Before revision:  Population sizes in our system follow a bimodal distribution with the lower peak composed of the recently collapsed or the newly arrived species. In contrast to this, the upper peak of the distribution consists of the surviving species in the current diversity wave.
After revision:  Population sizes in our system follow a bimodal distribution with the lower peak composed of the recently collapsed or newly introduced species, while the upper peak of the distribution consists of the surviving species in the current diversity wave.