They'd have to find all the intermediaries. It cannot be done. Just like speculation can be made re fish to landlubbers but nothing more than that.
There you go again, you are still not understanding the science and the roles of evidence.
Sorry, but i am going to have say this, your conclusion that “they must have all intermediaries”, is utterly and absurdly IGNORANT!
Ignorant because you are letting your bias in your religion clouds any logic you may have.
To have “all the intermediaries”, wouldn’t be achievable in fields of natural sciences, not just in evolutionary biology. You are ABSURDLY DEMANDING FOR THE IMPOSSIBLE, PERIOD
Let say you are tracing your own family tree, and say that you cannot find any more records beyond 20 generations of ancestors on your mother’s side (about 5 centuries), but only 14 generations on your father’s side (3 to 3.5 centuries).
Would that mean your 20th generation ancestor (on your mother’s side) would have no parents and no grandparents of his or her own?
Did your the 20th generation ancestor simply pop into existence without father and mother, without grandparents, great-grandparents, etc?
Plus, each person has two parents, 4 grandparents, 8 great-grandparents, 16 great-great-grandparents, and so on. My point is that with each past generations you go back exploring your family tree, the numbers of your ancestors will keep doubling in numbers. I WOULD HIGHLY DOUBT YOU HAVE RECORDS OF EVERY SINGLE ANCESTORS.
The things with tracing family trees, you won’t be following every single branches. There is really no single line, there are many.
And if you are missing knowledge of your ancestors, would you need to resort to supernatural explanations of your own ancestors?
You seriously don’t know how absurd you sound, making ultimatum that “all the intermediaries”.
And just because the picture isn’t complete, it does mean you have to give up on sciences and rely on miracles of nonexistent deity. Science may not always have answers, but is any religion better with answers?
When I look at back what I used to believe, like the Bible, today, I realized just how stupid some of the authors were, like with the book of Job. Whoever wrote Job was a bloody idiot with no understanding of nature; Job relied on the stupid “God did it” to extreme level of backward thinking.