[BroJoeK]

CodeToad: "Then how do you know there are millions more not found if you haven’t found them?

OK... here is the logic behind "millions of extinct species":

Scientists estimate that the average species lives about a million years before it either goes extinct or has evolved enough to be classified as a new species.

In the world today there are about 50,000 vertebrate species (fish, amphibians, reptiles, birds & mammals).
If each species survives a million years, then during two million years there would be 100,000 species, in ten million years 500,000 species and in 100 million years five million species.
Calculating all the way back to the Cambrian Explosion (500+ mya) gives us over 25 million species.

How many fossilized species have been found?
A few thousand perhaps, certainly far less than 1% of all species which ever lived.

And that more than anything explains so-called "missing links".

[ClearCase_guy]

I estimate that, on average, there are probably — if current theories are substantiated, most likely only a relatively few estimates which may or may not contribute to the possibility that this verifiable.

[St_Thomas_Aquinas]

A few thousand perhaps, certainly far less than 1% of all species which ever lived.

And their fossils all exhibit stasis.

What are the odds that all of the discovered fossils to date exhibit stasis in species?