You're confusing what He "could" do with what He "did" do. That can quickly descend into the silly, "Could God create a rock so big that He couldn't lift it?" musings.
He has revealed what he did do. He created. He didn't just mix up a batch of goo and sit back to see what happened.
In your opinion, did God create all (and I mean ALL) animals on earth in their present form with absolutely no changes between their time of creation and now?