The following sentence is from a passage written about the fall of dinosaurs and the rise of our distant ancestors.
."..Only after the mysterious disappearance of the dinosaurs about 65 million years ago were our ancestors able to come out into the daylight in any significant numbers...."
What does "in any significant numbers" mean? Is this different from "in significant numbers"?
In groups of a size large enough to be significant.
I'm not a teacher, but I write for a living. Please don't ask me about 2nd conditionals, but I'm a safe bet for what reads well in (American) English.