo) I've tried or heard a lot about. I'm only considering limb wood material, not handle wood material. Don't limit yourself, though. People are trying new things all the time. Red oak The great thing about red oak is that it's easy to find and it's cheap. It's ideal for somebody who is just starting out. Just about every Home Depot or Lowes I've been to has it. They sell it in the perfect size, too. It comes in a 72" long board they call a 1x2, which is actually 3/4 x 1-1/2. Red oak is very porous, and most of the pores are in the early growth rings, so it's important to find a piece with thick late growth rings or else it will seem brittle. Those boards will feel heavier. If you find a board with very straight grain, you don't necessarily need to back it, but it's a good idea to back any board bow. Bamboo The wonderful thing about bamboo is that you're guaranteed to have straight grain. Bamboo bows rarely fail if done right. Some people call bamboo nature's fiberglass. It's great bow material, and it's cheap. Bamboo comes in different forms�raw bamboo and bamboo flooring boards. If you get the flooring boards, be sure to get vertical grain. The horizontal grain will come apart. Bamboo flooring makes a great bow if backed with raw bamboo. All bamboo bows are my personal favourite. They're quieter than any other bow I've made, and there's just something about the way they feel when you draw them and shoot them that's hard to describe. There's a smoothness about them. The only bad thing I have to say about bamboo bows is that they take a lot of set. It's a good idea to put a lot of reflex in the bow at glue-up if you want to have any left after tillering. Vertical grain flooring boards can also be cut into laminations. People sometimes refer to it as "action boo." It's ideal in the core of a fiberglass bow, because it's light and strong. Raw bamboo is just a slice of a solid piece of bamboo with the nodes still intact. It makes a great backing to almost any kind of bow. Bamboo is very strong in tinsel strength, so it needs to be very thin to avoid overpowering the belly wood. Some woods that are good with raw bamboo backing include osage, yew, ipe, and bamboo, because they can withstand the compression forces. Hickory Hickory is popular for backing bows. Like bamboo, it's very strong in tinsel strength, so it needs to be thin. It's not quite as strong in compression strength. It makes a good self bow, too. I haven't made a self bow out of it, but from what I've read, it's almost impossible to break. Some people question its durability, though. Apparently, it takes a lot of set over time and becomes sluggish. I think this may be due to the fact that hickory sucks up a lot of moisture from the atmosphere. It needs to be a tad dryer than other woods to get the best performance out of it. The only problem with using it to make a self bow is that it's almost impossible to get the bark off of it. I've heard several different methods, the most popular being to put it in a hot shower for 20 or 30 minutes before trying to get the bark off with a chisel. Osage Some people consider osage (bois d'ark) to be a weed, but to those of us who make bows, it's gold. I love everything about osage except for the fact that it's hard to find a straight piece of it without knots. It smells good, it looks good, and it's the ideal bow wood. It lasts forever without taking a set, and it's very strong in compression strength. I can't say enough about osage. I just love it. If only it were easier to come by! Ipe It's pronounced EE-pay. It's the same thing as Brazilian walnut. It's very strong, so you can make thinner and lighter limbs, resulting in a faster bow. It goes well with a bamboo backing. Ipe is used in decks, because


How many species of domestic dog are found today?

Domestic Dogs, Domestic Dog Pictures, Domestic Dog Facts - National Geographic Size relative to a 6-ft (2-m) man Please add a "relative" entry to your dictionary. Dogs were probably the first tame animals. They have accompanied humans for some 10,000 years. Some scientists assert that all dogs, domestic and wild, share a common ancestor in the small South Asian wolf. Today humans have bred hundreds of different domestic dog breeds—some of which could never survive in the wild. Despite their many shapes and sizes all domestic dogs, from Newfoundlands to pugs, are members of the same species—Canis familiaris. Although they have domestic temperaments, these dogs are related to wolves, foxes, and jackals. Domestic dogs still share many behaviors with their wild relatives. Both defend their territories and mark them by urinating on trees, rocks, fence posts, and other suitable sites. These scent posts serve notice to other dogs that an animal is occupying its territory. Many pet dogs also bury bones or favorite toys for future use, just as their wild relatives sometimes bury a kill to secure the meat for later feasts. Dogs communicate in several ways. Scent is one method, another is physical appearance. Body position, movement, and facial expression often convey a strong message. Many of these signals are recognizable even to humans, such as the excited tail-wagging of a happy dog or the bared teeth of an angry or threatened animal. Vocally, dogs communicate with a cacophony of sounds including barks, growls, and whines. Domestic dogs serve as more than companions; many earn their keep by working hard. Dogs herd livestock, aid hunters, guard homes, and perform police and rescue work. Some special animals even guide the blind—a poignant symbol of the dog's longstanding role as man's best friend.


