ANSWERS to QUIZ 1-- Tosha's FRI 12:30pm SECTION

1) Define a species typical behavior and describe the role of the sign stimulus. Use a biological example (20pts).

Species have what we in the present-day terms refer to as species-typical behaviors. Such species typical displays are most clearly seen during mating, which is highly ritualized and stereotyped in all animals. Species typical displays identify a species as unique, and the information is used by members of the same species to recognize individuals as something that they might interact with. Animals also display other species typical behaviors during the activities of daily life such as foraging, preening, social interactions, however, the mating behaviors are especially stereotyped. Insuring that an animal mates with a member of its own species is critical for propagation, because hybridization betweenspecies often leads to sterility. One of the classic examples of species-typical behavior are the push-up displays of lizards. This species typical display is also a sign stimulus that elicits a "knee-jerk" reaction from a member of the same species.


2) What are the two critical conditions for sympatric speciation (20pts)?

The two critical conditions for sympatric speciation are that there be some mechanisms maintaining strong positive assortative mating and that this mating behavior is coupled with some strong selection against hybrids (e.g., hybrid unfitness). Explanation of process of natural selection and assortative mating is key.