Spring 2014 MIDTERM #1Write Full Name on BACK______Fill in the Blanks (2pts each, unless otherwise noted)1. (4pts) Researchers in the 1980s implanted female zebra finch chicks with estrogen (estradiol) and noted a change in their brain physiology and behavior as adults. Describe how the brains of these estrogen-implanted females differed from control females (2pts): ____they had higher numbers of neurons in the HVC (or higher vocal center). (also permissible for 1 pt = male-like brains)__ __.And speculate as to which behavior they were observed performing that the control females did not perform (2pts): _____singing (or courting other females)_ ___ __________________________________________________________________.2. What is the physiological mechanism that allows salmon to geographically imprint onto their natal tributaries? __Their olfactory system (olfactory epithelium) produces more receptors that match the chemical signals in their natal stream; allowing them to search for this scent later on in life (their olfactory system is primed for this scent).3. (3pts) What hormone helps mediate social memory in male rodents__oxytocin________________; what two behaviors does it help regulate in female rodents? ____maternal care & partner bonding______________________________________ 4. (3pts) The above experimental results are from a selection experiment in which they raised Drosophila larvae in high and low density populations. Name the gene responsible for the different responses?:(1pt) ____for__________. Based upon the results, what selective forces appear to maintain two alleles for this gene in nature? (2pts) ____differences in population density (also acceptable = highdensity favors rovers; low density favors sitters). ________________________________________________________________5. (4pts) It is assumed that the ancestral mating system of voles involved polygyny (males controlling groups of females). Speculate on a BEHAVIORAL response by females that could destabilize polygyny (2pts); and a subsequent Male Behavioral Response that could lead to monogamy (2pts): _____Females could become promiscuous (which leads to male uncertainty of paternity); Males could then mate guard (to ensure paternity) ____________________________ ___________________________________________________________ 6. Hearing her partner and her own self “coo” produces what physiological effect in a female ring dove? ________increase in follicular size_(or increase in egg size)_; (also acceptable: increase in estrogen (for 1 pt)____7. What is one common property of Ritualized Threat Displays across the animal kingdom?_____they escalate in terms of potential for physical harm (they start with minimal physical contact and then increase towards behaviors involving more contact and the potential for harm/ costly behaviors) _______________________________________________ 8. What enzyme converts testosterone to estradiol in the brain? _________aromatase________________________________ _______________________________________________________9. Above are the results of an experiment that Niko Tinbergen conducted on peckingbehavior in herring gull chicks. The painted red artificial ‘bill’ in (D) above received the highest number of pecks, even moreso than the natural bird head (A).What is the name of the type of stimulus represented in (D): ____________ _________Supernormal stimulus (or Supranormal stimulus)_____ __________________________________ 10. Define a Fixed Action Pattern: _an innate behavior that once triggered by an a stimulus (a releaser) continues until completion 11. Both monogamous and polygamous bird species have multiple broods in a breeding season. In which species would you expect the males to show cyclical patterns of testosterone production, rather than constant levels? ________monogamous___________________________________________12. (6pts) Provide an example of a species where it has been shown that hormones modify the sensory system (2pts), briefly describe how hormones specifically affect the sensory system (2pts), and explain why at an ultimate level this might be adaptive (2pts): _____ Possible answers: (a) midshipman fish auditory system can be enhanced by sex steroids (estradiol or testosterone—either is fine), the specific enhancement is in the temporal frequency tuning—so that females can hear the timing components of the male hum/call. This may be adaptive as whether or not a male can hum (contract his swim bladder quickly) may be indicative of his condition and hence would be an indicator of his ability tobe a good protector of the eggs/nest.__________________________________________________________________13. (6pts) Describe at a proximate level why female lions may pay attention to the darkness of a male’s mane (3pts). Then describe at an ultimate level why femalesmay use mane colors for mate choice (3pts). ____ Mane darkness (melanation) is linked the level of circulating testosterone and can be influenced by sickness and injury. If a male has a dark male, this then indicates he is healthy and has high levels of testosterone which is also linked to aggression levels in many mammals. At an ultimate level, females prefer darker maned males because this could ensure that he would have greater‘staying’ power—and be a more protective father—able to fend off possible take-overs by other coalitions that would result in infanticide and a loss of reproductive effort by the female. _14. (15 pts) The figure below depicts the average honeybee life cycle. Describe the proximate mechanisms that allow the shift from the first four stages of in-hive duties (nursing-type duties) to outside hive duties (foraging) (2pts). Explain how researchers disentangled age effects from the action of a single gene in this transition (3pts); Explain how researchers determined that it was the action of a single gene in this transition (3pts); describe the environmental regulation of this gene’s expression (3pts); and explain at an ultimate level why this gene may be environmentally-regulated, as opposed to environmentally-independent (as in another insect species) (4pts). (Please use backside to finish your essay)The progression from nurser to forager is mediated by the gene Amfor (the homologue of the drosophila for gene---acceptable to call it for as well) with greater expression of Amfor in Foragers than Nursers. The differential expression of this gene is