Due to modern discoveries in breeding that enabled researchers to move genes from one species of plant to another, there was some softening of this point. After all, it was beginning to look like plants were just one big ol' species with no boundaries, and no one wanted to deal with that.
Last week's Science News carried an article about even later research that indicates there are fixed boundaries to plant species, just like there are for animal species.
Consequently, it's safe to go back to the older standard and abandon the equivocation and cant.
Bacteria and archaeobacter have a different problem. Many bacteria of quite different species seem to be able to use conjugation to pass on beneficial genes to each other (presumably for immunological purposes, or maybe they're just into mysticism). Still there are species boundaries for bacteria, and no one has seems to have observed the creation of a new species lately ~ if ever, although they are all the time discovering new ones.
Now, what might the speciation among viruses mean? No doubt they evolve, but do viruses have species boundaries?
Again, mere change is not evidence of the original Darwinian claims for evolution. Else, we are all little different than the Creationist who accept breeding dogs for various traits, but reject the idea that such change might well end up with something other than a dog.
True, but all change between generations is minor. Always. There is never a case in which a child is a new species from the parent. Never.
Since species transitions typically take thousands of years minimum, and changes on the order of what creationists would like to see demonstrated may take much much longer, these events don't take place on a time scale short enough for direct observation.
There are examples of populations that are diverging in an incipient speciation event. Two examples I've read about recently are with a species of frog and a species of abalone.
Sorry evolution is defined as ongoing change and it is a fact that applies to more than evolution. The theory of evolution observes the fact, evidence and empirical evidence for the fact and provides a explanation for the fact.
In the life sciences, evolution is a change in the traits of living organisms over generations, including the emergence of new species. In other fields evolution is used more generally to refer to any process of change over time. Web definition
The the theory of evolution presents evidence and empirical evidence that the fact (evolution or ongoing change) explains the origin of the species. Evolution is both a fact and a theory.
Darwin said this almost 150 years ago. This is from Origin of Species (6th ed.), Chapter 2 - Variation Under Nature:
The many slight differences which appear in the offspring from the same parents, or which it may be presumed have thus arisen, from being observed in the individuals of the same species inhabiting the same confined locality, may be called individual differences. No one supposes that all the individuals of the same species are cast in the same actual mould. These individual differences are of the highest importance for us, for they are often inherited, as must be familiar to every one; and they thus afford materials for natural selection to act on and accumulate, in the same manner as man accumulates in any given direction individual differences in his domesticated productions.