what if the common designer set it up to develope but every type according to its kind?
I have not yet once heard anyone offer a very convincing definition of "kind". The word "species" comes from the Latin word for "kind". So if that were our definition then we have some problems straight away: Speciation--the arising of new species--happens and, in fact, is observed to happen.
An example of speciation in the past would be the case of the chimps, the common chimpanzee and the bonobo. Two populations of the same species have become two species.
A theoretical scenario might be thus: The modern dog is regarded as a supspecies of the wolf. The wolf is canis lupus, the modern dog is canis lupus domesticus. Through artificial selection we as humans have bred hundreds of widely divergent breeds of dogs.
What would happen, however if certain populations of dogs were isolated from others. It's impossible to say what would happen, but given environmental pressures the descendents of today's chihuahuas could become an entirely new species of canine. Even more, such a population of neo-chihuahuas could diversify, one group finding its niche one way, another group another way, and still yet another a third way. Perhaps three subspecies of neo-chihuahua, which could, again, in theory result in further speciation.
The idea of "kind" isn't helpful here. There's no limiting factor. Human beings and chimps share a common ancestor about five million years ago. That common ancestor was a kind of ape, or ape-like. Go back many millions of years previously we'll find the ancestor of all simians (apes and monkeys), and still further back we'll find the small arboreal ancestor of all primates.
Maybe something like
Purgatorius.
But then we can go back further in the fossil record, the cynodonts of which all mammals are the only surviving representatives. The cynodonts were a group of therapsid amniotic animals from the Permian about 250 mya.
Going back further we can look at the earliest proto-reptiles, the first amniotes. Distinct from their more amphibian ancestors by having the adaptation of producing eggs with which are more resilient due to the amnion. Giving these animals the ability to live further inland and spend less time out of water--indeed able to lay their eggs in land and thus safe from predation from the predators that lurked the shores and beaches.
And so on and so on.
There's no limiting factor. We call things "dogs" and "mammals" etc because we like to keep things nice and categorized for convenience. But nature is far more fluid than that. There are no rigid boundaries, certainly not ones we've constructed for our own purposes.
Birds are dinosaurs, they are the last remnants of that colossal group of animals that ruled the earth for over 100 million years until almost all were wiped out at the end of the Cretaceous 65 mya.
Mammals are cynodonts, though all other cynodonts were wiped out hundreds of millions of years ago.
Birds, mammals; and their dinosaurian and cynodont kin are all amniotes, a sort of tetrapod (a four-footed creature) which were originally a funny sort of fish, not entirely unlike modern lung fishes.
-CryptoLutheran