Barnacle (Cirripedia) - Animals - A-Z Animals Characteristics unique to the animal Latch on to hard surfaces and shell made up from plates Barnacle Location Barnacle The barnacle is a hardy animal that is found in or very closely to sea water. Although it is frequently confused for a mollusc because of its hard outer shell, it is actually a crustacean, closely related to crabs and lobsters. Barnacles are most often seen as roughly circular sessile invertebrates (which means that they cannot move on their own), and are permanently attached to the substrate they live on. In their juvenile form they are free-floating, but eventually they attach themselves to any nearby rock, shell, or other object and stay there for the rest of their lives. Their shells are composed of calcite. Barnacles are often seen on crabs , whales, boats, rocks and on the shells of sea turtles . Although some species of barnacle are parasitic, most barnacle species are harmless, because they are filter feeders and do not interfere with an animal's normal diet and do not harm that animal that they live on in any way. Many species of barnacle are so harmless that in fact, an animal that is covered in them, may not even notice! There are more than 1,000 known species of barnacle that inhabit shallow and tidal waters around the world. Although many species of barnacle are very small, some can grow to as large as 7cm and even bigger barnacles can often be seen. Barnacles typically live for between 5 and 10 years, but some of the larger species are known to be much older. Barnacles attach themselves to animals when they are very young and in the larvae stage of their lives. Once the baby barnacle has effectively glued itself to something hard, a thin layer of flesh wraps around the barnacle and an outer shell is produced. Once the barnacle has an outer shell, it is protected from the elements and all kinds of predators . As soon as the baby barnacle has fixed itself onto something, it is generally there for the rest of it's life. Barnacles are filter feeders (also known as suspension feeders) that feed on food particles that they strain out of the water. The shell of the barnacle is made up of a number of plates (usually 6), with feathery leg-like appendages that draw water into their shell so that they can feed. Barnacles have numerous predators , particularly when they are babies and floating around in the water looking for something to attach themselves to. As the barnacle larvae are so tiny, they float around with the plankton in the water. Once the barnacle is older and has it's tough outer shell, few predators can actually eat it. Humans are known to eat goose barnacles (the only edible species of barnacle) in parts of Europe like Spain and Portugal. Most species of barnacles are hermaphroditic which means that they have both male and female reproductive organs . Although it is possible for barnacles to self-fertilise their eggs, it seems to be very rare so the eggs produced by one barnacle are usually fertilised by another barnacle . It takes more than 6 months for the barnacle larvae to start developing into the hardier adult barnacles. Barnacles are thought to be one of the oldest surviving creatures on the planet as they are believed to date back millions of years. Although there will have been some adaptations, the barnacle is thought to have changed very little over that time. Despite the rising levels of pollution and changes in the water, barnacles are thought to be one of the few animals that are not greatly affected. The barnacle slides two of it's six plates across to let water in when it is feeding and then closes them again which prevents the barnacle from being too exposed to dirty water. Share This Article


Machiavelli used which plant's name as the title of one of his books?

Machiavelli, Comedian | The Public Domain Review ..or BROWSE BY TAG Machiavelli, Comedian Most familiar today as the godfather of Realpolitik and as the eponym for all things cunning and devious, the Renaissance thinker Niccolò Machiavelli also had a lighter side, writing as he did a number of comedies. Christopher S. Celenza looks at perhaps the best known of these plays, Mandragola, and explores what it can teach us about the man and his world. Illustration of Machiavelli featured in the title page to Historie di Nicolo Machiavegli cittadino & secretario fiorentino (1540) – Source . “Comedian”, admittedly, isn’t the first word you associate with Machiavelli. And “funny” is not a word normally applied to Lucretius. And yet, through some strange alchemy of time, circumstance, and the rhythms of Renaissance life, those seemingly discordant elements came together in a remarkable way. You could argue that Machiavelli’s entire worldview was comic, but comic in a peculiar way: ironic, wry, a little melancholy, punctuated by an earthy vulgarity that, these days, would get him thrown off a university faculty in a minute. More than this, the central premises of what was funny have changed so significantly that it invites us to think about how comedy works and when it’s time to say that a comedy, however venerable, just isn’t funny anymore. Take his play, Mandragola, or, in English, “The Mandrake Root.” The odd title (and it would have been odd in Machiavelli’s day, too) has to do with fertility. The plant appears in the Bible, in contexts where carnal knowledge is in question, like when Leah, one of Jacob’s two wives, wants to convince him to lie with her (Gen. 30:14-16), or when, in the Song of Songs, a woman sings a song of her own seductiveness “I am my beloved’s, and his desire is toward me … The mandrakes give a smell, and at our gates are all manner of pleasant fruits ….” (Song of Songs, 7:10-13). If the lasting biblical associations of the plant had to do with love, the herb also had magical and spell-like connotations. It could be thought to induce a great and powerful sleep, and in some accounts was even thought to cry out when pulled from the earth. Image from Ibn Butlan’s 14th-century Tacuinum sanitatis in Medicina, portraying a favoured medieval method – using a dog and string – for safely extracting a mandrake without enduring its shrieks – Source . Machiavelli’s title enfolded many of these meanings. The play concerns a young man, Callimaco, who though Florentine in origin spent much of his youth in France. From clues in the play we learn he is about thirty years old and that the action is set in the year 1504. At a gathering of friends, all male of course, a debate breaks out over who has the more beautiful women, France or Italy. Though the debaters give the palm to French women, one of his Florentine friends says he has a relative, Lucrezia, whose beauty is unequalled anywhere. Callimaco becomes curious to the point of leaving France and going to Florence. There his curiosity escalates to passion, as he is all but driven mad by love after finally laying eyes on Lucrezia. As it happens Lucrezia is married to a slow-witted lawyer named Messer Nicia. They have been trying unsuccessfully to have children. Ligurio – a matchmaker and, not coincidentally, a friend of Callimaco – suggests that the couple’s troubles may allow Callimaco to get close to Lucrezia. At first, Ligurio suggests that the couple go to the baths, known to improve fertility. Callimaco says he will go, so that he can see Lucrezia and because di cosa nasce cosa – “one thing begets another”. He is ready to trust his instincts and improvise as need be to find a way to be with Lucrezia. But then another plan is hatched. This one involves an elaborate scheme whereby Callimaco, posing as a doctor, convinces dull-witted Nicia to have Lucrezia take a special potion to help her conceive. The catch? The first person to make love with Lucrezia after she takes this potion will die. But thereafter, she will be fertile, children will follow, and all will be well,


What is the name of the evolutionary theory suggesting that evolution has an uneven pace?

