Exams

Watch this TED talk. Seriously. Getting into the right mindset before an exam or quiz or class or whatever can make a HUGE difference. []

=Fourth & Final exam (Dec 12 @ 10:10AM - 1PM)=

Study guide:
Nutrient Cycling: What’s a flux? A store? What is the primary difference between energy and nutrient flows? What do we track or follow in a nutrient cycle? What types of nutrients do we care about? Why? How does Nitrogen cycle and move through an ecosystem? What controls the rate of N cycling? The size of the pools? How does the N cycle relate to the cycling of other nutrients? How does nutrient cycling link different ecosystems? What does it mean for a nutrient cycle to be “tightly coupled” and what does that mean for nutrient retention in an ecosystem? How does decomposition work into nutrient cycling? What is the role of microbes in nutrient cycling? How about mutualistic symbioses? How does N-cycling work throughout succession? How does P cycling differ from N cycling? From C cycling? Is P or N more important to ecosystem productivity? What are the consequences of excess P and N on ecosystems? What about pumping SO2 and NOx into the atmosphere? How does acid rain affect terrestrial and aquatic ecosystems? Why is limestone important? How does stoicheometry relate to nutrient availability and productivity? To community composition?

Ecosystem Ecology What is production? How does primary production differ from secondary production? How are GPP, NPP, Ra, and Re related? How do we measure each? (Think flux towers, light-dark bottles, etc.) Can NPP or NEP be negative? How does this relate to autotrophy/heterotrophy of the ecosystem? How does this relate to ecosystem footprints? How does production relate to standing biomass? What is the relationship with turnover or residence time? What is residence time and how does it vary between ecosystems (e.g., forests, grasslands, and aquatic ecosystems)? What controls GPP in terrestrial and aquatic ecosystems? How do GPP and NPP vary in space and time? (Think cycles and general patterns of high vs. low.) What is the ultimate source of the energy in top predators? In detritivores/decomposers? How do we define an ecosystem? How are the inputs into an ecosystem related to the outputs? What controls secondary production? How does this differ in different types of ecosystems? How does this relate to the various aspects of trophic efficiency (CE, AE, PE)? What are average TE’s? How does this relate to food chain length? What determines how much NPP ends up in the grazer versus detrital food chain? Be able to draw Sankey diagrams showing energy transfer from one trophic level to another. Also be able to draw Eltonian pyramids for biomass, energy, and numbers of individuals

Bigger picture/connections How do communities and ecosystem processes (e.g., nutrient or energy cycling) change after different sorts of perturbations? Are the effects different at different time scales? Try to connect nutrient cycling to community dynamics (e.g., succession, stability) and to competition. Think about how mutualisms affect ecosystems. Think about nutrient cycling and food chain length. How do functional responses relate to “dead zones” in places like fresh water lakes or the Gulf of Mexico? How does nutrient cycling influence primary and secondary production, or trophic transfer efficiency? Why do we see specialized metabolic functions in grazers and decomposers much more than in carnivores? How might dominance or keystone status relate to trophic transfer efficiency? Why are there so few large, top predators?

Practice Exam
And the Key

Study guide:
What’s the difference between infection and disease? What impacts can infectious disease have on their host populations? What are //S//, //I//, and //R// in an SIR model? How does //I// change through time for a directly-transmitted infection? How about for //S//? What is R0, what does it tell you, and how does it relate to transmission, host density, and recovery time? What is herd immunity? How does it relate to immunization? What is the difference between density- and frequency-dependent transmission? How is //R0// for disease similar to //R0// we saw in the life history chapter?
 * Disease ecology:**

What is a community? How is one defined? How do communities arise? Is it random or predictable? What is succession? What is primary vs. secondary succession? What drives succession? I.e., what aspects of biology are involved in or necessary for succession to occur? What are early successional species like? How do they differ from late successional species? How do the facilitation, inhibition, and tolerance models of succession work? How are they similar and where/when do they differ? Can you think of examples of each model at work? What is an ecosystem engineer? How do we define food webs? What characteristics of food webs are most important? How do real food webs compare with the theoretical ones? What is missing from most food webs? How does a food web relate to a food chain? How does bottom up vs. top down control of a food chain work? When would you expect one or the other? What determines food chain length? What are trophic cascades? How do they work? What happens when a predator feeds at multiple levels of the food chain? What do they imply about bottom up or top down control of food chains? What features of a food chain would promote trophic cascades? How does the diversity of a community relate to the stability of individual species and to communities? What do we mean by stability? What would one measure? What aspects of community disturbance do we measure? What are examples of disturbance? What features of communities favor stability in the face of disturbance? Why? I.e., how is stability a consequence of these features? What’s a keystone species? A dominant? How would you recognize them?
 * Community Dynamics**

