bee |
chisel |
top 10 words in brain distribution (in article): species plant fruit food seed produce bird flower male female |
top 10 words in brain distribution (in article): light produce type color form design allow contain time common |
top 10 words in brain distribution (not in article): animal grow tree leaf breed sugar hunt fish cat water |
top 10 words in brain distribution (not in article): drink lamp cell wine beer water bottle key lock body |
times more probable under bee 30 20 10 6 4 2.5 1.25 1 1.25 2.5 4 6 10 20 30 times more probable under chisel (words not in the model) | |
Bees'" are flying insects closely related to wasps and ants. Bees are a monophyletic lineage within the superfamily "'Apoidea'", presently classified by the unranked taxon name "'Anthophila'". There are nearly 20,000 known species of bee, in nine recognized families, though many are undescribed and the actual number is probably higher. They are found on every continent except Antarctica, in every habitat on the planet that contains insect-pollinated flowering plants. Introduction. Bees are adapted for feeding on nectar and pollen, the former primarily as an energy source, and the latter primarily for protein and other nutrients. Most pollen is used as food for larvae. Bees have a long proboscis (a complex "tongue") that enables them to obtain the nectar from flowers. They have antennae almost universally made up of 13 segments in males and 12 in females, as is typical for the superfamily. Bees all have two pairs of wings, the hind pair being the smaller of the two; in a very few species, one sex or caste has relatively short wings that make flight difficult or impossible, but none is wingless. The smallest bee is "Trigona minima", a stingless bee whose workers are about 2.1 mm (5 64") long. The largest bee in the world is "Megachile pluto", a leafcutter bee whose females can attain a length of 39 mm (1.5"). Members of the family Halictidae, or sweat bees, are the most common type of bee in the Northern Hemisphere, though they are small and often mistaken for wasps or flies. The best-known bee species is the European honey bee, which, as its name suggests, produces honey, as do a few other types of bee. Human management of this species is known as beekeeping or apiculture. Bees are the favorite meal of "Merops apiaster", the bee-eater bird. Other common predators are kingbirds, mockingbirds, bee wolves, and dragonflies. Pollination. Bees play an important role in pollinating flowering plants, and are the major type of pollinator in ecosystems that contain flowering plants. Bees either focus on gathering nectar or on gathering pollen depending on demand, especially in social species. Bees gathering nectar may accomplish pollination, but bees that are deliberately gathering pollen are more efficient pollinators. It is estimated that one third of the human food supply depends on insect pollination, most of which is accomplished by bees, especially the domesticated European honey bee. Contract pollination has overtaken the role of honey production for beekeepers in many countries. Monoculture and the massive decline of many bee species (both wild and domesticated) have increasingly caused honey bee keepers to become migratory so that bees can be concentrated in seasonally-varying high-demand areas of pollination. Most bees are fuzzy and carry an electrostatic charge, which aids in the adherence of pollen. Female bees periodically stop foraging and groom themselves to pack the pollen into the scopa, which is on the legs in most bees, and on the ventral abdomen on others, and modified into specialized pollen baskets on the legs of honey bees and their relatives. Many bees are opportunistic foragers, and will gather pollen from a variety of plants, while others are oligolectic, gathering pollen from only one or a few types of plant. A small number of plants produce nutritious floral oils rather than pollen, which are gathered and used by oligolectic bees. One small subgroup of stingless bees, called "vulture bees," is specialized to feed on carrion, and these are the only bees that do not use plant products as food. Pollen and nectar are usually combined together to form a "provision mass", which is often soupy, but can be firm. It is formed into various shapes (typically spheroid), and stored in a small chamber (a "cell"), with the egg deposited on the mass. The cell is typically sealed after the egg is laid, and the adult and larva never interact directly (a system called "mass provisioning"). Visiting flowers can be a dangerous occupation. Many assassin bugs and crab spiders hide in flowers to capture unwary bees. Other bees are lost to birds in flight. Insecticides used on blooming plants kill many bees, both by direct poisoning and by contamination of their food supply. A honey bee queen may lay 2000 eggs per day during spring buildup, but she also must lay 1000 to 1500 eggs per day during the foraging season, mostly to replace daily casualties, most of which are workers dying of old age. Among solitary and primitively social bees, however, lifetime reproduction is among the lowest of all insects, as it is common for females of such species to produce fewer than 25 offspring. The population value of bees depends partly on the individual efficiency of the bees, but also on the population itself. Thus, while bumblebees have been found to be about ten times more efficient pollinators on cucurbits, the total efficiency of a colony of honey bees is much greater, due to greater numbers. Likewise, during early spring orchard blossoms, bumblebee populations are limited to only a few queens, and thus are not significant pollinators of early fruit. Depopulation. Recently, managed populations of European honey bees have experienced substantial declines. This has prompted investigations into the phenomenon amidst great concern over the nature and extent of the