Modern Theory of Evolution For those that love God's creation Modern Theory of Evolution There is a modern theory of evolution. There are some things we have learned over the last 150 years since Charles Darwin first proposed his theory of "descent with modification." Darwin's theory was amazingly accurate considering the state of scientific knowledge in 1859. Darwin knew nothing of DNA or genes, backbones of the modern theory of evolution. He even leaned toward Lamarckism, the belief that traits developed during our lifetime would pass on to our children. Nonetheless, The basics of Darwin's theory of evolution were exactly right and have passed every test with flying colors for 150 years: My pages are prone to being a little long. I can't do you good service and make this page shorter. A fast reader can read this page in under 3 minutes. If you want to skim it, I have highlighted portions that will allow you to get the gist of the page. Nature's imperfect reproductive methods regularly produce mutations, so that there are always unique individuals. Individuals which, as a result of those mutations, are better adapted to their environment will have more offspring, either because they survive more often or are better able to attract mates. Those more suitable adaptations will be prone to spreading through an entire population. Over time, as those adaptations accumulate, populations are modified into new species. Given the immense amount of geologic time on this earth, this process, known as "natural selection," has produced all life on the earth from one or a few parents. This basic idea of descent with modification has been backed up on every front. Here, however, are some of the new things that we've learned over the last 150 years. DNA: The Book of Life The modern theory of evolution is able to speak much more clearly about how evolution happens due to the discovery of DNA, the genetic code that controls all natural life. Charles Darwin was able to say: Therefore I should infer from analogy that probably all the organic beings which have ever lived on this earth have descended from some one primordial form, into which life was first breathed. (On the Origin of Species, ch. 14) Darwin had to base that on the following similarities between all living things: Common chemical composition Common germinal vesicle (this is a nucleus that is formed when a cell begins to split in two) Common cellular structure Common laws of growth and reproduction As an example of these commonalities, he cited a common reaction to poisons, so that a gall-fly's secretions creates the same growth on a wild rose as it does on an oak tree (ibid.). From the modern theory of evolution we know that the similarities are far more than he could have imagined. Every living cell has a common code, the simple 4-letter code of DNA, that controls its growth and reproduction. Every human, every insect, every plant, and every bacteria consists of cells made of proteins that are coded for by DNA. All DNA is transferable. Some viruses, which are not even cells but mere snippets of DNA, have even been assimilated into human DNA during our evolutionary history (see Wikipedia, "Human Endogenous Retrovirus" ). Even more interestingly, today insulin for diabetics is produced by taking human DNA and putting it in bacteria or yeast cells so that they produce the exact insulin that our bodies produce. Here's how the International Diabetes Foundation describes it: Rather than being extracted from human pancreases, commercially available human insulin is manufactured through recombinant DNA technology, in which the gene for making human insulin is transferred into simple cells such as bacteria or bakerís yeast. The insulin made by those cells is identical to insulin made by the human pancreas. (From www.idf.org ) Whether you object to evolution or not, you have to admit that this method of insulin production is amazing. The modern theory of evolution takes into account the genetic code, which Darwin could have known nothing about. Punctuated Equilibrium We'll cover punctu


Which step in photosynthesis is responsible for splitting water molecules?

