"X only gives birth to its kind" is an invalid argument against Evolution

Moving continents".sounds like a tectonic shift! Before we begin, I will not be making any references to any religious text apart from the words of the topic at hand. Also I will not be putting forward arguments for creationism as that is not the topic for debate. The only thing I will be addressing is the validity of the criticism at hand. The Taxonomy classifications attributed to animals is only possible due to the extinction of all the myriad transitional species that have existed since the beginning of life. If these species still existed there would be an indefinable gradual difference between flora and fauna types. This would make it impossible for us to draw a line in the sand and delineate between their respective attributes. Taxonomy is totally reliant on evolutionary gaps for it to be a functional and workable classification system. Prior to the biological classification system that we use now, humans used different names to define and classify groups of animals - In a biblical sense this word is "kind". Biologists when classifying life are sometimes grouped into lumpers and splitters - the former grouping animals into larger groups, the later attempt to define each variation to much greater detail. The word "kind" appears to be firmly in the lumping category. and for the sake of argument let us put forward that they relate to a group of animals that are able to interbreed with each other - i.e. kind comes from kind. Although scientific taxonomy is much more granular and involves multiple layers of classifications, it doesn't preclude this system from having similar arbitrary lines drawn between different animals. This is apparent as "splitters" are always keen to claim the discovery of new animal types whereas lumpers will disagree. The problems of classification exist whatever name you allocate to an animal. This is becoming increasingly an issue as DNA evidence moves animals around the tree of life as previously established observed traits and relationships are superseded by new DNA evidence - e.g. Falcons are now considered more closely related to Parrots than to Hawks and other birds of prey. (1) When classifying animals, we do not look at a population " we look at individual examples and then compare these creatures with others of a similar biological structure. If they are suitably different, they may even get their own name " and finding a new individual specimen can be the highlight of a biologist"s career. Similarly with fossils " they are not classified in reference to a large population, they are classified based on a collection of fossilised remains of a single individual, or even sometimes only a small smattering of bones of a single individual. It is worth noting that taxonomy did not begin by mapping out the tree of life in relation to evolution and common ancestors as some would lead you to believe, rather it was purely designed by grouping living things by their shared characteristics. Names that we use commonly today for classification, such as "vertebrates" and "invertebrates" were penned by Aristotle nearly 2500 years ago. (2) As such, a dog will always be a vertebrate, not necessarily because he is descended from a vertebrate, but because he has vertebrae. Evolutionary theory does not state that fish gave birth to frogs, rather each successive generation is slightly different to the one that came before, allowing a fish like creature to evolve into both populations of fish and amphibians. (With some allowance for a bit of status every now and then) As such, over time, generations of a lineage would have to cross over the established arbitrary measures of how we define an organism/animal etc. Some biologists such as Richard Dawkins put forward that the first mammals were a shrew like creature. So this shrew (like creature) would have kept producing more shrews, but over millions of years they would cease falling into the shrew (like) category, and instead find themselves as primates, equines, or canines and the list goes on. Classification during this process is like asking what gear you are in on a variable speed gearbox (found in scooters). It cannot be defined as the arbitrary demarcations we put between classifications begin to blur So just like this shrew over time became the variety of mammals we see now, we would expect dogs to evolve in a similar manner so that over time they cease being what we define as "dogs" and become another species altogether over many many generations of mutation and natural selection. But this is not what we observe in the natural realm. We have had several thousand years of intense selective breeding of dogs and they still remain dogs despite their huge variation from chihuahua to great danes... The same for cattle, horses, sheep and the like. Alternatively, these potential new forms may still be known as "canine" but many successive layers of sub-classification would need to be added to the taxonomy so that it could then distinguish between all the variations of animals that no longer resemble what we would currently consider a "dog". There could be "dogs" who evolve to: Have pouches, Have fins, Have wings Are Bipedal Have horns Have opposing thumbs etc. etc. Through convergent evolution, their characteristics would be visually more similar to other types of mammals (although their DNA would state otherwise). Evolutionary theory teaches us that certain traits have evolved multiple times along different branches of the tree of life. Once again we can refer to the recent reclassification of Falcons who obtained their similar traits to other birds of prey independently. (1) There is no reason to think why this wouldn"t, or couldn"t happen again. Just as we are not considered a "shrew" as our distant ancestors were, a horned winged bipedal "dog" would no longer be considered what we classically consider a dog. Through gradual changes over successive generations, a species, or "kind" should morph into another kind. As we have not seen this occur in existing animals over several millennia, it is a fair criticism of the evolutionary model. We see a relatively wide range of variation within a species - sometimes happening in only a few short generations - such as the Russian Domesticated Silver Fox experiment (3) - but there is an observable limit to this variation. Direct observations should be taken with more weight than speculations on the existence of family trees that are having to unpredictably evolve themselves counter intuitively as we map the genome of different creatures. It is completely scientifically valid to use a directly observable occurrence that has been witnessed over several millennia to challenge an ever changing inference. (1)http://en.wikipedia.org... (2)http://en.wikipedia.org...(biology) (3)http://en.wikipedia.org...