EXAM KEY: these are examples of good answers written for this exam.

Section I. Answer either Question A or Question B. NOT BOTH.

A. This is Figure 2a from the Helbig paper. Use this figure to state the following with regard to that paper:

a. What question was asked?

- How do blackcaps determine the direction to fly during migration?

b. What hypothesis was being tested?

- A blackcap’s sense of migratory direction is innately genetic based because of an ultimate causation that provided better survival to each set of birds (i.e. not travelling across a big body of water).

- Researchers were testing the hypothesis that migratory directional orientation in 2 blackcap [populations] was additive (and thus that it had a genetic basis).

c. What prediction from the hypothesis was tested?

- Birds from the FRG are mated with birds from eastern Austria; their offspring will migrate, on average, somewhere between the two normal migration spots of each parent.

- They predicted that if they cross-bred birds from 2 black-cap [populations] which displayed different migratory directional orientation, the average migration direction would fall in between the average of mean direction of parents (that is, that variation is additive and thus heritable)

d. How would Popper view this prediction? Does it meet his standards? Why or why not?

- Popper would like this prediction because it is specific and falsifiable. If they do not observe consistent with their prediction, they may reject their hypothesis. Either way, this study is futuristic [heuristic], meaning it opens the door to more questions.

- Popper believes that a true hypothesis must be falsifiable. The researchers could have found that migratory directional orientation was not additive in the black cap species and thus without a genetic basis. So because their hypothesis could have been proven wrong, it meets Poppers standards.

B. In the paper by Carazo, there are two experiments. Explain the following:

a. What is an ultimate explanation for a behavior?

- An ultimate explanation for a behavior is the “why?” of how something comes to be – either the phylogenetic, or natural selection and environmental conditions that cause a behavior. Ultimate questions deal with population changes over time.

- Ultimate causation deals with how a behavior evolved. Specifically, it explains why a behavior is advantageous to the individual with regard to fitness and natural selection.

b. Which of Carazo’s experiments dealt with ultimate causation and why?

- The first experiment by Carazo dealt with ultimate causation because it wanted to know if male beetles were choosy in regards to their mating behavior. To maximize reproduction success male beetles should direct their mating attempts towards “better” (mature and virgin females) to increase their probability of getting genes into the future, which was found to be the case. More mean time was spent with these superior females – supporting their hypothesis.

c. What is a proximate explanation for a behavior?

- A proximate explanation for a behavior is the “what/or how” of how a behavior occurs and

can deal with the mechanical or developmental aspects that allow a behavior to occur; emphasis on how the process operates in an individual.

- Proximate explanations deal with how a behavior occurs and what biological mechanisms cause/allow it to happen.

d. Which of Carazo’s experiments dealt with proximate causation and why?

- The second experiment dealt with proximate causation, because after showing that male beetles do mate to maximize fitness, the researchers were interested in determining how this distinction between poor and good potential mates was made. Carazo believed the proximate cause to be chemical which was tested by having mature and immature and virgin and mated beetles crawl around on filter paper and then presenting these papers to the male and measuring time spent and contacts with each. Male beetles spent more time with the papers from the superior mates, supporting the hypothesis that the signal they’re responding to is chemical, instead of dependent on other senses, as the females weren’t present.

SECTION II. You must answer this question (Question C).

C. This is figure 3.15 from your text. Please answer the following questions:

a. Did this experiment test an ultimate hypothesis for behavior, or a proximate hypothesis? Why?

- Because this particular experiment was examining the expression of the hormone testosterone as an explanation for differences in male parental care, they are testing a proximate hypothesis – looking at “how” a behavior gets displayed, the mechanisms behind it, rather than “why.”

b. State the hypothesis that was tested.

- Expression of testosterone regulates or is related to male parental care behavior in gerbils.

- The hypothesis tested was that the amount of testosterone a male Mongolian gerbil has is related to the amount of male parental care.

c. State a prediction that would result in this experimental design.

- Castrated Mongolian gerbil males unable to produce testosterone will spend less/more time with pups than non-castrated males.

- Castrated male gerbils will spend more time with pups than will “sham” castrated males.

- A prediction would be that castrated males – who produce less testosterone – would spend greater time and male parental care than the sham control.

d. What is a sham treatment and why is it important?

- A sham treatment is a control treatment where they operate but do not remove the variable in questions -> testosterone production. This allows the authors to conclude that the results they are getting are from the manipulated variable and not the operation.

- The “sham” treatment acts as a control to show that the effects of the operation itself is not what is resulting in the difference of behaviors between castrated and non-castrated males, but rather the difference in testosterone levels.

- The sham treatment – a similar operation but not actual castration – controls for the impacts of handling by humans and the operating procedure itself. This means that any observed differences in parental care time can be attributed to differences in testosterone levels and the castration instead of having an operation performed.

e. What does the Y axis in this figure have to do with our ethogram project?