Chemistry for Biologists: Photosynthesis Leaves and leaf    structure | The structure of the chloroplast    and photosynthetic membranes | Stages of    photosynthesis | Non-cyclic phosphorylation    (the Z scheme) | Chemiosmosis and ATP    synthesis | Cyclic phosphorylation | The light-independent reactions | Summary of stages of photosynthesis | Factors affecting the rate of photosynthesis | Test your knowledge Photosynthesis Photosynthesis is the process by which plants, some    bacteria and some protistans use the energy from sunlight to produce glucose    from carbon dioxide and water. This glucose can be converted into pyruvate    which releases adenosine triphosphate (ATP) by cellular respiration. Oxygen is    also formed. Photosynthesis may be summarised by the word equation: carbon dioxide +     water glucose + oxygen The conversion of usable sunlight energy into chemical energy    is associated with the action of the green pigment chlorophyll. Chlorophyll is a complex molecule. Several modifications of    chlorophyll occur among plants and other photosynthetic organisms. All    photosynthetic organisms have chlorophyll a. Accessory pigments absorb energy    that chlorophyll a does not absorb. Accessory pigments include chlorophyll b    (also c, d, and e in algae and protistans), xanthophylls, and carotenoids (such    as beta-carotene). Chlorophyll a absorbs its energy from the violet-blue and    reddish orange-red wavelengths, and little from the intermediate    (green-yellow-orange) wavelengths. Chlorophyll - click on image to open All chlorophylls have: a lipid-soluble hydrocarbon tail    (C20H39 -) a flat hydrophilic head with a magnesium ion at its centre;    different chlorophylls have different side-groups on the head The tail and head are linked by an ester bond. Leaves and leaf structure Plants are the only photosynthetic organisms to have leaves    (and not all plants have leaves). A leaf may be viewed as a solar collector    crammed full of photosynthetic cells. The raw materials of photosynthesis, water and carbon dioxide,    enter the cells of the leaf, and the products of photosynthesis, sugar and    oxygen, leave the leaf. Water enters the root and is transported up to the leaves    through specialized plant cells known as xylem vessels. Land plants must guard    against drying out and so have evolved specialized structures known as stomata to allow gas to enter and leave the leaf. Carbon dioxide cannot    pass through the protective waxy layer covering the leaf (cuticle), but    it can enter the leaf through the stoma (the singular of stomata),    flanked by two guard cells. Likewise, oxygen produced during photosynthesis can    only pass out of the leaf through the opened stomata. Unfortunately for the    plant, while these gases are moving between the inside and outside of the leaf,    a great deal of water is also lost. Cottonwood trees, for example, will lose    100 gallons (about 450 dm3) of water per hour during hot desert    days. The structure of the chloroplast and    photosynthetic membranes The thylakoid is the structural unit of photosynthesis. Both    photosynthetic prokaryotes and eukaryotes have these flattened sacs/vesicles    containing photosynthetic chemicals. Only eukaryotes have chloroplasts with a    surrounding membrane. Thylakoids are stacked like pancakes in stacks known    collectively as grana. The areas between grana are referred to as stroma. While    the mitochondrion has two membrane systems, the chloroplast has three, forming    three compartments. Structure of a chloroplast Stages of photosynthesis When chlorophyll a absorbs light energy, an electron gains    energy and is 'excited'. The excited electron is transferred to another    molecule (called a primary electron acceptor). The chlorophyll molecule is    oxidized (loss of electron) and has a positive charge. Photoactivation of    chlorophyll a results in the splitting of water


Which kind of organisms are likely to show a 'taxis'?

HOW AND WHY WE CLASSIFY LIVING ORGANISMS Content Updated: 20th July 2008 Generally-speaking, we humans have a desire to label and categorize  things – hands up those who keep their t-shirts in a separate drawer to  their underwear and/or arrange them in order of most recently worn or  colour. Coupled with our desire for order (some teenagers excluded!), is  an equally strong desire to name things we’ve sorted. The great Chinese  thinker and philosopher K'ung Fu Tzu (better known by his Latin name:  Confucius) is widely credited as being the source of the old Chinese  proverb: “The beginning of wisdom is to call things by their right  name.” But, what’s the point of naming things? Why go to the hassle of  trying to give every novel object its own name? We name objects because it makes our life easier. Let’s say you’re  sitting on the sofa and you want your friend to pass the remote so you  can see what else is on the TV – this process is rather difficult  without names. A request like, “Please pass the thing on the thingy. I  want to see what’s on the whats-am-a-jig”, is likely to meet with  confusion. The request is easier for the other person to follow if  things have names: “Please pass the remote on the coffee table. I want  to see what’s on the TV”. Now, it’s true that you might be able to  gesticulate at your friend until he or she either gets the idea, or  misinterprets and takes offence, but what if you can’t see the person  you need help from – charades doesn’t help then. Imagine that you’re  sitting on the train going to work when you remember you forgot to get  the pie out of the freezer to defrost in time for dinner; fortunately  your partner has the day off and is at home. So, you phone up and ask  “Can you get the thing out of the thingy so it’s thingy-ed in time for what’s-its-name?” Again, confusion reigns. Gesticulating won’t help  because the other person can’t see you (although it might make a dull  train ride more interesting for your fellow passengers!). The  instructions can be followed when we insert the names: “Can you get the pie out of the freezer so that it’s defrosted in time for dinner?” So, the act of naming is a matter of convenience – whether the  objects are pieces or furniture, bits of machinery, or animals we assign  them names because it makes life a heck of a lot easier for us. We, for  example, call a ‘fish’ with a cartilaginous skeleton and between five  and seven pairs of gills a “shark”. This allows us to tell another  person what animal we’re looking at or talking about. The use of a name  certainly helps, but not without problems. Telling someone that you went  diving with sharks while on holiday is kinda like saying you went out  for dinner with some primates; it’s not quite as specific as we might  want because there are lots of different ‘types’ of primates (and  sharks). Consequently, to make our meaning as clear as possible, objects  (be they animals, plants, bacteria, furniture, tools, etc.) are split  into as narrow groups as possible and each group is given a name. So, for example, the group of ‘fish’ we call sharks gets further  split up into different types of sharks based largely on how they look  (their “morphology”), both internally (i.e. their skeleton, internal  organs etc.) and externally (i.e. fins, gills, skin, colour etc.). Large  groups are then split into smaller (i.e. more specific) ones and so on  down the line until you have a group containing all the animals  considered to be exactly the same in terms of the features we’re looking  at (these can be morphological, genetic, ecological, biochemical, even  behavioural): this is the species level (we’ll look at this in more  detail later). Humans, chimpanzees, great white sharks, blackbirds,  palmate newts and red squirrels are all examples of species. Some  taxonomists opt to take the splitting below the species level and group  animals into subspecies, infraspecies and forms (among others). Perhaps  the extr


Which part of the brain regulates physiological stability in the body?

