Part 1 of Essay
For some time she had watched his movements, appearing coyly in his haunts. And now, had it paid off? Doubtless, he was in love. His muscles were taut; he swooped through the air more like an eagle than a Greylag gander. The only problem was, it was not for her that he then landed in a flurry of quacks and wingbeats, o ....

Part 2 of Essay
.... the behavior of these large, social birds. At the same time he did not forget that all romance - animal and human - is tied intimately to natural selection. Natural selection brought on the evolution of males and females during prehistoric epochs when environmental change was making life difficult for single-sex species such as bacteria and algae. Generally, these reproduced by splitting into identical copies of themselves. New generations were thus no better than old ones at surviving in an altered worl ....