Why haven't we observed mutations of new body parts?

That may be true. It's a function of the deep specialization prevalent in the field of biology. By the time you have a Ph.D. and you're doing research in your field, you might find yourself quite divorced from the fundamentals of biology, to the point where the questions a freshman might have - for whom it's all new - might very well be stumpers.There's quite a few Ph.D. biologists around here, incidentally, many with a focus in evolution and genetics. (Myself, I'm just an interested layperson and sometime student.)

your answer is unsatisfactory
please give a justifiable answer

Welcome sandeep,Glad you decided to add to our diversity. We have a wide variety of forums for your debating pleasure.If you find a poster's conclusion to be unsatisfactory, it is best to address why you consider it unsatisfactory and provide support for your position so that the discussion can move forward. You can use the edit key if you choose to add to your post.As members, we are guests on this board and as guests we are asked to put forth our best behavior. Please read the Forum Guidelines carefully and understand the wishes of our host. Abide by the Forum Guidelines and you will be a welcome addition.In the purple signature box below, you'll find some links that will help make your journey here pleasant.Please direct any questions or comments you may have concerning this post to the Moderation Thread.Again, welcome and fruitful debating.

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Usually, in a well-conducted debate, speakers are either emotionally uncommitted or can preserve sufficient detachment to maintain a coolly academic approach.-- Encyclopedia Brittanica, on debate

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This has been a great discussion, although I'm not sure that the original poster's question has been addressed. It seems to me he/she was asking why we have not directly observed a new limb or appendage springing forth in a species.The answer is fairly simple: The timescale required is too long. Evolution has been going on for 3.5 to 4 billion years on this planet, and we've only been studying it for a few hundred. You will not, in your lifetime observe a new limb springing up because you won't live long enough. Because of the timescales involved, we cannot study macroevolution directly. Therefore we must rely on evidence provided by the fossil record, which provides many many examples of new organs and structures developing over millions of years. Refer to the earlier discussion of Arm/Wing evolution above.

Welcome to the fray aviator79 Not sure Forever is still around to follow up either. Know of any good sequences?Enjoy.ps - as you are new, type [qs]quotes are easy[/qs] and it becomes: or type [quote]quotes are easy[/quote] and it becomes:

quote:

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quotes are easy

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also check out (help) links on formating questions when in the reply window.Go to Proposed New Topics to post new topics.Note threads are limited to ~300 posts (fyi)

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I'm not a biologist by trade so I don't know if I can bring up any which have not already been pointed out ad nauseum. I'll fall back on one that's already been brought up in this thread: arms->feathered arms->crude wings->better wings->aifoil-shaped wings.Here is a more detailed example:
Evolution of cetaceans - Wikipedia

That's a good one, alright. I was hoping to add one to Plausible Evolutionary Chains for Educational Use ... a better place for this discussion, as it is not on topic here, Enjoy.Edited by RAZD, : ot

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Do we really have examples of the transitions all the way through? For wing devopments? It seems that wing development in entomology hasn't been addressed, and this should create a bigger problem to evolution than whatever ornithology could pose.

Actually it has. The insect wing has evolved several times in several different lineages. One of them is discussed herehttp://www.rps.psu.edu/jun95/marden.html

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TO test this hypothesis, Marden and Kramer collected stoneflies from the banks of Bald Eagle Creek, near Julian, Pennsylvania. From January to March, they spent cold afternoons wading thigh-deep through freezing streams, scooping stoneflies into plastic jars. Once back in the lab, the flies were given various challenges to their flapping ability, including lower temperatures to decrease muscle efficiency and smaller wing areas (via scissors). "We couldn't change things like the neural pathways," Marden says, "so we worked with what we could change."

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Marden and Kramer discovered that skimming speed increases directly with wing area, temperature, and muscle size. Yet even severely handicapped stoneflies, with wings trimmed to one-fifth their original size and operating at temperatures just above freezing, were able to skim. "They buzzed along quite well," says Marden.

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The clipped wings approximated the size of external gills found on species of both living and fossilized aquatic insects. In an effort to find stronger correlations between wings and gills, Kramer has begun studying scanning electron micrographs of wingvein cross-sections, examining the thickness and shape of veins in various species of stonefly wings, which would strengthen his argument that the wings developed from gills.

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Also see
http://cac.psu.edu/~jhm10/movies.html
for quicktime movies.Enjoy.

