homology is evidence of what? diversifying selection, common ancestry, convergent evolution or directional sel
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Homology is evidence of common ancestry.  Homology is the divergence of a structure in a commom ancestor in its descendants.  The classic example of homology is the vertebrate forelimb.  The forelimb (arm) of a human has the same bones and underlying structure as that of most other mammals such as the whale, cat, dog, horse, cow, mouse, bat, and deer (etc.).  Also homology provides a large amount of evidence that supports evolution.
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evolution has been proven by other means .
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We evolved from primates, but not monkeys specifically.  We did not evolve from birds although we do share a common ancestor with them a long ways back.  Although evolution has not been conclusively "proven" it is supported by a preponderance of evidence and accepted by the vast majority of the scientific community.  And hutsong's "evidence" against evolution is primarily fictitious.  Don't be fooled by his authoritative manner - he's still full of crap.\n\nFor a defense of evolution see my answer to this question:\nhttp://answers.yahoo.com/question/index;_ylt=AiUBrphbhCO3D7mQOX5JXrrsy6IX?qid=1006032117223\n\nAnd these links:\nhttp://www.txtwriter.com/backgrounders/Evolution/EVpage16.html\nhttp://evolution.berkeley.edu/evosite/lines/index.shtml\nhttp://fermat.nap.edu/html/creationism/evidence.html\n\nOr go to your local library and find an introductory biology book.
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There is no need to replace evolution as there is no evidence that evoultion is in any way contradictory to reality or lacking in predictive power.\n\nBTW: Shouldn't this be in biology?
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Adaptation? Evolution?
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Homology (=common origin) can be tested using criteria at various levels: anatomical, embryological/developmental, genetic...\nThe forelimbs of all mammals arise from the same cell types and embryological layers, they appear as limb buds in all mammalian embryos, they're related to the same structures (shoulder girdle, same muscles, blood vessels and nerves), and they're coded for by the same genes (especially the homeotic genes that signal for general developmental patterns). They're formed by the same bones (the bones of the hand are the ones most modified, but they're still recognizable).\nVariations of the basic pattern represent adaptations, but the simple anatomical homology allows you to recognize the bones if you see the skeleton of any of these arms and hands. Or of any other tetrapod for that matter.\n\nWhale forelimb:\nhttp://www.uvm.edu/~jdecher/Hyperphalangy.GIF\nCat forelimb:\nhttp://www.csus.edu/indiv/l/lancasterw/bio168/LABS%20BIO168-03/Lab3-post%20cranial%20BIO168-03_files/image010.jpg\nBat forelimb:\nhttp://www.batworld.org/book/images/skeleton-pg106.gif\nHuman forelimb:\nhttp://staticfiles.sabc.co.za/VCMStaticProdStage/EDUCATION/Schools/Beyond%20The%20Classroom/Ideas%20Library/Theme%20Pictures/Human%20Body%20-%20Skeleton/Arm_c.jpg\n\nPlease see the link for more on homology:
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There is no proven connection at this time, hence it being a "theory." There are definite similarities, like we share 93% of the same genetic similarities with orangutans.
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Because we didn't evolve from apes we share a COMMON ANCESTOR with other apes (we are actually a species of ape, but you were probably using the term in the common, not the scientific, sense).  That common ancestor no longer exists.\n\nFor those who say that evolution is false:\n\nScience is not about finding a single piece of evidence to conclusively prove a theory. It's about constructing theories to fit the existing evidence and gathering new evidence that supports or refutes existing theories. Evolution is supported by a preponderance of evidence. While no one point conclusively proves it, when all the evidence is considered in the context of existing scientific knowledge evolution is a well substantiated theory. Intelligent design is not.  What follows are brief explanations of some of the evidence that supports the theory of evolution.\n\n1. Vestigial structures\n\nOne example of a vestigial structure in humans is the appendix. It has no function. Removing it is harmful only in so far as any surgery is associated with certain risks (so I wouldn't have it removed just for fun, but it's because of the surgery not the absence of the appendix). An appendix is found in several mammals. In humans it is small and has no known function. In rabbits and many other herbivores it is large and is used in the digestion of cellulose.\n\nAnother example of a vestigial structure is the hipbones of snakes. Snakes evolved from quadrupeds, and some species still retain not on pelvises, but tiny protrusions of bone in a location that corresponds to the location of the legs in other quadrupeds.\n\n2. Microevolution can be observed in both a controlled laboratory setting and in nature.\n\nCreationists will tell you that microevolution does not prove macroevolution.  This is true.  However, it does provide evidence that macroevolution may be possible. Taken in the context of the other evidence for evolution, microevolution provides a mechanism by which macroevolution could occur. On its own, it doesn't prove that macroevolution occurs, but it does suggest that it is possible.\n\n3. The fossil record.\n\nAlthough the fossil record does not provide a “complete” record as fossils form only under certain conditions, it does show a gradual change in the morphology of species as well as numerous extinct species.  There are a number of methods used to date fossils, and the time period from which a fossil comes can be determined with reasonable accuracy.\n\n4. Imperfect structures (the blind spot of the mammalian eye, for example).