As is your norm, you've misunderstood Gould. When a paleontologist or an evolutionary biologist uses the phrase "sudden alteration" or "sudden speciation," they don't mean "sudden" in terms of a historical time frame, but in a geological time frame, i.e., "sudden" compared to what was believed previously by paleontologists and evolutionary biologists.
The early prevailing theories were that change is a gradual and steady state, without significant pauses in the process, but Gould proposed that, per species, there were long periods of relative stability, punctuated by "sudden" changes here and there, in response to the "sudden" appearance of environmental stressors. Again, "sudden" being relative to geological scales of time, not historical scales of time. To you and me, that's still extremely gradual, on the scale of millions of years for a slight alteration to be observable. In other words, even a "sudden" change on this scale would be not measurable by you even if you were born fifty-thousand years ago, and have been watching carefully till today.
And why did he invent this concept? HE didn't. Goldsmith came up with it about twenty year prior. Some called it the hopefull monster mechinism. The idea was a turtle laid an egg and a bird was hatched.
But why was this theory necessary? Because both scientists realized there are no transitional forms in the fossil record.
So what we have is evolution happend too fast in the past to leave a record and it happens to slowly in the present to observe. Very convinent.
"Only Christ is the fullness of God's revelation." Everyday Hunter
