Of course there is - a set of organisms which can reproduce and produce viable offspring. This is the only objective view of species. Evolutionists have tried to make up many other definitions so that they can subjectively claim proof for their theory. It is part of the definition game which absent evidence they use to create evidence.
As to the problem of classification, most of them are pretty well set and they express deep biological differences between species. Plants are not just different becuase they are able to photosynthesize. They require a totally different features top to bottom to accomplish this and thus are quite different from anything in the animal kingdom. Your attempt to discredit science in this manner needs to be noted. The only way you can support evolution is by throwing away science and saying that 'the facts are whatever we want them to be'.
This is not so cut and dried as you like to pretend. Right Wing is correct. Distinct speciation is a byproduct of the desire of academic zoologists' to work with convenient bounderies, it is not a reflection of natural events. In the real world, speciation is relative, gradual, and unevenly spread. One may detect relative speciation in the real world--the degree to which one individual might be likely to produce offspring with another, but one will never detect a clean line of demarcation. Mixed critters of many stripes have produced offspring with various attenuated degrees of viability. Cats&dogs, camels&llamas, sheep&goats, horses&donkeys, libertarians&republicans.
Of course there is - a set of organisms which can reproduce and produce viable offspring.
Lions and tigers, by this definition, are the same species, as are horses and zebras. Would you like to try again?