Human Physiology/Homeostasis - Wikibooks, open books for an open world Human Physiology/Homeostasis This is the latest reviewed version , checked on 21 December 2016. (+)  Quality: minimal   Overview[ edit ] The human organism consists of trillions of cells all working together for the maintenance of the entire organism. While cells may perform very different functions, all the cells are quite similar in their metabolic requirements. Maintaining a constant internal environment with all that the cells need to survive (oxygen, glucose, mineral ions, waste removal, and so forth) is necessary for the well-being of individual cells and the well-being of the entire body. The varied processes by which the body regulates its internal environment are collectively referred to as homeostasis. What is Homeostasis?[ edit ] Homeostasis in a general sense refers to stability or balance in a system. It is the body's attempt to maintain a constant internal environment. Maintaining a stable internal environment requires constant monitoring and adjustments as conditions change. This adjusting of physiological systems within the body is called homeostatic regulation. Homeostatic regulation involves three parts or mechanisms: 1) the receptor, 2) the control center and 3) the effector. The receptor receives information that something in the environment is changing. The control center or integration center receives and processes information from the receptor. And lastly, the effector responds to the commands of the control center by either opposing or enhancing the stimulus. This is an ongoing process that continually works to restore and maintain homeostasis. For example, in regulating body temperature there are temperature receptors in the skin, which communicate information to the brain, which is the control center, and the effector is our blood vessels and sweat glands in our skin. Because the internal and external environments of the body are constantly changing and adjustments must be made continuously to stay at or near the set point, homeostasis can be thought of as a synthetic equilibrium. Since homeostasis is an attempt to maintain the internal conditions of an environment by limiting fluctuations, it must involve a series of negative feedback loops. Positive and Negative Feedback[ edit ] When a change of variable occurs, there are two main types of feedback to which the system reacts: Negative feedback: a reaction in which the system responds in such a way as to reverse the direction of change. Since this tends to keep things constant, it allows the maintenance of homeostasis. For instance, when the concentration of carbon dioxide in the human body increases, the lungs are signaled to increase their activity and expel more carbon dioxide. Thermoregulation is another example of negative feedback. When body temperature rises, receptors in the skin and the hypothalamus sense a change, triggering a command from the brain. This command, in turn, effects the correct response, in this case a decrease in body temperature. Home Heating System Vs. Negative Feedback When you are at home, you set your thermostat to a desired temperature. Let's say today you set it at 70 degrees. The thermometer in the thermostat waits to sense a temperature change either too high above or too far below the 70 degree set point. When this change happens the thermometer will send a message to to the "Control Center", or thermostat,which in turn will then send a message to the furnace to either shut off if the temperature is too high or kick back on if the temperature is too low. In the home-heating example the air temperature is the "NEGATIVE FEEDBACK." When the Control Center receives negative feedback it triggers a chain reaction in order to maintain room temperature. Positive feedback: a response is to amplify the change in the variable. This has a destabilizing effect, so does not result in homeostasis. Positive feedback is less common in naturally occurring systems than negative feedback, but it has its applications. For example, in nerves, a threshold electr


Which organ is responsible for regulating the blood sugar level?

Insulin Regulation of Blood Sugar and Diabetes - The Important Roles of Insulin and Glucagon: Diabetes and Hypoglycemia Normal Regulation of Blood Glucose The Important Roles of Insulin and Glucagon: Diabetes and Hypoglycemia Written by James Norman MD, FACS, FACE The human body wants blood glucose (blood sugar) maintained in a very narrow range. Insulin and glucagon are the hormones which make this happen. Both insulin and glucagon are secreted from the pancreas, and thus are referred to as pancreatic endocrine hormones. The picture on the left shows the intimate relationship both insulin and glucagon have to each other. Note that the pancreas serves as the central player in this scheme.  It is the production of insulin and glucagon by the pancreas which ultimately determines if a patient has diabetes, hypoglycemia, or some other sugar problem. In this Article Insulin's Role in Blood Glucose Control Insulin Basics: How Insulin Helps Control Blood Glucose Levels Insulin and glucagon are hormones secreted by islet cells within the pancreas. They are both secreted in response to blood sugar levels, but in opposite fashion! Insulin is normally secreted by the beta cells (a type of islet cell) of the pancreas. The stimulus for insulin secretion is a HIGH blood glucose...it's as simple as that!  Although there is always a low level of insulin secreted by the pancreas, the amount secreted into the blood increases as the blood glucose rises. Similarly, as blood glucose falls, the amount of insulin secreted by the pancreatic islets goes down.  As can be seen in the picture, insulin has an effect on a number of cells, including muscle, red blood cells, and fat cells.  In response to insulin, these cells absorb glucose out of the blood, having the net effect of lowering the high blood glucose levels into the normal range. Glucagon is secreted by the alpha cells of the pancreatic islets in much the same manner as insulin...except in the opposite direction. If blood glucose is high, then no glucagon is secreted.  When blood glucose goes LOW, however, (such as between meals, and during exercise) more and more glucagon is secreted. Like insulin, glucagon has an effect on many cells of the body, but most notably the liver. The Role of Glucagon in Blood Glucose Control The effect of glucagon is to make the liver release the glucose it has stored in its cells into the bloodstream, with the net effect of increasing blood glucose. Glucagon also induces the liver (and some other cells such as muscle) to make glucose out of building blocks obtained from other nutrients found in the body (eg, protein). Our bodies desire blood glucose to be maintained between 70 mg/dl and 110 mg/dl (mg/dl means milligrams of glucose in 100 milliliters of blood). Below 70 is termed "hypoglycemia." Above 110 can be normal if you have eaten within 2 to 3 hours.  That is why your doctor wants to measure your blood glucose while you are fasting...it should be between 70 and 110.  Even after you have eaten, however, your glucose should be below 180. Above 180 is termed "hyperglycemia" (which translates to mean "too much glucose in the blood"). If your 2 two blood sugar measurements above 200 after drinking a sugar-water drink (glucose tolerance test), then you are diagnosed with diabetes.   Updated on: 03/02/16


What is the scientific name for the human ''tail'?

