[mlc9852]

Well, let's see. Humans evolved from apes or ape-like creatures so I would expect a frog to at least evolve into something more, well, grand. But in a few million more years, it might.

[Junior]

Considering humans are nothing more than a type of ape (name one feature an ape has that humans don't, or vice versa), one can figure a frog will speciate into another frog.

[From many - one.]

Nope, evolution does not have to be "upward and onwards"

A frog could evolve into an itty bitty blind parasite living in a fish intestine. None ever did that I know of, but most parasites and cave dwelling organisms seem more simple than their ancestors.

[b_sharp]

"Well, let's see. Humans evolved from apes or ape-like creatures so I would expect a frog to at least evolve into something more, well, grand. But in a few million more years, it might."

Our ancestors did it with small virtually imperceptible changes over tens of thousands of generations. We did not suddenly pop out of an ape ancestor's womb as a modern human. As has been explained many many times on this forum the speciation we see in cases such as the frog is exactly what the ToE predicts we would see.