Study Questions for Sex Determination and Differentiation

1. What is an organizational effect? Describe how the song bird brain is organized by the relevant hormones. Be specific about which hormones are involved in the cascade of events. After these organizational events, how does a male bird learn his song?

2. What is an activational effect? Describe how maternal behaviors in mice are activated by hormone interactions. What is the environmental trigger for nuturing behaviors? Is nurturing under genetic control?

3. What is a maternal effect? How is this different from genetic alteration of phenotype? What are the advantages of a system in which the female can alter offspring via a maternal effect, compared to hard-wired genetic differences?

4. How does the phenomenon of sex change in the stoplight parrotfish span the spectrum of male and female reproductive phenotypes? Describe the mechanisms of sex change (with diag. of hormone profile) in terms of the principle male and female hormones found in fish.