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I don't know much about evolutionary biological development, but I was under the Impression that wings were present in insect ancestory since the beginning of it's divergence from Crustacea. The insects that do not have wings evolved to that stage from winged ancestors (i.e. siphonaptera from mecoptera). I thought that Stoneflies had evolved from a protelytropteran like ancestor along with many other major orders of insecta all containing wings.Wouldn't it be pointless to try to experiment on wing development on an insect that is believed to have recieved it's wings from an ancestor of a different taxa? I believe that my information is dated, and I would be very grateful if you could give me a link to a better phylogenetic tree.Aren't Stoneflies on the Neopterous stock and the "...other aqautic nymphs..." that Matthew Holm is referring to in the Paleopterous stock. So these insects aren't even monopyletic right? Then what would be point of even mentioning examples from other insects if it isn't even in the lineage of the insect in question?If your statement is true than why would James Marden be expermenting with wing development when he could be studying the evolutionary development of the stoneflies feet. [qoute]...the feet are covered with water-resistant hairs and are filled with gas[/qoute] Which seems to be very specific to the stonefly. Is it because if the feet were not how they are now the stonefly would have no way to float on the water? It kinda creates an irriducible complexity issue. If it weren't for the feet than the wings would be pointless, why doesn't the biologist try to tackle the harder question? If he solved this tougher question than his hypothesis would be easier to prove.Thank you so much for the links I really enjoyed watching the videos.

Oops! I never gave the link to the Insectal phylogenetic tree I was using.here it is Britannica

I do know that wings have evolved, been lost and evolved again on certain insects (Walkingsticks for instance), but I'm pretty sure the first insects did not have wings:http://www.apologeticspress.org/articles/2534

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They supposedly originated in the Silurian Period, which lasted from 435 to 410 million years ago. The earliest known fossilized insect is said to have lived in the Devonian Period, which began 410 million years ago. Then suddenly, around 300 million years ago, winged insects appear in the fossil record.

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(note creationist source)http://dml.cmnh.org/1994Oct/msg00116.html

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The study of insect evolution is hampered by a gigantic gap in the fossil record. Although fossils of early nonflying insects have been found in sediments dating from the Devonian period nearly 400 million years ago, no insect fossils have turned up from the following 75-million-year period.

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Marden said that fossil insects reappear in strata 325 million years old, but by then they had evolved greatly, and their increased diversity suggests that at least some species had left the water to colonize land. Many of the fossils of that period look like present-day insects, including grasshoppers.

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http://www.kendall-bioresearch.co.uk/fossil.htm

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The oldest insect fossils so far discovered are tiny imprints of wingless insects found in sandstone rocks of the mid-Devonian period (c. 380 million years old). These earliest fossils closely resemble modern springtails (Collembola) and even by this time they show most of the specialised evolutionary features that characterise the present-day members of this insect order (e.g., the reflexed 'tail' used for jumping). This would suggest that the insect-stock from which they arose must have been already very old in Devonian times, and that the first primitive wingless insects probably appeared much earlier, at least in the Silurian, around 410-440 million years ago.

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The earliest fossils of winged insects come from the coal-measures of the mid-Carboniferous (c. 320 million years old). These include the remains of cockroaches (Dictyoptera), some of which are little different from present-day species. It would seem that this group have survived more or less unchanged perhaps from Devonian times (i.e., for about 360-400 million years). The same coal deposits also contain the fossils of diverse archaic insects belonging to ancient lines that, unlike the cockroaches, gradually disappeared before the end of the Paleozoic era, leaving no modern descendants. Many of these archaic forms are huge dragonfly-like insects, with a wing-span of 20 cm or more, like the Palaeodictyoptera and Protodonata illustrated below - true 'dinosaurs' of the insect world.

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But there is a gap in the fossil record during the time period where wings first evolved. Because it is one way wings may have evolved. Why? Lots of bugs have the ability to walk on water, and a way of creating bubbles with hairs that take advantage of the surface tension of water is not a difficult process: furry foot, bubble, walk on water, "Jesus this is cool." Enjoy.

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True lots of bugs have the ability to walk on water, but none share a common ancestor with the stonefly. For example water striders belong to a completely different stock. Personally I think it would be exciting to see what scientists come up with!Thank you for the pdf file I am unfamiliar with the different subfamilies(I think), so I will have to research each name and it will take me a while.It almost appears that scientist are just not that interested in insect wing development, and there hasn't been any major theories that have been experimented on. As a creationist I don't see why we haven't majorly questioned the Darwinian theory from this angle. A lot of times creationists attack evolution on what seems to me to be a "long shot".I am still trying to familiarize myself with certain "Evolution terms" such as the Cambrian explosion. Would insect wing development be apart of this explosion? Is this term even viable anymore? And what is the dating that this supposedly happenend?

No, the beginning of the Cambrian period predates insects. This term can be very misleading, as the "explosion" is on a geological time scale covering millions of years. It refers to a sudden (in geological time) diversification of fossilized body types near the beginning of the Cambrian period, around 530 million years ago, and fossils are found in deposits like the Burgess shale.See Cambrian explosion - WikipediaPart of the issue of the "explosion" was that this is when easy to fossilize hard parts (skeletons) were first developed, while soft bodied predecessors don't fossilize as easily, thus resulting in a bias in the fossil record. That is an important part of the learning process. Keep in mind that you need to use words (like evolution) the way the scientists use them to be talking about the science, so understanding the terms is critical. Keep an open inquisitive yet skeptical mind and you will do fine.Enjoy.

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Thank you very much I enjoyed the conversation