How do different types of decomposers compete with and/or facilitate each other in the decomposition process? What controls the rate of decomposition? How does decomposition relate to the many other aspects of ecology we’ve discussed (e.g., niches, competition, succession, nutrient cycling, metapopulation dynamics). For instance, I might ask: How does succession apply to the decomposition process? How does diversity and specialization change through time? How are detrital food webs different from other compartments of an ecosystem’s food web?
 * Decomposition:**

**Second exam (Oct 17)**
Practice Exam Key (don't cheat; do the test first!) NOTE: I updated the key at of 9:20PM on 16 October. I had made an error in my math while calculating lambda and r in the question on the life table (page 7) How do the geometric and exponential models differ? What do they assume? Which of these assumptions is relaxed in the logistic model? How do r and lambda relate to each other? How does r relate to dN/dt? How would you estimate these rates? Understand doubling time. What is K? What does K imply about competition? When does dN/dt = 0? Make sure you can graph per-capita and population growth rates against time and N for all of the models
 * Key to exam 2:**
 * Practice Exam:**
 * Study guide: **
 * Population growth:**

What does metapopulation theory tell us, particularly in regard to conservation? What sort of organisms might exist in a metapopulation? How is it similar to or different from island biogeography? When does dN/dt = 0? Make sure you can graph immigration and extinction rates against P and show how the graph will change if you tweak parameters and/or violate assumptions. Understand the assumptions of all of the models!

How is it that organisms with very slow rates of maturity and small reproductive rates can persist in the face of other organisms that reproduce quickly and in great number? What kind of life history would the “perfect” organism have? Why do we never see the “perfect” organism? How do unitary and modular organisms differ? What is senescence? What is iteroparity? Semelparity? What are examples of life history trade-offs? What are life tables? What are they used for? How do you use them? (Make sure you can fill out a life table and make conclusions from it.) What is R0 and how does it relate to r? What is T? Be sure you can read, interpret, and draw survival curves. Can you think of organisms that might illustrate different life histories?
 * Life History:**

Make sure you understand what a fundamental niche and a realized niche are. Can you draw a one- and a two-variable graph showing the extent of a species' niche? Where on the graph is dN/dt > 0, = 0, and < 0? How might competition or predation alter the graph? How do the fundamental and realized niches relate to competition? How does these relate to conditions and resources? How does the logistic model represent competition? What do the parameters mean? How does K relate to b and d? How do individuals compete? How does exploitation differ from interference competition? Do these differ between intra- and interspecific competition? What are the assumptions of the Lotka-Voltera model of competition? What do the parameters mean? How are the α’s like currency conversion rates? What do the isoclines represent? Be able to draw (and distinguish) the isoclines for the 4 general scenarios resulting from the L-V model. What distinguishes them? Where are the equilibriums? Which are stable? Why? Be able to draw general dynamics (vectors and trajectories of the two populations) that result from each scenario.
 * Competition:**

What are the assumptions of the Lotka-Voltera model of predator-prey dynamics? What do the parameters mean? Be able to draw the L-V predator-prey isoclines and modify them with prey carrying capacity, predator self-limitation (e.g., carrying capacity), and refuges from predation. Make sure you know where the lines should be (roughly) and why. Also, be able to draw the general dynamics given a set of isoclines or a description of the system. Which of these features of the L-V models are stabilizing? How are metapopulations relevant to predator-prey dynamics? What are functional responses and how do they arise? What type(s) of organisms would have one or another? What consequence(s) can they have for individual prey or for predator-prey dynamics? How is it that even intense predation might have very little impact on the growth of the prey population?
 * Predation, herbivory, and parasitism:**

**First exam (Sept 12)**

 * Note: you are welcome to bring a calculator, though you probably will not need it. Phones or smart devices are not allowed.**

The key to the first exam. Note that some questions are graded in reference to a previous answer, so there may be no single answer (and thus a blank on the key). You should feel free to come to office hours to ask me questions about the exam or just make sure you understand the concepts on it.

A study guide with some general, but useful advice A practice exam with questions from previous exams or questions I almost used. Note that this is **not** comprehensive and does not necessarily hit on every subject that I will ask about in the real exam. It is meant to give you practice answering the //types// of questions I will ask on an exam. I will post the key on Tuesday.