The other weakness in the definition is it can not account for fossil species.
For example what "kind" are these?
How do you figure out what kinds these critters are? The proposed definition of kind can not account for them.
wa:do
It seems your researchers are also confused. I'm just little old me coming up with a definition of kind that now has to solve all the riddles of fossil identification better than your own researchers can. It is a shame you do not hold your own science up to similar rigour, both as a science and in relation to your species concept .
These bird like fossils I thnk belong to the family Dromaeosauridae. Your thousand of researchers "has concluded that there is not yet enough evidence to determine whether any dromaeosaurs could fly or glide, or whether they evolved from ancestors that could" and everything below family rank is equally debated. I could not identify the last fossil. Is it Tiktaalic? I hope so, as I have already shown elewhere that there were tetrapod footprints around when tiktaalic landed that belonged to an already roaming tetrapod. So do tell me what this fossil is if my definition depends on sorting out all your evo dilemmas for you just to have a definition of kind. These are serious signs of desperation, I think, which is good news for me.
Archaeopteryx- Phylogenetic position
Modern paleontology has consistently placed Archaeopteryx as the most primitive bird. It is not thought to be a true ancestor of modern birds but, rather, a close relative of that ancestor (see Avialae and Aves).[72] Nonetheless, Archaeopteryx is so often used as a model of the true ancestral bird that it has seemed almost heretical to suggest otherwise. Several authors have done so.[70] Lowe (1935)[73] and Thulborn (1984)[74] questioned whether Archaeopteryx truly was the first bird. They suggested that Archaeopteryx was a dinosaur that was no more closely related to birds than were other dinosaur groups. Kurzanov (1987) suggested that Avimimus was more likely to be the ancestor of all birds than Archaeopteryx.[75] Barsbold (1983)[76] and Zweers and Van den Berge (1997)[77] noted that many maniraptoran lineages are extremely birdlike, and suggested that different groups of birds may have descended from different dinosaur ancestors.
...and of course there is research that suggests some dinosaurs evolved from birds.
So you are hoping that if I can't classify your old bones into a kind then my definition is bad. Well seeing as your researchers are guessing, I'll guess that the family Dromaeosauridae appears to be a kind that went extinct. That's about as robust an answer as your reseachers can supply. Now if you ever get some DNA then maybe I can be clearer, just like evos would be if they had DNA, which they haven't.
Microraptor: Implications
The unique wing arrangement found in Microraptor raised the question of its importance to the origin of flight in modern birds—did avian flight go through a four-winged stage, or were four-winged gliders like Microraptor an evolutionary side-branch that did not leave descendants? As early as 1915, naturalistWilliam Beebe had argued that the evolution of bird flight may have gone through a four-winged (or tetrapteryx) stage.[11] Chatterjee and Templin did not take a strong stance on this possibility, noting that both a conventional interpretation and a tetrapteryx stage are equally possible. However, based on the presence of unusually long leg feathers in various feathered dinosaurs, Archaeopteryx, and some modern birds such as raptors, as well as the discovery of further dinosaur with long primary feathers on their feet (such as Pedopenna), the authors argued that the current body of evidence, both from morphology and phylogeny, suggests that bird flight did shift at some point from shared limb dominance to front-limb dominance, and that all modern birds may have evolved from four-winged ancestors, or at least ancestors with unusually long leg feathers relative to the modern configuration.[3]
As you can see from the info above your researchers are unclear also. So are you trying to say that I have to categorise these old fossils better than your scientists just to have a definition of kind when your own researchers are unclear what they are and where they belong. GOOD ONE!.
I tell you what PW I can use my definition of kind just a well as you can apply your definition of species to these old fossils. As stated Dromaeosaurids appears to be a kind that went extinct.With more information I can also apply my kind concept similarly as you apply your species concept to these old bones.
Please use your 'species' definition to classify these old bones? Now we are just talking about definitions here.. Not a total framework of theories to explain the complexity if all life. Good luck to you PW, given that your researchers are confused and in debate. It is obviously not as clear cut as some would like to think it is.
Dromaeosauridae: Relationship with birds
Dromaeosaurids share many features with early birds (clade Avialae or Aves). The precise nature of their relationship to birds has undergone a great deal of study, and hypotheses about that relationship have changed as large amounts of new evidence became available. A consensus of paleontologists has concluded that there is not yet enough evidence to determine whether any dromaeosaurs could fly or glide, or whether they evolved from ancestors that could.[40]
I am keen to see how you apply your species definition (unable to successfully interbreed) to classify these old fossils. Me thinks you are trying to use unreasonable ploys to maintain your agenda here PW. Not nice, nor ethical, but rather desperate.