The science of human tails The science of human tails Go to permalink Some hold with the theory that the development of an embryo shows the stages of evolution. In other words, what first develops is fishlike, and then like a small mammal, and then like a lemur or ape, and then something we would recognize as human. Very early embryos have what look like little gill slits in the beginning of their development. At about four weeks, embryos have a little tail. At around six to twelve weeks, the white blood cells dissolve the tail, and the fetus develops into an average, tail-less baby... most of the time, at least. Every now and again, we get a little extra bit of baby, in the form of a vestigial tail. Advertisement Not all things that look like tails - protrusions from the tailbone - actually are what doctors consider "true" tails. There are a number of growths or cysts that can form right on the tip of the tailbone. Some of the more unpleasant options are large tumors, elongation of the existing vertebrae, and even parasitic twin tissue. (A parasitic twin is not a fully-formed twin, but the product of another fertilized egg that somehow became fused with the embryo and never developed into a full human being.) True tails form when the white blood cells, for whatever reason, don't absorb all the tissue that formed during embryonic development. These babies carry the marks of humans earliest ancestors. Because there are only between 20 and 30 cases of "true" vestigial tails since the late 1800s, there is some controversy about what such a tail contains. Some early accounts say that there are sometimes extra vertebrae in such tails. No modern tails have been found to have any bone tissue. They're mostly skin with fat, connective tissue, nerves, and muscle tissue. They can be just a stub, but some babies can be born with tails 13 centimeters long. The tails aren't strictly useless inert structures. Because they have muscle tissue inside, they can actually be twitched back and forth, or even contracted into curves. These days babies don't have their tails long enough to gain a lot of muscle control over them. Removing them is a simple operation, usually done not long after birth. Advertisement What remains are questions of why these tails grow in the first place. They're rare enough that researchers aren't left with many clues. Researchers have, for the most part, ruled out family history - which throws the science of the X-Files episode I got the top image from right out the window. The tails are associated with spina bifida, a dangerous condition in which the canals of the spinal cord don't entire close before birth, but they are often present without the disorder. And for some reason they're twice in common in males as they are in females. In the end, no one knows why some babies just develop tails. (Besides, gills are much more practical.)


When might a person show rapid eye movement (REM)?

Understanding Dreams and REM Sleep Understanding Dreams and REM Sleep Search the site Updated August 02, 2016 What are Dreams? Dreams happen during the rapid eye movement (REM) stage of sleep . In a typical night, you dream for a total of 2 hours, broken up by the sleep cycle . Researchers do not know much about how we dream or why. They do know that newborns dream and that depriving rats of REM sleep greatly shortens their lives. Other mammals and birds also have REM sleep stages, but cold-blooded animals such as turtles, lizards and fish do not. REM Sleep and Dreaming REM sleep usually begins after a period of deep sleep known as stage 4 sleep. An area of the brain called the pons--where REM sleep signals originate--shuts off signals to the spinal cord . That causes the body to be immobile during REM sleep. When the pons doesn't shut down the spinal cord's signals, people will act out their dreams. This can be dangerous because acting out dreams without input from the senses can lead a person to run into walls, fall down stairs or worse. This condition is rare and different from more common sleepwalking and known as “REM sleep behavior disorder.” The pons also sends signals to cerebral cortex by way of the thalamus (which is a filter and relay for sensory information and motor control functions deep in the brain). The cerebral cortex is the part of the brain involved with processing information (learning, thinking and organizing). The areas of the brain “turned on” during REM sleep seem to help learning and memory. Infants spend almost 50 percent of their sleep time in REM sleep (compared to 20 percent for adults), which may be explained by the tremendous amount of learning in infancy. If people are taught various skills and then deprived of REM sleep, they often cannot remember what they were taught. The Meaning of Dreams Dreams may be one way that the brain consolidates memories. The dream time could be a period when the brain can reorganize and review the day’s events and connect new experiences to older ones. Because the body is shut down, the brain can do this without additional input coming in or risking the body “acting out” the day’s memories. Some researchers believe that dreams are more like a background “noise” that is interpreted and organized. This theory states that dreams are merely the brain’s attempt to make sense of random signals occurring during sleep. Some people have more control over their dreams than others. For these people, the last thoughts before going to bed may influence the content of a dream. Of course, psychologists and most people look for greater meaning and insight in dreams. Here are some common dreams with interpretations: Falling: Dreams of falling are said to indicate insecurity. Freud thought dreams of falling meant the contemplation of giving into a sexual urge. Flying: Dreams of flying are said to indicate feeling in control or 'on top of' a situation. The Naked Dream: Dreams of being naked are said to indicate that you are ashamed of something or have something to hide. Personally, these interpretations feel a bit too pop psych to me. I think by engaging with your dreams and thinking about them you can determine what meaning might be conveyed for your life. (I keep having a dream about forgetting to wear socks, please leave comments if you have any insight). You can develop your ability to remember your dreams by keeping a journal near your bed and writing down everything you can about your dreams when you first wake up. After a few weeks, your ability to remember your dreams will improve. Some people claim that they have lucid dreams, which are dreams in which they can participate and change the dream as it develops. Lucid dreaming can be triggered through a number of techniques, though little research and lots of speculation has been done on it.


