Species do transform out of necessity. If there is no real necessity, they don't change.
You are just repeating the contradiction. If they do change out of necessity then those that do not change should die and we would not have all these old species around. Let's remember also that because the more advance species are sexual, they require mates to reproduce so this requires that not one, but several (or perhapse the whole species) transform itself into a new more advanced species. There is also a great vacuity inherent in this argument from necessity. Need does not produce new genes, it is not a cause for new functions, just because one needs something does not mean it magically appears which is in essence what evolutionists are saying with this argument.
If they succesfully occupy an ecological niche, they multiply and prosper. Frogs as a class occupy certain specific places in the ecosystem. They do not compete with alligators or chimps, and in fact are depended on by other species as a food source. Plants were not "replaced" by animals. Animals in fact require plant life to survive. If a group of species like frogs is more succesful in their niche than a competing species of reptile, the frogs win. It doesn't matter if the reptiles are more "advanced" in some ways. As far as competing for food and reproductive capability, frogs do fine.
Frogs may not compete for food with alligators, but they may indeed become food for the alligator. This is one of the many kinds of competition which evolutionists postulate as the source of evolution, they call it the 'struggle for life' and it involves dog eat dog, dog eat mouse and dog eat the food of another species. In fact evolutionists call this all part of the environment which creates the necessity for evolution. And again one must say that no place on earth has not been to either environmental (weather, etc.) changes and the competition between species for 200 million years. Therefore it cannot be said that a frog or any kind of species that has remained unchanged for hundreds of millions of years does not disprove evolution.
I think you would be hard pressed to find a specific species of frog that has survived virtually unchanged since the emergence of the class millions of years ago.
I already gave you an example of just such a frog, with citation and link to the site. It is not just this frog though which has not changed for hundreds of millions of years. The reason we can identify these supposed 'evolutionary ancestors' of more developed species is that they are virtually unchanged since their first appearance!
I really don't know how better to explain it. We'll be beating a dead horse if we keep up discussion on this particular topic much more.
Let's remember also that because the more advance species are sexual, they require mates to reproduce so this requires that not one, but several (or perhapse the whole species) transform itself into a new more advanced species.
Major misconception here. Species do not suddenly grow extra limbs in one generation. They do not "spontaneously" morph into something else. Most evolution has to do with features that are common in the species to begin with. Say that due to a change in the enviornment, taller members of the species have an easier time surviving. Gradually the speicies will tend to get taller. These enviornmental changes may not happen often, so species have no reason to change wildly. There are built-in resistances to most mutations, making variation relatively uncommon, so unless there is a definite pressure, there is no reason for something to be constantly changing.
Frogs may not compete for food with alligators, but they may indeed become food for the alligator.
Just because there is a predator/prey struggle, this does not imply a struggle for resources. Predators depend on prey species for food. If they eat too many and the prey become scarce, they starve and become scarce themselves. If the predators become scarce, the prey can overmultiply and the whole cycle starts again. This interdependence is critical, so there is no reason why alligators MUST eat frogs to extinction simply because they are more "advanced". I've said it before and I'll say it again: Just because a species is more complex, doesn't make it superior. You might not LIKE this fact, but that doesn't make it not true.
I already gave you an example of just such a frog, with citation and link to the site.
Please re-post it then. The last link I could find that you posted was back in 393. Something about puffer-fish.