There are still plenty of details to fill in...
I searched online dictionaries for meaning of fill in but I didn't find any fit meaning. So, could you please explain it to me?
The fuller text:
Would you jump off a skyscraper on the basis that the clash between general relativity and quantum theory means there are serious problems with our theory of gravity? It makes no more sense to question the reality of evolution because scientists are still debating about some of its finer aspects than it does to question the existence of gravity for the same reason. There are still plenty of details to fill in but, as surely as dropped objects fall, life has and continues to evolve. https://www.newscientist.com/article/dn13717-evolution-myths-yet-more-misconceptions/