answering the questions for each case.
Microsoft Word - Chapter 24 Case Study- (201901) Chapter 24 Case Study The Origin of Species Professor: Mark D. Graves Updated 201901 The following case study will be based on this article: https://www.pnas.org/content/100/11/6598 Sympatric speciation as a consequence of male pregnancy in seahorses Adam G. Jones†‡, Glenn I. Moore§, Charlotta Kvarnemo¶, DeEtte Walker_, and John C. Avise_ †School of Biology, 310 Ferst Drive, Georgia Institute of Technology, Atlanta, GA 30332; §Department of Zoology, University of Western Australia, Nedlands, Western Australia 6009, Australia; ¶Department of Zoology, Stockholm University, S‐106 91 Stockholm, Sweden; and _Department of Genetics, University of Georgia, Athens, GA 30602 ABSTRACT The phenomenon of male pregnancy in the family Syngnathidae (seahorses, pipefishes, and sea dragons) undeniably has sculpted the course of behavioral evolution in these fishes. Here we explore another potentially important but previously unrecognized consequence of male pregnancy: a predisposition for sympatric speciation. We present microsatellite data on genetic parentage that show that seahorses mate size-assortatively in nature. We then develop a quantitative genetic model based on these empirical findings to demonstrate that sympatric speciation indeed can occur under this mating regime in response to weak disruptive selection on body size. We also evaluate phylogenetic evidence bearing on sympatric speciation by asking whether tiny seahorse species are sister taxa to large sympatric relatives. Overall, our results indicate that sympatric speciation is a plausible mechanism for the diversification of seahorses, and that assortative mating (in this case as a result of male parental care) may warrant broader attention in the speciation process for some other taxonomic groups as well. Question 1: What is the common name and scientific name of an organism in this study? ______________ (common name) ___________________(scientific name) Question 2: What does ‘assortative mating’ mean? ____________________________________ Question 3: The authors argue that the females chose males based on ____________________ Question 4: What is the definition of sympatric speciation? ______________________________________________________________________________ Question 5: What does the term ‘sister taxa’ mean in this article?______________ Question 6: The authors mention two mechanisms that allow speciation when organisms are NOT geographically isolated. In the first paragraph of the article (go to the link), what were these mechanisms? 1) _______________________ and 2) _________________________________ Question 7: Regarding these two mechanisms that drive speciation, what type of selection would drive speciation? __________________________________. Question 8: In Figure 1 of the paper, what does their data suggest (explain their line)? __________________________________________________________________________ Question 9: What does “G” mean in Figure 2? ____________________________ Question 10: What happens to the population of seahorses after 100 generations of their simulation? ________________________________________________________________________________ Question 11: The author states that their molecular phylogeny results have TWO candidate cases of sympatric speciation. Circle them on Figure 3 (below) and explain WHY you think the author believes these are cases of sympatric speciation (defining the term sympatric speciation will be helpful in your argument). Question 12: Why do you think the author felt it was important to include figure 4 in their paper? Figures Question 1 What is the common name and scientific name of an organism in this study: common name: Question 2 What does assortative mating mean: Question 3 The authors argue that the females chose males based on: Question 4 What is the definition of sympatric speciation: Question 5 What does the term sister taxa mean in this article: 1: and 2: drive speciation: Question 9 What does G mean in Figure 2: 1_2: 2: Question 12 Why do you think the author felt it was important to include figure 4 in their paper: 1_3: 2_2: Chapter 22 Case Study Descent with modifications: A Darwinian View of Life Professor: Mark D. Graves Updated 201901 The following case study will be based on this article: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5182440/ ABSTRACT Increases in anthropogenic movement have led to a rise in pathogen introductions and the emergence of infectious diseases in naive host communities worldwide. We combined empirical data and mathematical models to examine changes in disease dynamics in little brown bat (Myotis lucifugus) populations following the introduction of the emerging fungal pathogen Pseudogymnoascus destructans, which causes the disease white-nose syndrome. We found that infection intensity was much lower in persisting populations than in declining populations where the fungus has recently invaded. Fitted models indicate that this is most consistent with a reduction in the growth rate of the pathogen when fungal loads become high. The data are inconsistent with the evolution of tolerance or an overall reduced pathogen growth rate that might be caused by environmental factors. The existence of resistance in some persisting populations of little brown bats offers a glimmer of hope that a precipitously declining species will persist in the face of this deadly pathogen. Question 1: What is the common name and scientific name of the bat being studied? ______________ (common name)___________________(scientific name) Question 2: What type of pathogen is being discussed here (e.g. Bacterial, Fungal, Helminth)? _____ Question 3: What disease is caused by this pathogen? _________________ Question 4: What are the signs and symptoms of this disease? Signs: ______________________Symptoms: _______________________ Question 5: Where would the pathogen and host come into contact with one another? _________ Question 6: How could the pathogen spread to other bat colonies? ____________ Question 7: Are you surprised by this statement “The existence of resistance in some persisting populations of little brown bats offers a glimmer of hope that a precipitously declining species will persist in the face of this deadly pathogen”? _______ (yes or no) Explain your answer to #7: _______________________________________________________________________________ ________________________________________________________________________________ Use the graph below to answer questions 8 – 10 Question 8: What does the red box in the figure below represent? Be sure to define any abbreviations. ______________________________ Question 9: What does epidemic and persisting mean in this graph? ______________________________________________________________________________ Question 10: Why do you think the red lines (groups) have such a dramatic decrease in the bat counts but the blue lines (groups) do not? ____________________________________________ ______________________________________________________________________________