How exactly does a body know what type of food is eaten when determining evolutionary tooth development?
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A group of animals is living in an area - foodsource = nuts. The ones with good crushing teeth will eat lots, reproduce and pass on the crushing design gene. Any with ripping design etc would be unsuccessful in gaining food and thus wouldn't reproduce and pass on the ripping gene. Eventually all members of the species have crushing teeth. Survival of the fittest etc. A lion with blunt teeth would not live long enough to pass on the genes
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Ben T needs to go back to class.\n\nAutotrophs make their own food from energy and simple chemicals in the environment, like plants and blue-green algae (anything with chlorophyll, although there is some chemosynthetic life that eats sulphur and stuff around hydrothermal vents!)\n\nHeterotrophs eat other living things or previously living things. I am a heterotroph because I had scrambled eggs and bananas for breakfast. Fungi are heterotrophs because they eat decomposing logs and leaves on forest floors, among other things.
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"Variation in Diet\nAlthough helodermatid lizards are specialists on vertebrate nests, they appear to be generalists regarding the kinds of nests they exploit.\nA diversity of prey species and sizes has been documented in the diets of Beaded Lizards and Gila Monsters.  Although some of these prey items are relatively small lizard and snake eggs, others, such as quail nets and nestling rabbits, are large and provice substantial energy gains per food item.  A meal of cottontail nestlings can weigh over one-third the mass of an adult Gila Monster and provide nearly one-third of a Gila Monster's annual energy budget (Beck 1990; chap. 4).  Along with these energy benefits come the basic mechanical challenges of swallowing a large meal or a hard-shelled egg.  Egg-eating snakes of the genera Dasypeltis and Elachistodon have modifications of the jaws, teeth, skull, and even the vertebrae that allow them to efficiently swallow eggs (Gans 1974). Although helodermatid lizards are not so specialized, they do appear to use a few "tricks" to make eggs go down easier.\n\nFeeding Behavior\nHow Prey are Eaten\nHerrel et al. (1997) describe five stages of H. horridum eating quail eggs: approach, pierce, uptake, crush, and swallow.  A Beaded Lizard first locates the egg, both visually and by tongue-flicking, then rises on its front legs and bites the egg with its front teeth, piercing it without breaking it.  The piercing bite may be repeated several times, yet the egg remains intact.  During the uptake phase, the lizard maneuvers its jaws around the egg by either flicking the egg in the air or pushing it against an object or the ground.  The tongue aids in maneuvering the food object into the oral cavity, but the primary force used during the uptake phase is inertia generated by movements of the lizard's head, neck, and jaws.  Such a feeding mechanism, called inertial feeding, contrasts with lingual feeding mechanisms (using the tongue to deliver food objects into the mouth) shown by most other lizards (Gans 1969)..."\n\nNot information about the actual digestive system, but information about diet and feeding.  This is an excerpt from Daniel D. Beck's new book.\n\nLet me know if you want a photo of a Gila Monster!
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twice because the sugars in the food that you eat attaches itself your teeth and bacteria grows. This bacteria breaks down the enamel of you teeth causing cavities.
