University of California San Diego Several Sets of Preliminary Knowledge Paper
Please read the articles attached and answer these questions
Callaway (2015) Discussion:
- What prior knowledge (preliminary research findings) spurred the principal investigators (Bhullar and colleagues) to do this experimental study with the jaw development of chicken embryos?
- What did Bhullar et al. do in their experiment with chickens, and what did they find?
- What is the principal implication of the experiment’s results?
- What future research directions by the principal investigators of this study might be possible based on their findings?
- What future research directions by other scientists might be possible based on this study
- Singer (2015) Discussion:
- What is the basic premise behind the “hopeful monsters” hypothesis?
- What were the principal findings of the research on the immediate ancestors of extant birds by Brusatte?
- What were the principal findings of the research on body size evolution in dinosaurs by Benton and colleagues?
- What role did miniaturization play in the evolution of birds?
General Discussion Questions (for submission):
- Paedomorphism is often characterized as the retainment of juvenile characteristics in adults. For example, some salamanders such as the Mexican axolotl possess gills as adults, whereas gills are lost during the transition from larvae to adults in other amphibians. How might paedomorphism have played a role in the evolution of birds?
- Bhullar and his colleagues did not hatch the modified chickens for “ethical reasons” (Singer article) and did not write that in their approved research protocol (Callaway article). Do you think that arresting the development right before hatching was sufficient for the team to achieve their research goals, or might they be missing something by not bringing the modified chicks to term?
- Do the independent research studies of Brusatte and Bhullar (described in the Callaway and Singer articles) support or refute the “hopeful monsters” hypothesis that evolution occurs in leaps and bounds? In what way(s)?
- Do you think that the findings from this line of research as described in the two articles indicate that birds are more closely related (in an evolutionary sense) to dinosaurs or crocodilians or lizards? Please explain.
- How do you imagine that the evolutionary process of natural selection may have operated to cause the separation of the two different lines of jaw development of birds versus other reptiles and mammals? (NOTE: This question is not answered explicitly in either paper that you read. Try to think of your own answer.)