\n\nI want to mention the bind-spot of the mammalian eye specifically because creationists often hold up the human eye up as an example of something that is too perfect to occur by "chance" (i.e. as the result of the natural selection of beneficial changes among random mutations).\n\nThere are also numerous examples where the morphology of a species is constrained by similar patterns in its ancestors (quadrupeds, vertebrates, etc.).\n\n5. Developmental biology reflects evolutionary lineage.\n\nCreationists like to bring up a man named Haeckel in response to this argument.  Haeckel suggested that development reflects evolutionary origin.  It was later discovered that several of the sketches he used as evidence over-exaggerated certain features, and some were of different embryos all together. However, many of his sketches do accurately reflect the morphology of the embryo. Haeckel's methods were sometimes wrong and his ethics were poor, but it just so happens that his theory turned out to be fairly accurate.\n\nAny developmental biologist can tell you that embryos of related species show similar morphology in the early stages of development. The point at which their development begins to diverge shows a strong correlation with the relative point at which the evolution of the two species diverged. Human embryos look similar to chimpanzee embryos for a lot longer than they look similar to ca
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evolution. Or perhaps speciation.
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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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human evolution, theory of the origins of the human species, Homo sapiens. Modern understanding of human origins is derived largely from the findings of paleontology, anthropology, and genetics, and involves the process of natural selection (see Darwinism). Although gaps in the fossil record due to differential preservation prevent the complete specification of the line of human descent, H. sapiens share clear anatomical, genetic, and historic relationships to other primates. Of all primates, humans bear particularly close affinity to other members of a group known as hominoids, or apes, which includes orangutans, gibbons, gorillas, chimpanzees, and humans. Humans and their immediate ancestors, known as hominids, are notable among hominoids for their bipedal locomotion, slow rate of maturation, large brain size, and, at least among the more recent hominids, the development of a relatively sophisticated capacity for language, tool use, and social activity.\nThe Evolutionary Tree\n\nHumans are mammals of the Primate order. The earliest primates evolved about 65 million years ago in the geological period known as the Paleocene epoch. They were small-brained, arboreal fruit eaters, similar to modern tree shrews. Primates of the Eocene epoch (55 to 38 million years ago) were similar and ancestral to contemporary tarsiers, lemurs, and tree shrews, and are classified as lower primates or prosimians. During the late Eocene, the higher primates, or anthropoids, developed from prosimian ancestors and, aided by continental drift, diverged into New World (or platyrrhine) and Old World (or catarrhine) monkeys. The branching of Old World monkeys and hominoids apparently occurred in the late Oligocene (38 to 25 million years ago) or early Miocene (25 to 8 million years ago), a time period poorly represented in the fossil record. The lesser apes (gibbons and siamangs) and other hominoid lines diverged about 20 million years ago, while the Asian great apes (the orangutan being the only surviving form) diverged from the African hominoids about 15 to 10 million years ago. Genetic evidence suggests that the ancestral lines of gorillas diverged about 8 million years ago and that chimpanzees and hominids diverged about 5 million years ago.\n\nHominid Evolution\n\nThe earliest known hominids are members of the genus Australopithecus, the earliest of which date to more than 4 million years ago. Unlike other primates, but like all hominids, australopithecines were bipedal. Their crania, however, were small and apelike, with an average cranial capacity of about 450 cc in the gracile species and 600 cc in the robust forms. Australopithecines that have been considered ancestral in the lineage leading to the human genus Homo include A. afarensis (an important skeleton of which is popularly known as Lucy) and A. africanus. The exact position of these and other early species on the hominid family tree continues to be disputed.\n\nThe first member of the genus Homo, a small gracile species known as H. habilis, was present in east Africa at least 2 million years ago. H. habilis was the first hominid to exhibit the marked expansion of the brain (with an average cranial capacity of about 750 cc) that would become a hallmark of subsequent hominid evolutionary history. By about 1.6 million years ago, H. habilis had evolved into a larger, more robust, and larger-brained species known as Homo erectus. Cranial capacities ranged from about 900 cc in early specimens to 1050 cc in later ones. H. erectus persisted for well over a million years and migrated off the African continent into Asia, Indonesia, and Europe.\n\nBetween 500,000 and 250,000 years ago, H. erectus evolved into H. sapiens. Transitional forms between H. erectus and H. sapiens are referred to as archaic H. sapiens. With the exception of H. sapiens neandertalensis (see Neanderthal man), no additional subspecies are recognized. Indeed, some scientists consider Neanderthal a separate species. Archaic H. sa
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The major lines of evidence are:\n1) the paleoenvironments the species lived in, as evidenced by the sedimentary rocks and other fossils\n2) analogy with related species\n3) functional morphology\n4) taphonomy and trackways\n\nThings you might look up are ammonites, trilobites etc
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man and monkey evolved from a common ancestor
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You have to look at evolution as a series of slight beneficial changes that are passed down through generations.  The steps from single to double circ are unknown to me, but it is more than a single big jump.
