it unfolds according to what appears to be a maturationally determined schedule that is universal across the species.

similarly, as discussed in a later section, certain species of birds develop their bird song during a biologically determened window of time.

두 문장이 서로 연결 되는 글인데......도저히 해석이 되질 않아요ㅜㅜ
도와주세요ㅠㅠ