Sure it does, though not necessarily to gene X. One could imagine, for example, a mutation in the promoter region of gene B that produces a binding site for transcription factor A, causing gene B to be expressed in feathers and starting a regulatory cascade involving genes C through Z, including X.
Not what I meant; I wrote âinvolvementâ and was trying to correct the implication that 200 genes involved in X means 200 mutations. In fact, some number of the 200 genes would be involved by virtue of being involved in some subprocess of development or physiology.
But I agree that new involvement of gene X in process Y is almost certainly the result of mutation, somewhere.
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so or so the majority of traits show no hierarchy and this is very important.
by this logic any order is ok. so for instance if filaments predate scales you can say that scales evolved from filaments.
so how feathers will evolve without new mutations? ( by the way i think that the number was related to wings developmant but its not so important).
False. The heritable ones do show a hiearchy, and those are the ones that count.
No, traits that arenât heritable are irrelevant.
No, not any order is okay. Obviously the earliest derived trait is generally expected to first show up in the fossil record later than the more basal trait.
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any trait is heritable so im not sure what you referring to.
but how you decide what consider to be âmodern traitâ and âprimitiveâ one?
No, that isnât so. There are two independent sorts of data: the ages of fossils and the polarization of characters on the tree. Neither is used to determine the other. If they match well, that is, if one state is both primitive (as judged by the tree) and older (as judge by fossils), thatâs confirmation of the evolutionary sequence.
You have misunderstood.
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They surely evolved via new mutations. That wasnât the point. I was stating the fact that involvement of a particular gene (or many genes) in a new process doesnât imply involvement of any mutation at all. The simplest example is if a mutation causes new expression of a gene in the epidermis, leading to a new or enhanced aspect of feather development. This gene product (protein) could then interact with many other proteins, that are already there, to create the phenotype. Thatâs a pretty plausible, even likely, scenario during development of feathers or anything else, and it means that the proteins that are âinvolvedâ in the process were not mutated and perhaps didnât even change their expression or localization.
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even if scales appeared first in the fossil record and filaments after, we can claim for missing fossils (so in this case we can say that we just didnt find the oldest fossil of filaments yet. this situation already happened with the tetrapod tracks- we find a modern trait (limbs) before its supposed anecstral trait (transition between limbs and fins). and yet almost all agree that limbs evolved from a transitional state between limbs and fins.
so you are talking about new mutations but not on these specific genes? so or so i guess that we need a lot of new mutations to evolve a complex structure like wings and feathers. probably no less than 1000 or even more (at least few bases in every gene). so how this suppose to happen step by step if these mutations were probably neutral or near neutral?
Iâm talking about how misleading it is to move from âgene involved in Xâ to âgene that has to be mutated to evolve X.â
I donât think we know how many mutations that takes. To think scientifically about it, we would be specific about the transition we want to study (from state or structure X to state or structure Y). To go from a uniform epidermis to one that includes feathers? To go from a uniform epidermis to one that includes hair follicles? Or what?
Making stuff up is not helpful and not worth discussing.
Um⌠I think you just answered your own question.
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We find no such thing. And of course, given the fragmentary nature of the record, we canât expect a perfect match. What we find instead is a significant match between fossils and trees when large numbers of characters and taxa are considered. Thereâs quite a literature on this, if youâre interested.
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Here in Canada down feather jackets are popular for keeping warm. I have yet to encounter anybody wearing one to take to the air in free flight. Flight need not be the point of feathers. Primitive feathers, filament feathers, fluffy feathers, courtship feathers, all have immense utility apart from flying. Nor is flight a improbable trait. For a creature whose habitat is trees, the ability to glide from tree to tree without having to touch ground is huge in foraging food and frustrating hungry carnivores below. Any degree of flight opens up an ecology of niches awaiting exploitation and subsequent radiation of specialized species. Feathers are wonderful examples of fully reducible complexity, having immediate benefit with every modification all the way from fuzz to soaring feathers. And all of this is available from readily available structural proteins, especially keratin, which are already present and amenable to adaptation.
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say that we want to make a non flying object into a flying one (im talking about designed object like a walking robot). how many parts we need to add to the robot to make it a flying robot?
here it again (notice the bottom left. image from wiki):
so the first true limbs\digits appearing before the first transitional form between fins and digits (tiktaalik or close species).
im not so sure about that. as i said: the majority of what i showed show no such hierarchy.
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You showed no such thing. You donât seem to understand what is meant by a significant match in the comparison between fossils and trees. You appear to think this means the match should be pretty much perfect, and that little to no gaps or deviations must exist. That is just not the case.
Two different data sets donât have to always match exactly, to have a significant degree of match despite the fact that there are many instances of obvious disagreement between then.
You really have to start wrapping your head around this concept of imperfection in historical data.
To make an analogy, if I give you a hundred thermometers with an accuracy of 5 decimal places, and after you measure the temperature in a room with all of them, you find that youâve measured literally a hundred different values between 20.206 °C, and 20.315 °C(no two thermometers measured the exact same value), would you say that the temperature measurements are inconsistent? I wouldnât.
Even if we strictly agree that the thermometers donât measure the same exact values, I wouldnât say their disagreement undermines the use of the thermometers. I would say we can know to a very high degree of certainty that the true temperature of the room is between 20.206 °C, and 20.315 °C.
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Let me suggest that your limited familiarity with the literature is responsible.
As for the tetrapod tracks you cite, you should know that their status is questionable. See this.
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Robots are not really relevant, but I would say probably lots. What is sweet though, is that for bird wings, we do not need much by way of new parts! From your public school biology, or just basic first aid, these wing bones should look familiar enough to set your mind at ease.
You can find more details here:
So by and large, new parts are not required for wings - it is only necessary to modify the existing parts. Birds are modders!
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actually i dont. i just took an example of a single trait in about 14 different species. so it should give us a proportion about the hierarchy in general. i can take a different trait and can show you that we can get the same thing (this time with edentulism among birds/dinos species):
(image from The origin of the birdâs beak: new insights from dinosaur incubation periods)
out of 21 different lineages about half of them show no hierarchy.
so what if we are talking about a robot in a shape of a bird? do you think that by making small changes to existing parts we can make a robot to fly?
But you havenât shown that. Do you even know what it means to show that?
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If the walking robot is a cyborg theropod like, then I expect by making changes to existing parts we can make a cyborg archaeopteryx like. Why not?
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He does know. Heâs not only already been referred to similar articles, heâs even admitted that they might not be tetrapod tracks:
âindeed. just for the sake of the argument i refer them as real tetrapod tracks. they can also be something else. although the evidence for that isnt so good.â
the figure show otherwise. evolution have a prediction about traits in general. if we pick a single trait evolution predict that we should find an order like: 112233. if instead we find something like 132231 this is non- hierarchical pattern and it doesnt fit well with that prediction. so if we go back the feathers types we find something like the second order instead of the first one.
i dont think its so easy. say that we want to add a new system to that robot. say a sonar system like we find in a bat. now, any minimal sonar system need at least several parts for its minimal function. thus i dont think that we can add it by small steps.