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Evolution is a theory.
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Homologous proteins are ones that are thought to be related from a common ancestral gene.\n\nHeterologous proteins would not be related, even if they perform the same function in different species.
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I wish I could say I read Phillips answer, but I couldn't maintain focus. So, risking repeating elements of his analysis, I'm going to give this question a stab, but with a biological/evoluationary bent.\n\nEvolutionary arguments have been offered for male homosexuality. For example, Symons (1979) argues that homosexuality results from a meme that takes advantage of the inborn male propensity to find sexual variety interesting. Normally this propensity would be adaptive because it would encourage males to attempt sexual relations with many women, which would result in more offspring. But a meme could parasitize this propensity, redirecting sexual interest to non-adaptive objects, as in fetishism or homosexuality. \n\nEpigenetic arguments have been inspired by work on pre-natal hormones. Dîrner and his colleagues (cited in LeVay 1994) link stress during pregnancy to hormonal effects on the fetus that would lead to homosexuality. This could be part of a mother's adaptive reproductive strategy. That is, in times of stress, when it is difficult to raise children, it may be adaptive to have some homosexual children who could help their siblings raise offspring instead of having offspring of their own.\n\nMemic and epigenetic arguments may explain some aspects of homosexuality, such as the cultural variations in practices or identities, or specific behaviors of homosexuals (femininity for example). However, the biological studies of homosexuality, together with the extraordinary cross-cultural similarities of exclusive homosexuals (Whitam 1983) suggest that some aspects of homosexuality (e.g. orientation) are at least partly determined by genes.\n\nThe basic problem for genetic explanations of homosexuality is to account for how a gene that does not lead to offspring could survive the pressures of natural selection. One possibility is that a maladaptive gene for homosexuality might re-occur repeatedly in a population if it results from the frequent mutation of a gene that is normally adaptive. However, people with maladaptive genes rarely exceed 1% of the population, while male homosexuality apparently occurs much more frequently (Whitam and Mathy 1986; Gadpaille 1980; Diamond 1993). Another possibility is that a recessive gene for homosexuality might have advantages that allow it to pass on to future generations. For example, homosexuals could directly help their relatives (who share the recessive gene) raise more children. This "kin selection" hypothesis predicts more homosexuality in those societies where homosexuals could most help their relatives (for example, in endogamous societies where homosexuals would live nearby). Nevertheless, cross-cultural research shows that this is not the case (Werner 1979). Another possibility is that a homosexual gene itself, when combined with non-homosexual genes, may provide reproductive advantages. This latter scenario is sometimes known as the "heterozygous" hypothesis, although it is really about any type of gene combination (LeVay 1994; Sommer 1990). \n\nThe heterozygous argument suggests that homosexuality results from genes for submissive behavior. An animal possessing only submissive genes would fail to reproduce for lack of trying. But an animal possessing only genes for dominance would also fail to reproduce because it would get killed for taking too many risks. It is the "heterozygous" males, who would most likely pass on their genes. By the genetic laws of probability, this would leave every generation with a certain percentage of individuals at the extremes. For example, if each of a pair of chromosomes had only one "homosexual" locus with only two possible alleles (one for dominance and one for submissiveness) this would leave a heterozygous couple with 25% of their offspring homozygous for submissiveness, 50% heterozygous, and 25% homozygous for dominance. If, however, homosexuality were the result of the interaction of five ge