BI 212 Midterm
skiser/gbaker
Bi 212 Midterm Essay Questions 2008
I will ask one of these questions on your midterm. You must write your answer while in class and you may not use prepared notes. You can write your essay on one of the lab computers, long-hand on the test itself, or if you bring lined paper, you may write it on that and attach it to your exam.
I am giving you key things to remember to address in your essay. You will need to make sure to connect these items as well as writing an essay that fills in the necessary information. As the year progresses, I will give you fewer and fewer of these “key” items. You will be expected to be able to construct coherent essays much like these in your upper division classes.
I will not grade any early essay attempts and will refrain from directly answering questions about the essays. Of course, I will help you study, and your studying should help you answer these questions.
Full credit answers will be written in an essay format, with proper paragraphs. Spelling and grammar will count as well. Correct biological content will also be graded.
Remember: This is an essay. Identify a theme and fully cover it. It will take more than two paragraphs to do this adequately.
Topic 1: Organism responses.
Organisms are not static; they are constantly adjusting to changes in internal and external environments. We studied two distinctive ways that animals and plants respond to change: feedback loops and signal conductance pathways.
Write an essay comparing and contrasting feedback loops and signal conductance pathways. Make sure to cover in your essay:
- Descriptions of feedback loops and signal conductance pathways.
- Examples of organisms that use each.
- Comparisons (similarities) between the two and how the organism responds to change.
- Contrasts (differences) between the two. Be specific!
- Evolutionary advantages to each, tied to the particular type of organism in which the loop/pathway is found.
Topic 2: Plant alternation of generation lifecycles
Plants all have the same general life cycle but the dominant stage of the life cycle differs among plant phyla.
Compare and contrast two phyla where dominant stages of the life cycle differ. In your essay:
- Draw and describe the generic plant life cycle (include all structures and processes)
- State the two plants groups you have chosen to use for comparison
- Compare and contrast their life cycles (you may use contrasting diagrams)
- Identify key points in the plant life cycle that may be vulnerable to life on land
- Describe adaptations that developed that may reduce that vulnerability
- State which dominant stage was ancestral and propose reasons for the shift in dominance
Topic 3: Animal evolution of multicellularity
Unlike plants, the common ancestor to the animal clade is not thought to have been multicellular. The evolution of multicelllularity appears to be key to the evolution of the animal clade.
Write an essay that addresses the evolution of multicellularity in the animal clade. Make sure to address:
- Name the most recent common ancestor to the animal clade and the earliest branch of the animal clade.
- Discuss similarities and differences between these two organisms.
- Describe the molecular evidence supporting the most recent common ancestor to the animal clade and its placement so close to the animal tree.
- Describe at least two other derived traits in the animal clade that occurred after the evolution of multicellularity, and the selective advantages that would select for these derived traits.