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Every fossil, every observation in biology points to evolution. There is nothing that goes against it or points to a different way to scientifically explain modern diversity. There is not one fossil or one piece of DNA that does NOT point to evolution.\nCreation relies on a lot of belief and the ability to dismiss all the known evidence, since ancient Greece to the present time, in the case for evolution.\nEvolution, on the other hand, keeps presenting solid evidence, regardless of those who believe otherwise. \n\nHere is a theoretical example of natural selection and adaptation.\n\nSay you have an island, about twenty miles from any other island, where there is a species of bird, say finches. In any population of birds, there is going to be a variety of beak sizes and wing sizes, (like nose and ear size, and height variation in humans), suddenly there was a drought, lasting several years, and the main food source of the finches, say, sesame seed, was destroyed, and all they had to eat was wheat, which is harder to break and eat than sesame. \nWhat characteristics would give one bird an advantage over another? Those with smaller beaks would have more difficulty cracking the wheat and feeding it to any baby birds, therefore they would have less live young. Those with largeer, stronger beaks would crack and eat more wheat and have more live young. Chances are, that their offspring would have, on average, larger, stronger beaks than those of small beaked finches. The stronger your beak, the more you eat, the more children you have. \nSo what other characteristics? Those with stronger, larger wings could try to find other food, but if they can't make to the other island, they die, those that make it to the other island, and if it has food, will have, on average, larger wings than those that didn't make it. They wil have more children, who, on average, will have larger wings.\nThese are simplified examples, it is more complex than this, but the basics are there.\n\nAnother, real life example is the Peppered moth.\nHere is the Wikipedia link\nhttp://en.wikipedia.org/wiki/Peppered_moth_evolution\n\nThis is evolution at work.\nRead more about evolution, but do it with an open mind. It wiil be of no use looking at evidence if you have already decided to reject it. Remember, you are doing science, at that is what scientist do. The more you read, the more you will understand. Try "Origin of Species " by Charles Darwin as a start, or try Google for a summary.\n\nGood luck to you.
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The coelom is the true body cavity, coelomates are characterized by having a body cavity lined with mesoderm.  \n\nSharks (Chondrichthyes) are coelomates.
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.  Animals which have a simple evolutionary history are usually soft bodied, and soft bodies animal do not leave good fossils.  It is easy to find analogs for evolutionary steps toward certain animals, the whale for example,  but finding an clear-cut sequence of fossils is difficult.\n.  But, looking at analogs, consider the weasel, the otter, the seal, the manatee and the whale.  The difference between any two steps in this sequence is fairly small, but the difference from one end to the other seems quite large.\n.  There are enough fossils whose ages may be determined that, studied as a group, studied as a group, they demonstrate an increase in complexity of organisms over time and indicate familial relationships.  Bony headed fishes, known only from fossils, were the ancestors of fish like the coelacanth.  Fishes like the collegian were ancestral to both modern fishes and the fish which pulled themselves up from the water on strong, bony fins.\n.  The horse has some obvious ancestors, but the the fossil record of those ancestor becomes weaker as you go back in time.  The fossil record  between shrew like mammals and those creatures which had some horse like characteristics has big gaps in it..
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Turtles have no teeth, and they grab their food using their horny "beaks", which have sharp edges. The inner part of the jaws is more plate-like and can crush harder materials, but they usually swallow large chunks.\nIn contrast to lizards, turtles have a well developed secondary palate (similar to ours), so they can use their flat tongue to push food against the palate, before swallowing it.\nUnlike most sea turtles, the green sea turtles (Chelonia mydas) are herbivorous, and they feed mostly on algae and other sea plants, which are not hard.\nPictures of sea turtle skull:\nhttp://www.umanitoba.ca/faculties/science/zoology/faculty/horn/z232/labs/bones/seaturt.jpg\nNotice the flat premaxilla, maxilla, and dentary bones, and the palatines forming the hard palate.\n\nThe digestive system of turtles comprises a single stomach, intestines and finally a cloaca.