losses. One aspect of the problem is believed to be "Colony Collapse Disorder" but many of the losses outside the US are attributed to other causes. Pesticides used to treat seeds, such as Clothianidin and Imidacloprid, may also negatively impact honey bee populations. Other species of bees such as mason bees are increasingly cultured and used to meet the agricultural pollination need. Most native pollinators are solitary bees, which often survive in refuge in wild areas away from agricultural spraying, but may still be poisoned in massive spray programs for mosquitoes, gypsy moths, or other insect pests. Evolution. Bees, like ants, are a specialized form of wasp. The ancestors of bees were wasps in the family Crabronidae, and therefore predators of other insects. The switch from insect prey to pollen may have resulted from the consumption of prey insects that were flower visitors and were partially covered with pollen when they were fed to the wasp larvae. This same evolutionary scenario has also occurred within the vespoid wasps, where the group known as "pollen wasps" also evolved from predatory ancestors. Up until recently the oldest non-compression bee fossil had been "Cretotrigona prisca" in New Jersey amber and of Cretaceous age, a meliponine. A recently reported bee fossil, of the genus "Melittosphex", is considered "an extinct lineage of pollen-collecting Apoidea sister to the modern bees", and dates from the early Cretaceous (~100 mya). Derived features of its morphology ("apomorphies") place it clearly within the bees, but it retains two unmodified ancestral traits ("plesiomorphies") of the legs (two mid-tibial spurs, and a slender hind basitarsus), indicative of its transitional status. The earliest animal-pollinated flowers were pollinated by insects such as beetles, so the syndrome of insect pollination was well established before bees first appeared. The novelty is that bees are "specialized" as pollination agents, with behavioral and physical modifications that specifically enhance pollination, and are generally more efficient at the task than beetles, flies, butterflies, pollen wasps, or any other pollinating insect. The appearance of such floral specialists is believed to have driven the adaptive radiation of the angiosperms, and, in turn, the bees themselves. Among living bee groups, the Dasypodaidae are now considered to be the most "primitive", and sister taxon to the remainder of the bees, contrary to earlier hypotheses that the "short-tongued" bee family Colletidae was the basal group of bees; the short, wasp-like mouthparts of colletids are the result of convergent evolution, rather than indicative of a plesiomorphic condition. Eusocial and semisocial bees. Bees may be solitary or may live in various types of communities. The most advanced of these are eusocial colonies found among the honey bees, bumblebees, and stingless bees. Sociality, of several different types, is believed to have evolved separately many times within the bees. In some species, groups of cohabiting females may be sisters, and if there is a division of labor within the group, then they are considered semisocial. If, in addition to a division of labor, the group consists of a mother and her daughters, then the group is called eusocial. The mother is considered the "queen" and the daughters are "workers". These castes may be purely behavioral alternatives, in which case the system is considered "primitively eusocial" (similar to many paper wasps), and if the castes are morphologically discrete, then the system is "highly eusocial". There are many more species of primitively eusocial bees than highly eusocial bees, but they have rarely been studied. The biology | A chisel'" is a tool with a characteristically shaped cutting edge (such that wood chisels have lent part of their name to a particular grind) of blade on its end, for carving or cutting a hard material such as wood, stone, or metal. The handle and blade of some types of chisel are made of metal or wood with a sharp edge in it. In use, the chisel is forced into the material to cut the material. The driving force may be manually applied or applied using a mallet or hammer. In industrial use, a hydraulic ram or falling weight ('trip hammer') drives the chisel into the material to be cut. A "gouge", one type of chisel, is used, particularly in woodworking, woodturning and sculpture, to carve small pieces from the material. Gouges are most often used in creating concave surfaces. A gouge typically has a 'U'-shaped cross-section. Types of Chisels. Chisels have a wide variety of uses. Many types of chisels have been devised, each specially suited to its intended use. Different types of chisels may be constructed quite differently, in terms of blade width or length, as well as shape and hardness of blade. They may have wooden handles attached or may be made entirely of one piece of metal. Woodworking chisels. Woodworking chisels range from quite small hand tools for tiny details, to large chisels used remove big sections of wood, in 'roughing out' the shape of a pattern or design. Typically, in woodcarving, one starts with a larger tool, and gradually progresses to smaller tools to finish the detail. One of the largest types of chisel is the slick, used in timber frame construction and wooden shipbuilding. According to their function there are many names given to woodworking chisels, such as: Japanese woodworking chisels. The better quality Japanese wood chisels are made from laminated steel. There are different types of metals used in each chisel. The better ones are laminated by hand, over a charcoal fire. The combination of the metals makes a chisel that takes a very sharp edge, and is hard enough to maintain the edge for a long time. This technique produces a tools that have a harder edge, usually a hardness rating of Rockwell 64, compared to their western counterparts of around 62 on the