Study Guide for Chapter 5
Q1: Most behavioral traits are complexly determined, rather than due to a single gene. Often it is of interest to inquire about the degree to which a trait is influenced (if any) by genes. This can be done using ________ ______ analyses.
A1 Quantitative genetic analyses (e.g., adoption studies, twin studies, family studies)
Q2: The astonishing differences among dog breeds may indicate that they are many different species. Is this so? Explain.
A2: No, they are all members of the same species. Molecular genetic research suggests that dogs, which originated from wolves about 30,000 years ago as they were domesticated, may have enriched their supply of genetic variability by repeated intercrossing with wolves
Q3: Do dog breeds differ in behavior? Is so, are these differences at least partly genetically based?
A3: Although physical differences between breeds are most obvious, dogs have been bred for centuries as much for their behavior as for their looks. In 1576, the earliest English-language book on dogs classified breeds primarily on the basis of behavior.
Behavioral classification of dogs continues today. Sheepdogs herd, retrievers retrieve, trackers track, pointers point, and guard dogs guard with minimal training. Breeds also differ strikingly in trainability and in temperamental traits such as emotionality, activity, and aggressiveness, although there is also substantial variation in these traits within each breed
Q4: The DeFries selective breeding program to develop lines of mice which differed in Open-Field activity is often cited as an example of artificial selection (in the lab, not by nature). About how many times more active are the High active lines now, than the Low active lines?
A4: , a 30-fold average difference in activity has been achieved. Mice from the high active line now boldly run the equivalent total distance of the length of a football field during the six-minute test period, whereas the low-active mice...