Let me say this a little differently. We know the current mutation rate in many organisms today. We have no reason to believe that was once lower. You can't study origins of each new kind and know the population size that is pure fantasy. I am not disputing studying groups that exist today. I would say and probably most would agree me,with each new kind the population was small, Small isolated groups would be at serious threat of survival with the problems mentioned.
You are ignoring several important facts. First, most mutations are benign. Secondly, even in small populations, beneficial mutations confer a survival advantage. Third, most species produce more offspring than are needed to pass on their heritage, which increases species survival rates. Fourth, and this is where my work comes in, I've studied crinoids most of my life, and am an expert in echinoderms, having collected many fossil specimens and raised live echinoderms. While there are no living crinoid species that can be found in, for instance, Paleozoic faunal zones, all three classes are present from the Ordovician all the way to the present. That is 400 million years of evolution of all three classes of crinoids. And so when you say that you can't study their evolutionary history because you can't know the population size, I say you don't understand how population surveys are conducted. My specialty is middle Mississippian aged crinoids (late Osagean stage, to be precise). My paper I linked to in a previous post described 66 species of crinoids representing over 20 genera from all three classes, including 8 new species. The fossil bed where those specimens originated is nearly 80 feet thick and represents millions of crinoids. And so the samples of specimens was truly representative of one of the largest and diverse crinoid fauna that existed 330 million years ago, that ever existed, in fact. So yes, you certainly can know in detail the fossil population you are working with. You can even determine the currents, the depth of the water in which they lived, the substrate on which they lived, and the entire population of the rest of the flora and fauna that made up the reef in which they lived. Also present in that fauna were sharks, trilobites, blastoids, sea urchin-like animals called echinoids, and even sponges. From that survey, we could reconstruct nearly the entire reef habitat, and compare what we found at that site with other similar sites throughout the Midwest. And you can compare and contrast all of that with modern crinoid reefs today.
That is not quite accurate. For instance, the coelacanth has been around for at least 300 million years. But the coelacanth that existed back then is not the same species as the one that existed today. There is only one species alive today and it is not represented in the fossil record.
You might say so what ? but every group of organisms are experiencing these mutations and natural selection and we are not seeing new kinds being developed.
Yes we are. In great abundance, and throughout the classification scheme.