Rockwell scale. There are two basic metals used in these chisels, white steel and blue steel. The names come from the color of the paper the steels are wrapped in. White and blue steel come in vary grades, that vary in carbon content. Both have low levels of impurities. White steel is a simple carbon steel. Blue steel contains alloying elements, and sacrifices some sharpness for edge retention, toughness, and corrosion resistance, although it is not stainless. Many makers are descendants of the samurai sword makers, once highly respected members of their country, until these swords were outlawed. The chisel makers often turned their attention to chisel and plane makers. Expensive sets have a decorative wood grain look to them which is actually the thin layers of steel being hammered together. The neck of the chisel can be twisted to add to the decorative look of the tool. The handles are often made from an exotic hardwood, such as ebony. The sets usually come in a wooden box, signed by the maker. Japanese chisels have hollows in the back side, the wider ones having as many as four hollows. These are intended to help in the flattening of the back of the chisels, which is the first step in sharpening a chisel. Once the back side is perfectly flat, and polished to the required degree, the front and side edges need to be addressed. A general rule is any chisel with a hoop, or metal ring at the end of the handle, is it's designed to be struck with mallet. If it does not have a hoop, it is a paring tool, designed not to be struck with another tool. Lathe tools. A lathe tool is a woodworking chisel designed to cut wood as it is spun on a lathe. These tools have longer handles for more leverage, needed to counteract the tendency of the tool to react to the downward force of the spinning wood being cut or carved. In addition, the angle and method of sharpening is different, a secondary bevel would not be ground on the tool. Woodworking chisels range from quite small hand tools for tiny details, to large chisels used remove big sections of wood, in 'roughing out' the shape of a pattern or design. Typically, in woodcarving, one starts with a larger tool, and gradually progresses to smaller tools to finish the detail. One of the largest types of chisel is the slick, used in timber frame construction and wooden shipbuilding. Metalworking chisels. Chisels used in metal work can be divided into two main categories, "hot" chisels, and "cold" chisels. A hot chisel is used to cut metal that has been heated in a forge to soften the metal. Cold chisel. A cold chisel'" is a tool made of tempered steel used for cutting 'cold' metals, meaning that they are not used in conjunction with heating torches, forges, etc. Cold chisels are used to remove waste metal when a very smooth finish is not required or when the work cannot be done easily with other tools, such as a hacksaw, file, bench shears or power tools. The name cold chisel comes from its use by blacksmiths to cut metal while it was cold as compared to other tools they used to cut hot metal. This tool is also commonly referred to by the misnomer 'coal chisel'. Because cold chisels are used to form metal, they have a less-acute angle to the sharp portion of the blade than a woodworking chisel. This gives the cutting edge greater strength at the expense of sharpness. Cold chisels come in a variety of sizes, from fine engraving tools that are tapped with very light hammers, to massive tools that are driven with sledgehammers. Cold chisels are forged to shape and hardened and tempered (to a brown colour) at the cutting edge. The head of the chisel is chamfered to slow down the formation of the mushroom shape caused by hammering and is left soft to withstand hammer blows. The are four common types of cold chisel. These are the flat chisel, the most widely known type, which is used to cut bars and rods to reduce surfaces and to cut sheet metal which is too thick or difficult to cut with snips. The cross cut chisel is used for cutting grooves and slots. The blade narrows behind the cutting edge to provide clearance. The round nose chisel is used for cutting semi-circular grooves for oil ways in bearings. The diamond point chisel is used for cleaning out corners or difficult places and pulling over centre punch marks wrongly placed for drilling. Although the vast majority of cold chisels are made of steel, a few are manufactured from beryllium copper, for use in special situations where non-sparking tools are required. Hardy chisel. A toothed stone chisel, used by stone sculptors and stonemasons A "'hardy chisel'" is a type of hot chisel with a square shank, which is held in place with the cutting edge facing upwards by placing it in an anvil's Hardy hole. The hot workpiece cut is then placed over the hardy, and struck with a hammer. The hammer drives the chisel into the hot metal, allowing it to be snapped off with a pair of tongs. Stone chisels. Stone chisels are used to carve or cut stone, bricks or concrete slabs. To cut, as opposed to carve, a brick bolster is used; this has a wide, flat blade that is tapped along the cut line to produce a groove, then hit hard in the centre to crack the stone. Sculptors use a "spoon chisel", which is bent, with the bezel (cutting edge) on both sides. To increase the force, stone chisels are often hit with club hammers, a heavier type of hammer. Masonry chisels. Masonry chisels are typically heavy, with a relatively dull head that wedges and breaks, rather than cuts. Normally used as a demolition tool, they may be mounted on a hammer drill, jack hammer, or hammered manually, usually with a heavy hammer of three pounds or more. Plugging chisel. A Plugging chisel has a tapered edge for cleaning out hardened mortar. The chisel is held with one hand and struck with a hammer. The direction of the taper in the blade determines if the chisel cuts deep or runs shallow along the joint. |