These relate to the Lotka-Volterra equations wediscussed for competition and for predation. You may have to useweb resources for some questions.
For two competing species, use what you know aboutLotka-Volterra models to sketch and describe the outcomes for eachof the following scenarios:
What would be the ultimate outcome for both competitorsin each of the following sets of conditions? (15 pointstotal).
12. K1 = 200, K2 = 100, alpha = 1.5, beta =2
Species 1 will win the competition.
13. K1 = 100, K2 = 200, alpha = 1.5, beta =2
Species 2 will win the competition.
14. K1 = 200, K2 = 100, alpha = 2.5, beta =1.5
Both species have greater competition with each other,so there is UNSTABLE coexistence.
Remember, I used β (beta) but your book uses alpha (α1,2and α2,1). It’s just two ways of saying the samething.
Let’s take it up a notch. Consider the followingscenario: For many years, the population size of Species 1 hasconsistently hovered around 100 individuals/km2 while Species 2’spopulation size has been approximately 50 individuals. Species 1uses resources at one-quarter the rate of Species 2. Use theinformation to answer the following questions. You’ll need yourcritical thinking skills!
Given the information available, sketch theLotka-Volterra isocline diagram that best represents the scenarioabove. Don’t forget to label your graph. Are the populations ofeach species likely to be stable or unstable? (5points)
Now imagine a case where the values above are thecarrying capacities, not the population sizes. For simplicity’ssake, assume that resource use is the only factor that determinescompetition coefficients (alpha and beta). Sketch the isoclinediagram that describes this new scenario. Which species should win?(5 points)
BONUS (3 points) What would be the population sizes ofeach species in the absence of their competitor? In other words, ifI removed individuals of Species 1, how many individuals of Species2 could there be? Likewise, if I removed individuals of Species 2,How would Species 1’s population grow? (Hint: it might be helpfulto first consider the effect of removing a singleindividual).
Explain how the two figures below relate to one anotherin terms of predator-prey relationships? Label the axis and put inany missing directional arrows (5 points)
