Two closely related species of nuthatches (small songbirds) come into secondary contact and begin producing fertile hybrid offspring after a reforestation effort that connects two previously separated woodlands. Give ONE potential outcome that could follow this event over evolutionary time (1-2 sentences).
A massive population of lacewings live on a crescent-shaped island in the South China Sea. Lacewing genes flow between adjacent subpopulations that exist throughout. However, the flow of genes from one tip of the island to the other is extremely rare, resulting in enough divergence that the two “tip” populations cannot produce viable offspring. By the biological species definition we are using in this course, we can say the speciation has occurred. What mode of speciation is this? Explain your answer (2-3 sentences).
In many species of Penguins, males spend a lot of time looking for the perfect pebble to offer to potential mates in an apparent “proposal.” The most desirable female in a colony will have many pebbles at her feet from which to choose. In lecture, you have seen many other examples of species where the females are “choosy.”
3A. Compared to males, why are females most often in a position to choose among a cohort of male suitors (1-2 sentences)?
3B. What information about male quality do you think female penguins are learning from their pebble proposals (1 sentence)?
3C. Hypothesize how this courtship behavior may evolve if males began stealing pebbles from one another (1-2 sentences).
Albatross, large marine birds, have large wings allowing them to save energy and glide across the ocean for miles. They also have thick feathers to protect themselves from the weather, as it can be cold and wet out at sea. In what ways might wingspan and feather thickness act as tradeoffs for one another? Specifically, describe how having more of one trait impacts the effectiveness of the other, and vice versa (2-3 sentences).