Is evolution just change over time?

For once I agree with Smeghead.

That would meet the dictionary definition of evolution at its most basic level, but is not a good definition for evolution as "the origin of species"

Darwin argued that all creatures we see today evolved from less developed predecessors and ultimately that everything had a single common ancestor. He also proposed that life began naturally in "warm little ponds" but "truckled to public opinion" by omitting that from Origins. The current term "abiogenesis" was coined by Huxley, aka Darwin's Bulldog.

So a good definition that reflects Darwin's beliefs would be that proposed by Kerkut as "the theory that all the living forms in the world have arisen from a single source which itself came from an inorganic form."

I think the scientific definition of evolution is "A change in allele frequency over time." So yes, that is all that is required for evolution to have occured.

Simply put, evolution is the change in allele frequencies of a population in subsequent generations.

pretty much. but new things emerge too, often built upon old ones, so it is productive change

By your definition, rust would qualify as evolution. Evolution is much more than just that.

pretty much. but new things emerge too, often built upon old ones, so it is 'productive' change