Name______
Take home is due on Tuesday. Please place a hardcopy of the exam under my office door. If you place it in the mailbox outside my door, please place your exam in a sealed envelope to discourage others from looking at your exam.
1. Classification: application. Use the tree below in answering parts, b - d. 12 pts.
a. Define synapomorphy
b. Why are the two extant species on the left considered part of an out group branch?
c. List the traits (of those shown on the diagram) that could be considered synapomorphies. Defend your answers for one of the traits you listed.
d. List the traits that could not be considered synapomorphies. Defend your answers for two of the traits you listed.
2. Coevolution: extension and application. 15 pts.
a. Use the notes on mutualism to answer the following question. Give two examples of relationships the indicate mutualism evolved from parasitism.
b. Read the overview and history of the hygiene hypothesis at this URL.
As stated in the reference, nematodes and other worms are now being used experimentally to treat autoimmune diseases now on the rise worldwide. Patients are infected with worms and in the case of about five auto immune disorders, these infections cause patients to be asymptomatic or lesson symptoms of the auto immune disease significantly. Most of the worms used, we suspect, have been with humans as long as there have been humans on the planet, and in most cases themselves cause very few symptoms. Most of us are probably carrying a nematode or tapeworm or two with no ill effects. In fact, symptoms only occur in nature when individuals find themselves in situations where they are infected with several dozen or more worms.
Compare what the worms, in what is termed “helminth therapy”, may be doing to the human immune system to how Wolbachia regulates the wasp immune system. Is there evidence then thathelminthes and we are in a co-evolutionary, possibly mutualistic, relationship?
Species and punctuated equilibrium. Examine the material on species and punctuated equilibrium. 23 points
3. You come across a species of plant that is only found in two small areas of the Mohave Desert. The plant spreads vegetatively with new plants developing along runners sent out by the parent plant. Flowers have never been seen. Which definition of species, biological, ecological or phenetic, can best be applied to this plant? Defend your answer, indicating why this plant can and cannot fit each definition.
b. Devise a table to compare and contrast allopatric and sympatric speciation. Why do you suppose sympatric speciation has only been documented rarely?
4. On punctuated equilibrium. a. How could you determine if a phylogeny appears to evolve in a punctuated equilibrium or gradual manner?
b. What do we mean when we say that punctuated equilibrium theory predicts species selection?
c. What is the potential role of genetic drift in obtaining a punctuated equilibrium pattern of speciation with time?
d. What mode of speciation is the punctuated equilibrium model based upon?