Week 13 Activity

Review 2: Community ecology, Quantifying biodiversity, and Patterns of biodiversity Community ecology - competition 1. In the competition model we studied, the dynamics of the two species are given by the followingpair of equations. part A part B 𝑑𝑑 𝑑𝑑 1 = 1 𝑑 1 (1 − ?⏞ 11 𝑑 1 −?⏞ 12 𝑑 2 ) part A part B 𝑑𝑑 𝑑𝑑 2 = 2 𝑑 2 (1 − ?⏞ 22 𝑑 2 −?⏞ 21 𝑑 1 ) a. Using your own words, describe the biological process described by the terms labeled “Part A” in the equations above. (0.25pt) The equations above are used to calculate the population density over time while incorporating interspecific and intraspecific competition. “Part A” is the intraspecific competition effect of species 1 on itself in the first equation and species 2 on itself in the second equation. N represents the population density for the intended species. b. Using your own words, describe the biological process described by the terms labeled “Part B” in the equations above. (0.25pt) “Part B” is the interspecific competition effect between species 1 and 2. The top equation displays the interspecific competition effect of species 2 on species 1 and the second equation displays the competitive effect of species 1 on species 2. 2. Consider a pair of species that interact with each other with the following strengths: 𝑑 1 = 0.25 𝑑 2 = 0.5 ? 11 = 0.008 ? 12 = 0.0015 ? 22 = 0.007 ? 21 = 0.0035 If there were a community in which only Species 1 was present (Species 2 is entirely absent), what would be the population size of Species 1 at equilibrium? Explain your thinking and your calculations. (0.5 pt) For this community species 1 is reaching its carrying capacity and N 2 equals 0 since it is absent. To find the the population size at equilibrium, we set dN/dt = 0 in the equation / 𝑑𝑑 1 = 1 𝑑 1 (1 − ? 11 𝑑 1 −? 12 𝑑 2 ). The equation will now look like this after substituting 0 for dN/dt and N 2 , 0= r 1 N 1 (1-− ? 11 𝑑 1 −0). After distributing the r 1 N 1 and solving for N 1 , we get the final equation of N 1 = 1 / /? 11 = 1/0.008 = 125. Species 1’s population size at equilibrium will be 125. 1

3. Consider a pair of species that interact with each other with the following strengths ( note- these are the same numbers as in question 2. ): 𝑑 1 = 0.25 𝑑 2 = 0.5 ? 11 = 0.008 ? 12 = 0.0015 ? 22 = 0.007 ? 21 = 0.0035 Use the following graphs to draw the isoclines as labelled. On each graph , make sure to • label the X- and Y-intercepts in terms of different ? 𝑑𝑑 parameters (1 pt) • draw vectors (arrows) showing the trajectory of the population in different parts of the graph (1pt) Species 1 and 2 isoclines 2 N1 N2 Species 1 isocline N1 N2 Species 2 isocline 66 7 14 3 12 5 28 6 N1 N2 66 7 14 3 12 5 28 6 Species 1 Species 2

the resource ) and consumer ) as follows: ( ( ( = − = − Where and are the abundance of the resource species and of the consumer species, respectively. • In your own words, describe the biological processes that is represented by the parameters , , , and . (0.5 pt) The biological process that is represented by r is the intrinsic growth rate of the resource being looked at,and a is how quickly the consumer “C” is using and consuming the resource. The parameter e is how efficiently the consumer uses the amount of energy it receives from the resource and parameter m is the amount of energy that is lost due to the consumer species. 6. Consider a Consumer–Resource system whose dynamics are described by the following parameters: 𝑑 = 0.5 𝑑 = 0.2 𝑑 = 0.1 𝑑 = 0.3 Use the following graphs to draw the isoclines as labeled. On each graph , make sure to • label the X- and Y-intercepts in terms of the parameters , or (1 pt) ,, ,, ,, ,, ,, ,, ,, ,, ,, ,, ,, ,, ,, ,, ,, • draw vectors (arrows) showing the trajectory of the population in different parts of the graph (1pt) Resource isocline Consumer isocline Number of Resource individuals Number of Resource individuals Consumer and Resource isoclines 4 Number or Consumer individuals Number or Consumer individuals 1 5 5

Quantifying biodiversity patterns 8. You survey the insect biodiversity of a farm and an adjacent restoration prairie, and you find the following patterns of diversity: • Based on the graph above, would you expect the Shannon diversity to be higher in the farm or in the prairie? Explain your reasoning. (0.5 pt) o The Shannon diversity will be higher in the prairie because even though the farm is more diverse, when you pick up an insect at the farm you can assume that it will be species A. Shannon diversity measures the degree of surprise or uncertainty an environment has when picking up an insect or animal. The prairie has a more even disbursement of insects therefore when picking up an insect there is more uncertainty as to what it will be so the Shannon diversity will be higher for the prairie. • What is the formula for calculating the Shannon diversity? Please provide a verbal description for each term in the formula. (0.5 pt) 5 Number of Resource individuals Number or Consumer individuals 5 1 5 farm prairie A B C D E F A B C D E F 0 5 10 15 20 25 0 5 10 15 20 25 species abundance

10. Reflect back on the various conversations you might have listened to as part of the Weekly Activities during these units: • Hidden Brain episode about the health impacts of spending time in nature • In Defense of Plants episode about the role of predators in maintaining forest health. • Sea Change podcast episode about the Craft of Climate Writing • Sea Change podcast episode about the role of artists in tackling the climate crisis • Conversation with Dr. Camille Dungy , author of the 2023 Book “Soil” • Patagonia Stories episode about Artistic Knowledge • New Yorker Radio Hour episode about the book Braiding Sweetgrass . • The Life Scientific episode about Dr. Anne Magurran’s research on biodiversity trends Did you find any of these episodes especially engaging? What about the conversation did you find most interesting? Did the conversation raise any questions for you that you would like to think about more deeply? (1pt) The two episodes that stood out to me the most were the Hidden Brain and New Yorker Radio Hour episodes. I was fascinated by the Hidden Brain episode because the podcast talked about the benefits of spending time in nature which I believe are true. Spending time in nature is one of the best and peaceful things for me to do. When I am in nature, there is this feeling of connection to the things around me and the universe that takes away all my worry. I hope that more people listen to that podcast and realize the benefits of nature so that they put down technology and experience the natural world. Technology creates such a negative atmosphere for people and mainly for kids that get exposed to that at a young age. Nature is humans' home, it's where we lived and spent all our time and now that idea is lost to most people. The New Yorker Radio Hour episode told the story of native american writer Robin Wall Kimmerer and she is perfect. The way that she lives, is the way that I want to live. Being in and making connections in nature are what brings true peace to me. If more people felt that way and spent time in nature rather than in the online world, I believe that this world would be a much better place. Listening to Robin's story and excitement about the little chickadees trusting her and eating out of her hand brought peace to me. That excitement and appreciation of nature is what I hope more people discover in life and I am scared that people may divert away from that as technology advances. I plan to incorporate nature throughout my life and my family's life for generations to come and I hope other family’s do as well. 7