And God created great sea creatures, and every living thing that moves, which the waters brought forth abundantly, after their kind, and every winged fowl after its kind: and God saw that it was good.
All Commentaries on Genesis 1:21 Go To Genesis 1
Basil the Great
There is nothing truer than this, that either each plant has seed or there exists in it some generative power. And this accounts for the expression “of its own kind.” For the shoot of the reed is not productive of an olive tree, but from the reed comes another reed, and from seeds spring plants related to the seeds sown. Thus what was put forth by the earth in its first generation has been preserved until the present time, since the kinds persisted through constant reproduction.