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In human enamel trace elements of Fe, Zn, Sr, Cu, Mn and Ag are found. The concentration of some of these elements varies with distance from the surface of the tooth. For example, Fe and Zn (and also Pb and Sn which are present in lower concentration in enamel) accumulate near the surface of the tooth, ie in the outer layers of enamel. \n\nIn human dentine the trace elements of Fe, Zn, and Sr are found\n\nCollagen\nThe predominant organic component of teeth is collagen, an insoluble protein present in the dentine and basal plate of the mature tooth. Also the most abundant protein of vertebrates, collagen has evolved to perform a very specialised structural role. \n\nThe amino acid sequence of collagen, which comprises some 20 different amino acids, is highly repetitious. Thus, very characteristic is the repeating tripeptide sequence: Gly-X-Y, where X and Y can be any amino acid, though X is often Pro and Y often Hyp. Of the collagen residues almost 30% are glycine and a further 15-30% are proline and hydroxyproline. The primary structure adopts a left-handed helical secondary structure. \n\nThree parallel helical polypeptide chains wind around one another forming a triple helix, with every third residue of the individual polypeptide chains passing through the centre of the triple helix. Only a Gly residue is small enough to fit in this position and so explains the requirement of Gly as every third residue along each polypeptide chain. The special quaternary structure of the triple helix is of the form of a right-handed supercoil, the Gly residues on the neighbouring polypeptide chains tracing out this right-handed path. \n\nThe collagen supercoils (right-handed triple helices) align in a parallel, though staggered, arrangement. This array is called a microfibril, with several microfibrils compiling a collagen fibre. The gaps in the staggered arrangement may provide nucleation sites for apatite mineralisation (Voet and Voet 1990) This is not observed for Elasmobranch teeth where fluorapatite crystals are not formed within collagen fibres but outside. This may be a result of the larger crystallite size of fluorapatite compared to hydroxyapatite in mammalian teeth. \n\nThe structural proteins and apatite of teeth need to be synthesized in an integrated way. Comparing the structure of natural helicoids such as collagen to twisted nematic liquid crystals, it has been suggested that the orientation of the structural protein in synthesis, is governed by self-assembly, thus likening the synthesis of helicoids to that of twisted nematic liquid crystals. It is also suggested that adsorption of organic matrix onto enameloid crystals may influence the kinetics of crystal growth. \n\nThe polypeptide chains of collagen are more extended than the more common a-helices of proteins. Collagen helix: pitch of 10.0A, 3.3 residues per turn; a-helix: pitch of 5.4A, 3.6 residues per turn. There is strong hydrogen bonding between the N-H of each Gly residue on a chain and the carbonyl oxygen of an X-residue on a neighbouring chain within a triple helix. Cross-links between chains of separate collagen supercoils also occur and are thought to be the result of hydroxylysine residues made into cross-links with Lys and His residues by the action of metallo-enzymes, and hydroxyproline residue cross-links, probably involving bridging water molecules. Collagen has great tensile strength with structural properties in close analogy to those of rope. A longitudinal force imposed along the collagen triple-helix is resisted laterally across the helix. This is possible because the constituent polypeptide chains (left-handed helical) run in the opposite direction to the supercoil (right-handed helical). The individual polypeptide chains are thereby prevented from uncoiling under stress. (The rope analogy) \n\nThe organisation of collagen fibrils has been developed by evolution for highly specific roles in different tissues. In teeth the collagen fibrils are suited
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Mammals have determinate growth.  This means that they will reach a certain size and stop growing.  Reptiles and many other vertebrates have indeterminate growth.  Although growth slows down with age, it continues throughout their lives.\n\nThe story of the evolution of determinate growth really takes place in the ancestors of all mammals.  So the human story is really just a throwback to that.  It's possible that it may relate to the evolution of endothermy (warm-bloodedness) and related changes involving higher metabolism and fueling that metabolism.\n\nMammals are a bit more precise a machine than reptiles in many ways.  We have complex teeth that need to fit together properly if they are to work.  The molars, premolars, canines, and incisors are quite a bit more advanced than the pointy teeth of reptiles.  With a final set of permanent teeth (particularly molars and premolars), chewing happens efficiently only when things fit together properly.  Evolution plays an important role in this, but it would be very difficult to grow in a set of teeth that would precisely fit a mouth only if that mouth were to consistently increase in size.  Instead, we are set up to get that final molar right as we stop growing.\n\n4 chambered hearts, the association between basal metabolic rate and surface area to volume ratio, lung capacity, ossification of bones, and other factors are all fine-tuned by evolution to match a general body size and increase the fitness of mammals.  An interesting aside is that when you have determinate growth, you can change body size fairly easily across evolutionary time by simply changing when you stop growing in addition to how fast you grow.  That's why you can get closely related mammals that vary considerably in size.
