Charles Darwin, in his "Origin of Species," stated that, "If my theory be true, numberless intermediate varieties, linking most closely all of the species of the same group together must assuredly have existed ….. Consequently evidence of their former existence could be found only amongst fossil remains."
Darwin himself knew no such "transitional forms" had been discovered and hoped that they would be found in the future.
He even admitted in his "Difficulties on Theory" chapter that these missing intermediate forms were the biggest stumbling block for his theory.
He called it "the most obvious and gravest objection which can be urged against my theory."
According to the theory of evolution, every living species has emerged from a predecessor. One species which existed previously turned into something else over time and all species have come into being in this way. According to the theory, this transformation proceeds gradually over millions of years. If this were the
Blessed are the meek: for they shall inherit the earth." -Matthew 5:5