Which organ removes excess water from the blood?

Which organ removes excess water, salts, uric acids, and chemicals from the blood?  the kidneys, the lungs, the sweat glands, or the pharynx ? You have new items in your feed. Click to view. Question and answer Which organ removes excess water, salts, uric acids, and chemicals from the blood?  the kidneys, the lungs, the sweat glands, or the pharynx ? The organ that is responsible for all of these removals is the kidney Expert answered| Ashnicole49 |Points 70| Which organ removes excess water, salts, uric acids, and chemicals from the blood? the kidneys, the lungs, the sweat glands, or the pharynx ? New answers There are no new answers. Comments Log in or sign up first. Questions asked by the same visitor Weegy: The correct answer is decreases. (More) Question Asked 12/3/2012 8:20:08 PM 0 Answers/Comments Weegy: Distribution systems: allocate endless goods and services. (More) Question Asked 12/3/2012 8:22:56 PM 0 Answers/Comments Why is the majority of Earth's freshwater not readily available for our use?  It is in the atmosphere. ? It is locked up in glaciers and ice caps. ? It is in rivers far from major human population centers. ? or It is in the ground. ? Weegy: The answer to your questions , The majority of Earth's freshwater not readily available for our use because out of all the water on Earth, only 2.75 percent is freshwater, which includes 2.05 percent frozen in glaciers. [ This leaves a very small amount of non salt water. Most is locked up in glaciers and icecaps in Greenland and Antarctica, in saline inland seas or in the atmosphere, and is not readily available for consumptive use. ] (More) Question Asked 12/3/2012 8:29:42 PM 0 Answers/Comments Weegy: Surface processes that work to break down rock are called weathering. (More) Question Asked 12/3/2012 8:58:25 PM 0 Answers/Comments On a global basis, which of the following is the largest reservoir of carbon? ANS: atmosphere. The important reservoirs are: Atmosphere: contains at present 750 GtC. In pre-industrial times it contained only about 570 GtC, this change corresponds to the variation in the abundance from 280 ppmv in pre-industrial times to 370 ppmv at present. Vegetation and soils in the land: these contain about 2200 GtC, in the form of all the mass of plants in the Earth and all the organic litter contained in the soil, which has a lot of carbon. surface ocean: contains 1000 GtC. Carbon dioxide is dissolved in the water. Most of the live organisms that carry out photosynthesis in the ocean are near the surface, they can absorb the dissolved carbon dioxide and release it when they die. The surface ocean can rapidly exchange carbon dioxide with the atmosphere. deep ocean: contains 39000 GtC. This contains much more carbon than all the reservoirs above, but it can only exchange carbon with the atmosphere very slowly. lithosphere and mantle: contains about one hundred million GtC. This is by far the largest reservoir. The carbon dioxide is stored in the interior of the Earth in the form of carbonate rocks, such as limestone, dolomites, and chalk. However, carbon from this reservoir is exchanged extremely slowly with the carbon in the ocean and atmosphere. Among this large reservoir there are also about 4000 GtC in the form of fossil fuels (oil, coal and natural gas). These fossil fuels have been buried for hundreds of millions of years and are now being extracted and burned by humans. Added 12/3/2012 9:28:23 PM


Which is the most acidic part of the digestive system?