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First of all TEETH ARE NOT BONES.\n\n\nTeeth are depositions of enamel and dentin formed inside a tiny bud that grows(it's called a  tooth bud).  Each bud is formed like a sprout off a chain of sprouts, like leaves on a plant.  You are NOT born with all your teeth already started, but with most of them already started.   Your wisdom teeth are the last to start forming well after birth (I think 6 or 7 years) . \n\nAs part of the eruption process the new tooth (adult tooth) start to eat away the roots of the baby tooth in a controlled manner. as it takes away more and more of the baby tooth root,  the baby tooth becomes looser and falls out.   So what pushes the tooth out? The ligaments that attach the root to the bone provide the eruption force necessary for the tooth to move.
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When you eat, the digestive system breaks down food & its nutrients into forms that can be absorbed by the bloodstream; blood flows to skeletal muscles as you move them (skeletal muscles are attached to bones - these are the muscles that are controlled by the voluntary movements you make - like walking, running, clicking the mouse button, etc.). The bloodstream takes oxygen & nutrients to the muscles. \nSo, the nutrients that end up going to your muscles are dependent on what foods your eating.
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Sugar, although a good source of quick energy, is not a nutritional need for humans.\n\nHowever, many plants create sugars for their own use, and by eating those plants could early man have ingested sugar.\n\nTree sap is a resin (not sweet- even in sugar maples averages 2% sugar).  It would more likely have pulled their teeth out or cemented their mouths shut than made for good chewing.  Maple syrup wasn't made until the 1600's.  Gum is a latex derivative (not sweet), which WAS harnessed by ancient man, but by south american indians, and to make durable footwear, not for eating.  It runs in different channels in the tree and is completely chemically different than sap.
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First, I am not a scientist but a scientfic researcher. It's important to know what animals eat the seeds or fruits of flowering trees to deduce it's role in a given ecosystem. It's relationship to the other living organisms in it's environment is very important. It's also imortant to know what animals very existence hinges on the trees continued existence in the ecosytem. In other words, as trees get chopped down and various animal species that depend on the trees start to die, that is then a useful barometer of the trees role in the ecosystem.
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Well, Presently no functions are established. The theories about its unctions are there. It is said that it was functional once when human skills regarding obtaining food were primitive and they have to consume only vegitaton for food. The cellulose contained in this vegitation is not normally digested but when the apendex was functional its role was for digestion of cellulose and other such complex substance. With improvement in Food skills the cellulose part decreased and now we don't consumed scrub and natural selection eliminated the genes or they went dormant as 97% DNA is without known function.
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The tongue and throat are derived from ectoderm.  The nerves supplying the tongue are V for pain and touch, VII for taste on the anterior portion of the tongue, and IX for taste on the posterior portion of the tongue.  XII is the motor portion of the tongue.\nIn general sensory neurons are derived from the alar plate while the motor neurons are from the basal plate.  These come from the neural tube which is an infolding of ectoderm called neuroectoderm. \nNot sure if you need to know about the pharyngeal pouches.  If so you might read up in a medical embryology text.  I can't remember them off the top of my head but if i had to guess i'd say it was the 2nd pharyngeal pouch.
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If you're referring to a human skeleton, yes, a good approximation can be done because our teeth have limited growth (they're brachydont) and we only have 2 generations, like most mammals. Therefore, an expert could see if the teeth are part of the milk or definitive dentition, and also assess the wear of the occlusal (grinding) surfaces. And not only the external appearance of the teeth is examined, but also the tissues (dentine, cement, enamel, pulp cavity).\nThere are standards to calculate age and they're normally used by forensic experts.\nA list of bibliography on the subject:\nhttp://users.breathe.com/malt/agedet.htm\nI've tried to find articles but none are free :-(\n\nHowever, other mammals have permanently-growing teeth, and therefore age determination is more difficult. And in other vertebrates that have more dental generations, other methods are used for age determination.