Biology 211 Final Exam Review Questions

Biology 211 – Final Exam Review Questions Go over this before the review session (date to be determined)

1. If differences in phenotype are observed in populations of a species occurring in different habitats, how can you determine if the cause is phenotypic plasticity or genetic differences (other than by actually examining the genotypes through molecular studies)?

2. In their reproductive biology, flowering plants have a diversity of mechanisms that may promote cross fertilization, self pollination, or even asexual reproduction.

a) Describe three mechanisms occurring in flowering plants that promote cross fertilization. b) Describe two mechanisms occurring in flowering plants that promote self pollination. c) Describe two mechanisms occurring in flowering plants that result in asexual reproduction.

3. In what kinds of situations will self pollination be advantageous in spite of the genetic disadvantages? Described what those genetic disadvantages are.

4. What is the genetic differences between self pollination, cross pollination between flowers on the same plant, and cross pollination between flowers on different plants. Which of these results in cross fertilization?

5. Studies of chromosome number have attracted a good deal of attention in plant taxonomy. Describe an example that shows how this information can help identify the evolutionary history in a group, including hypothesizing the ancestral character state.

6. What is a polyploid pillar complex and what are the difficulties in applying the Biological Species Concept, the Phenetic Species Concept, and the Evolutionary Species Concept to such a group? Your answer should contain definitions of these three species concepts and the mechanisms by which polyploidy occurs in a complex of this kind.

7. What are the different factors that might cause reproductive isolation during allopatric speciation and sympatric speciation?

Allopatric speciation — Sympatric speciation —

8. Suppose that you are studying two populations of a species that differ in a number of morphological characters and that the habitats in which they occur are different. How would you determine the causes for those morphological differences? Explain the procedures you would use and the kinds of results you would obtain, depending on the causes of the differences. 9. What mechanical processes (i.e., not physiological processes like incompatibility mechanisms) promote cross-fertilization in flowering plants?

10. What are the causes of gene flow and factors that limit gene flow within a large population?

11. When two closely related flowering plant species are at least partially sympatric (their ranges overlap), individuals may interbreed unless there are reproductive isolating mechanisms. List and describe five different kinds of reproductive isolating mechanisms that occur in flowering plants.

12. Incomplete reproductive isolation between sympatric species in many groups of flowering plants is common. What are the different kinds of results that occur in such situations?

13. Why do hybrids create difficulties in reconstructing phylogenies? Illustrate this with an example that shows the distribution of apomorphies.

14. How can chloroplast DNA help resolve questions of ancestry where hybridization is believed to have occurred?

15. For each of the following species concepts, provide the criterion for species definition and then the way in which the concept would be used in practice to actually determine how species are to be recognized in a genus being studied.

Species Concept 16. Criterion for species definition Practical application criterion

Biological

Phenetic

Evolutionary

17. In a phylogenetic sense, when does a species originate and when does it end? Your answer should cover the various issues related to this question.

18. Why do we often have to use morphological or genetic distinctness, along with geographic distribution, as evidence for individual species even when we are using the Biological Species Concept? 19. There are many differences between the recently proposed classification systems of Cronquist (which we focused on in this course), and other taxonomists such as Takhtajan, Thorne, and Dahlgren, particularly in the placement of certain problematic families. In one classification system a particular family may be placed together with one group of families, while in another classification system that family may be placed with a different group of families.

a) Why do taxonomic opinions differ, even when the taxonomists have the same general information to work with? b) Describe what you would do if you were trying to decide whether a family is more closely related to one group of families or another. Include a description of the kind of information you would like to have and the manner in which you would evaluate that information. State what your criteria for determining relationship would be.

20. Among flowering plants, there are two major types of vascular tissue arrangement within the stem: vascular bundles in a ring and vascular bundles appearing to be scattered through the stem. The other non-flowering seed plants all have vascular bundles arranged in a ring. What does this character tell us about the phylogeny of flowering plants? What conclusion about the classification of flowering plants does it suggest?