- “Spending time with pups” is a behavior that the authors would have had to clearly define before conducting this experiment. Once defined, the authors are basically doing a time budget on this behavior, which is very similar to what we are doing in our ethogram project.

- These researchers may have created a behavioral catalog in order to find behaviors they define as “male parental care” and found that time spent with pups is an expression of this. Thus, they then examine how much time is spent involved in this behavior vs. not to look for increases or decreases in male parental care.

- The y-axis, mean minutes spent with pups, deals with our ethogram project because it is a discrete behavior that had to be observed and recorded objectively as part of a behavior catalog before it could be used as a means of comparing behavioral differences in the 2 groups. Our behavioral catalog will ultimately allow us to do something similar and test a hypothesis in our study animal.

Section II. Answer TWO out of the THREE questions in this section.

D. Above is Figure 2.27 from your text. Answer the following questions in reference to this figure:

a. What do we call this kind of analysis?

- Comparative. The same traits are being compared in multiple species.

- Phylogenetic.

b. What does it tell us about arboreal and nocturnal behavior in these species?

- From diagram B it at first looks like the co-existence of nocturnal and arboreal behavior is adaptive since it is so commonly expressed as is the co-existence of terrestrial and diurnal behavior but the phylogenetic tree based on molecular analysis shows that the co-existence of these traits more likely results from shared ancestry than through convergent evolution.

c. Is this figure representing ultimate or proximate explanations for behavior? Why?

- It represents an ultimate explanation for behavior because it seeks to answer why simultaneous expression of two traits has developed similarly across species.

- Ultimate because it examines the development of the trait over evolutionary time, looking at the pattern of expression of the trait across related and unrelated species.

E. Above is figure 3.9 from your text. You may be asked to circle some part of the diagram that is relevant to what we have learned recently. Circle only one sub-unit of this diagram, i.e., a word(s), an oval, an arrow.

a. What is the concept of umwelt?

- Umwelt is how an individual perceives the world around them and in turn affects how that individual interacts with the world.

b. Circle and label one part of the diagram that is most responsible for an animal’s umwelt. Why did you circle that part?

- I circled sensory systems because it is through the sensory systems that external stimuli are collected, and sensory systems are structurally different from species to species leading to (for example) varied acuteness to sound or smell or the ability to see different wavelengths of light

c. Circle and label one part of the diagram that might best serve the function of “Pacemaker” with regard to biological clock functions.

- Pacemaker = Central nervous System

d. Circle and label one part of the diagram that would correspond to a zeitgeber for a biological clock.

- zeitgerber = Input

e. Why is there an arrow from Behavior to Hormones?

- Behavior can affect hormones just as hormones can affect behavior. For instance, winning a fight could increase testosterone levels. [This is an example of a positive feedback loop]

G. Below is Figure 4.8 from your text. Answer the following questions in reference to this figure:

a. What is a knockout technique?

- A knockout technique refers to the process of “knocking out” or deactivating the expression of a particular gene to determine if that gene is responsible for a certain trait.

b. Why is it is a good technique with which to study the genetic basis of behavior?

- It is a good technique to study the genetic basis of behavior because it results in risky predictions and falsifiable hypotheses. Either the knockout will have the expected behavioral impact or not, and this falsifiability is what makes for true science (according to Popper).

- A knockout technique is a good technique to study the genetic basis of behavior because it allows one to examine the effect of a particular gene on the expression of a trait by comparing organisms [that] express it to those in which it has been “knocked out.” If, for instance, a particular behavior is no longer expressed or expressed at lower levels in the experimental group with a knockout technique, this suggests a strong genetic basis to the behavior.

c. State a hypothesis and prediction that would lead to this use of the knockout technique.

- Hypothesis: The ability for a bird to learn a song from an adult tutor has a genetic basis because the FOXP2 gene codes for the ability to learn a song and repeat it. Prediction: If the FOXP2 gene is knocked out, shFOXP2 birds, even when paired with adult tutors, will have lower similarity scores to the songs of their tutors then will birds whose FOXP2 genes were not knocked out.

- A possible hypothesis is that the FOXP2 gene is responsible for song learning in these birds. A prediction that would lead to this use of the knockout technique from this hypothesis would be that birds that had FOXP2 knocked out (shFOXP2) would have lower song similarity to their tutors than birds in the 2 control groups. The controls exist to account for other variables so that observed differences in song similarity score are explained by the knockout alone.

- Hypothesis: The song-learning capability of birds has a genetic basis (or more specifically: expression of the FOXP2 gene is related to song learning capabilities of birds). Prediction: Birds in which the FOXP2 gene has been knocked out will have lower similarity scores to the songs of their paired tutors than birds in which the FOXP2 gene is expressed normally.