Digestive System: Facts, Function & Diseases Digestive System: Facts, Function & Diseases By Kim Ann Zimmermann, Live Science Contributor | March 11, 2016 05:15pm ET MORE The human digestive system is a series of organs that converts food into essential nutrients that are absorbed into the body and eliminates unused waste material. It is essential to good health because if the digestive system shuts down, the body cannot be nourished or rid itself of waste. Description of the digestive system Also known as the gastrointestinal (GI) tract, the digestive system begins at the mouth, includes the esophagus, stomach, small intestine, large intestine (also known as the colon) and rectum, and ends at the anus. The entire system — from mouth to anus — is about 30 feet (9 meters) long, according to the  American Society of Gastrointestinal Endoscopy  (ASGE).  Digestion begins with the mouth. Even the smell of food can generate saliva, which is secreted by the salivary glands in the mouth, contains an enzyme, salivary amylase, which breaks down starch. Teeth, which are part of the skeletal system, play a key role in digestion. In carnivores, teeth are designed for killing and breaking down meat. Herbivores’ teeth are made for grinding plants and other food to ease them through the digestion process.  [ Image Gallery: The BioDigital Human ] Swallowing pushes chewed food into the esophagus, where it passes through the oropharynx and hypopharynx. At this point, food takes the form of a small round mass and digestion becomes involuntary. A series of muscular contractions, called peristalsis, transports food through the rest of the system. The esophagus empties into the stomach, according to the  National Institutes of Health  (NIH).  The stomach’s gastric juice, which is primarily a mix of hydrochloric acid and pepsin, starts breaking down proteins and killing potentially harmful bacteria, according to ASGE. After an hour or two of this process, a thick semi-liquid paste, called chyme, forms. At this point the pyloric sphincter valve opens and chyme enters the duodenum, where it mixes with digestive enzymes from the pancreas and acidic bile from the gall bladder, according to the  Cleveland Clinic . The next stop for the chyme is the small intestine, a 20-foot (6-meter) tube-shaped organ, where the majority of the absorption of nutrients occurs. The nutrients move into the bloodstream and are transported to the liver.  The liver creates glycogen from sugars and carbohydrates to give the body energy and converts dietary proteins into new proteins needed by the blood system. The liver also breaks down unwanted chemicals, such as alcohol, which is detoxified and passed from the body as waste, the Cleveland Clinic noted. Whatever material is left goes into the large intestine. The function of the large intestine, which is about 5 feet long (1.5 meters), is primarily for storage and fermentation of indigestible matter. Also called the colon, it has four parts: the ascending colon, the transverse colon, the descending colon and the sigmoid colon. This is where water from the chyme is absorbed back into the body and feces are formed primarily from water (75 percent), dietary fiber and other waste products, according to the Cleveland Clinic. Feces are stored here until they are eliminated from the body through defecation. Diseases of the digestive system Many symptoms can signal problems with the GI tract, including: abdominal pain, blood in the stool, bloating, constipation, diarrhea, heartburn, incontinence, nausea and vomiting and difficulty swallowing, according to the NIH. Among the most widely known diseases of the digestive system is  colon cancer . According to the Centers for Disease Control (CDC), 51,783 Americans died from colon cancer in 2011 (the most recent year for available data). Excluding skin cancers, colon and rectal cancer, or colorectal cancer, is the third most common cancer diagnosed in both men and women in the United States, according to the  American Cancer Society . Polyp growth and irregular cells, which may or ma


A deficiency of which vitamin can cause scurvy?

Scurvy: Causes, Symptoms and Treatments - Medical News Today Scurvy: Causes, Symptoms and Treatments Written by Peter Crosta M.A. 4 36 Scurvy is a disease caused by a diet that lacks vitamin C (ascorbic acid). Patients develop anemia , debility, exhaustion, edema (swelling) in some parts of the body, and sometimes ulceration of the gums and loss of teeth. The name scurvy comes from the Latin scorbutus. We have known about the disease in humans since ancient Greek and Egyptian times. Scurvy commonly is associated with sailors in the 16th to 18th centuries who navigated long voyages without enough vitamin C and frequently perished from the condition. Modern cases of scurvy are extremely rare. Humans cannot synthesize vitamin C, which is necessary for the production of collagen and iron absorption. We have to obtain it from external sources, i.e. from fruits and vegetables, or some foods which are fortified with vitamin C in order to prevent the vitamin C deficiency known as scurvy. Vitamin C deficiency is especially dangerous for the fetus (developing baby in the womb). Researchers from the University of Copenhagen reported in the journal PLOS ONE that pregnant women with a vitamin C deficiency can have babies whose brain did not develop properly . What causes scurvy? The primary cause of scurvy is insufficient intake of vitamin C (ascorbic acid). This may be due to ignorance, famine, anorexia , restrictive diets (due to allergies, food fads, etc.), or difficulty orally ingesting foods. Historically, scurvy was the result of long sea voyages where sailors did not bring along enough foods with vitamin C. Who gets scurvy? Though scurvy is a very rare disease, it still occurs in some patients - usually elderly people, alcoholics, or those that live on a diet devoid of fresh fruits and vegetables. Similarly, infants or children who are on special or poor diets for any number of economic or social reasons may be prone to scurvy. Symptoms of scurvy Scurvy symptoms may begin with appetite loss, poor weight gain, diarrhea , rapid breathing, fever , irritability, tenderness and discomfort in legs, swelling over long bones, bleeding (hemorrhaging), and feelings of paralysis. As the disease progresses, a scurvy victim may present bleeding of the gums, loosened teeth, petechial hemorrhage of the skin and mucous membranes (a tiny pinpoint red mark), bleeding in the eye, proptopsis of the eyeball (protruding eye), constochondral beading (beading of the cartilage between joints), hyperkeratosis (a skin disorder), corkscrew hair, and sicca syndrome (an automimmune disease affecting connective tissue). Infants with scurvy will become apprehensive, anxious, and progressively irritable. They often will assume the frog leg posture for comfort when struck with pseudoparalysis. It is common for infants with scurvy to present subperiosteal hemorrhage, a specific bleeding that occurs at the lower ends of the long bones. Diagnosis of scurvy Physicians initially will conduct a physical exam, looking for symptoms described above. Actual vitamin C levels can be obtained by using laboratory tests that analyze serum ascorbic acid levels (or white blood cell ascorbic acid concentration). Sometimes, radiological procedures are ordered for diagnostic purposes and to see what damage scurvy has already done. Treatments for scurvy Scurvy is treated by providing the patient with vitamin C, administered either orally or via injection. Orange juice usually functions as an effective dietary remedy, but specific vitamin supplements are also known to be effective. How can scurvy be prevented? Scurvy can be prevented by consuming enough vitamin C, either in the diet or as a supplement. Foods that contain vitamin C include: Oranges, lemons, kiwi fruit and strawberries are all excellent natural sources of vitamin C. Oranges