I have rarely found such assumptions to be valid. One is not acting in good faith if one avoids correcting misconceptions.
I think perhaps that we should let haryonob explain what s/he is thinkingā¦
Iām hardly new to these sorts of discussions, and you guys regularly amaze me at the things I donāt know. 
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(cough cough) Incipient speciation. 
Genomics of Rapid Incipient Speciation in Sympatric Threespine Stickleback
As Will Rogers famously noted: āeveryone is ignorant, just in different subjectsā.
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Are they separate species?
Is it your point that it can be hard to say whether theyāre separate species? Or that we canāt tell whether they will eventually become separate species? Nevertheless, if we can agree that this is the sort of thing that happens during speciation, Iād say that it is indeed āstarting to undergo speciationā, regardless of whether that process will actually end up in speciation.
Ahem
Are they starting to undergo speciation? What does the word incipient mean?
Sorry I have been too vague, @swamidass is right. I have understood that the initial function of the feather was not related to flight. It was most likely for sensory vibrae / thermoregulation. The initial mutation could have also been recessive for millions of years.
What I poorly wanted to get accross, is that whether Inbreeding is a factor in order for chickens to become chickens, and ducks to become ducks, assuming a common descent. It seems the answer is no.
What I am also interested in, is whether in Nature, does evolution always result in more genetic material for the organism involved?
Finally, in regards to the conclusion of the study that I linked to, so what exactly is the effect of Inbreeding depression that occurs in the wild today?
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That also would not have arisen as a single mutation.
Iām not sure, based on this, that you know what ārecessiveā means. I think you may mean āneutralā.
No. Both increases and decreases in genetic material are common. Some taxa have long-term trends toward increase, while others have trends toward decrease, and still others have no particular trends at all. Birds, for example, have small genomes as amniotes go, and they appear to be getting smaller (though very slowly) over many millions of years.
As your source mentions, population extinction is a common result. Consider the poor Florida panther.
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No, not always. If youāre looking for an answer to why and when that happens, there is no short and simple answer to it. It depends on a whole host of factors, such as population size, mutation rates of different types of mutations, and so on, together with the ecological and environmental circumstances of the organism.
There are mechanisms that generate more genetic material, such as gene duplications, viral insertions(essentially horisontal gene transfer from other organisms), transposition and so on. And there are other mutational mechanisms can result in deletion of genetic material.
Then there is the processes of natural selection and genetic drift, which both play a role in determining the fates of any excess genetic material generated by the above mechanisms.
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Youāre right, āneutralā is what I meant. Thank you everyone, will have to read up on these first.
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Iām asking whether they are separate species. Can you say that they are separate species?
Can you?
Iād say that it clearly could be or even may be likely, but Iād also say that you and Tim are overselling an inference as data. That this particular case will end with speciation appears to be about as certain as chloroquine working.
Itās really, really important that laypeople understand that āspeciesā is a fuzzy human construct applied with the benefit of hindsight.
It seems that you are trying to make a point. Rather than trying out for Socrates, why not say what your point is?
We can agree that species are fuzzy, which is a necessary consequence of gradual speciation. Populations can be found in all stages from complete interbreeding to complete isolation. But Iām not sure what the point is about hindsight.
i have a problem with that progression josh. if we will look at this phylogeny for instance we can see that its not so perfect :
(image form wiki)
as far as i remember about 1000 genes are related to feathers. so if we assume about 1000 small steps to evolve feathers how much beneficial were all these steps? i think that its sound like a neutral evolution.
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The depicted phylogeny seems perfectly fine to me. The first scales are older than the first filaments. The first filaments are older than the first plumulaceous feathers. The first plumulaceous feathers are older than the first pennaceous feathers.
Thatās a textbook example of temporal fossil progression.
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actually it seems that the filaments predate scales (unless you want to agrue for convergent evolution):
even so there is at least one out of place trait. if we combine it with the evidence i showed here about āout of placeā fossils it seems that the majority (!) of traits dont fit with the evolutionery progression.
Not if you expand the taxonomic coverage to other amniotes. And just based on the tree shown, the primitive state could be either filaments or scales. Both are equally parsimonious.
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Yeah but there are more organisms in the world than those depicted. Scales are of course much older
Wrong. The only thing required to show a progression is that more basal traits (plesiomorphies) predate more derived traits (apomorphies). There is no requirement that all fossils from descendant lineages must be found to have preserved or even retained the derived state.
For that the fossil record would have to show perfect preservation of traits, which would be unreasonable to demand.
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Thatās probably a fivefold overstatement. See this paper:
We wouldnāt assume that. The involvement of gene X in feather development does not imply any necessary mutation at all.
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