Why heirarchical taxonomy? Linnean system vs. Phylocode?

why? because it is the best way to differentiate species that we currently have. without some system then every creature is a human being.there are efforts to revise it from the old system to one based on genetics, but this is not raising too many {hackles\problems}, mostly because the genetic tree of life matches the old one pretty well (something like over 99% if I read another post correctly)for more on the current classification system go here: http://www.msu.edu/%7Enixonjos/armadillo/taxonomy.htmlyour definition of species is also incomplete, as it makes no reference to non-breeding behavior as a barrier to reproduction even while breeding is genetically possible.the horse and the donkey do not, left to their own devices, mate: they have to be tricked (usually raising one only in the company of the other) to do it.they are not alone. there is also the asian greenish warbler that has several subspecies that make a continuous ring around a high area in tibet, overlapping in china with two subspecies that do not interbreed even though all other overlaps between subspecies do interbreed. the behavior of these two subspecies is different enough that they are not viewed as potential mates.see http://www.zoology.ubc.ca/~irwin/Greenish%20warblers.html for moreit is not natural selection (survival) that is making this happen, but sexual selection.meanwhile I have yet to hear one clear definition of what "kind" represents ... it used to be variety, then it became species, then it became genus and is currently flirting with family if not order.this is due to defining "kind" as the upper level where evolution has definitely been observed so as to make "macro"evolution questionable.when it comes to the bear, the paleontologist has a framework of species from which to work, complete with timelines for the different species that are known.see http://www.geol.umd.edu/%7Ecandela/pbevol.html for some of the information.thus the paleontologist will be able to compare his bear to the others and see how it relates, how that fits with the time line and whether or not it provides new information that can lead to new theories or that challenge old ones.this picture is for horses, but the same sort of thing can be developed for any group of related species: the creationist likely says "it's a bear" and is usually satisfied with the answer, seemingly unconcerned that at some point "it's not a bear" becomes evident in the fossil record, along with "there are no bears there" before a certain date (as in no bear fossils appear in the geological record below the iridium layer that blanketed the earth only 65 million years ago).I'll choose a well defined system that has some problems, knowing what the problems are (and the work being done to resolve those problems), rather than an undefined system that not only cannot provide any information, but doesn't provide a framework for determining information, and say thanks.this is said, knowing that at the other extreme, like the asian greenish warbler, we are all related to past species by a chain of small changes that wouldn't even be enough to warrent classification as a different variety, and thus if we only look at the changes within a brief period of time while delving further and further into the past we will find a continuous line of one "species" from human back to bacteria, as well as a similar line for virtually every other critter on earth. this obviously does not give us a framework to map out species, evolution and changes over time, so usually some point is reached where we draw an, albeit arbitrary, line that in essence says "we believe that the total changes between {that} species and {this} one are sufficient that should they happen to coexist we would classify them as different species" and thus break the line into a chain with links that are connected but where each link is distinct enough to distinguish and which only covers descrete segments of the lines of continuous life. this solves the messy {we are all one kind} question and sorts the data into useful bits.hope that helps.enjoy.This message has been edited by RAZD, 04*06*2005 08:01 PM

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we are limited in our ability to understand
by our ability to understand RebelAAmerican.Zen[Deist
{{{Buddha walks off laughing with joy}}}

perhaps a little confusion on both parts ...both linnean and phylocode are nested systems of categorizing species in the tree of life, with phylocode bringing in more of the genetic evidence and structure. the tree of life with known problems and the work being done to fix it ... versus "kind" categories"kind" is not a nested system or even a system of relations, so comparing it with either is false.I found this site of interest
http://www.ohiou.edu/phylocode/index.html

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we are limited in our ability to understand
by our ability to understand RebelAAmerican.Zen[Deist
{{{Buddha walks off laughing with joy}}}

We'd have to look at the DNA or what passes for DNA in the XT'sif there was no comparison then it would be pretty obvious that a whole different tree of life had flourished elsewhere and that there would be not rational reason to include them in our little shrubif there was a comparison then some pretty big questions would be raised eh?did life come from some other common source or is DNA an inevitable result given the proper seed conditions?

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we are limited in our ability to understand
by our ability to understand RebelAAmerican.Zen[Deist
{{{Buddha walks off laughing with joy}}}

what??you're saying there is no such thing as macroevolution???I'm shocked! SHOCKED!!!!!

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we are limited in our ability to understand
by our ability to understand RebelAAmerican.Zen[Deist
{{{Buddha walks off laughing with joy}}}

more like macroevolution=n*microevolutionsame process, just more of it. and looking at genetics that would be born out: the only difference at a genetic level is more change between more diverse species than between closely related species in a consistent patter that also matches the pattern of division in time.now if we reduce taxonomy to only the differences between species this would be like discussing the leaves of a tree and ignoring the brances. there are many cases where neighboring leaves come from fundamentally different brances.