Exam 2

• What are Tinbergen’s 4 behavioral ecology questions?

  1. How is behavior produced?

  2. How does a behavior develop?

  3. What is the adaptive value of a behavior?

  4. What is the evolutionary history of the behavior?
• What are fixed actions and sign stimulus?

  Fixed actions are the behaviors performed by all members of one sex of one species in a stereotypical pattern triggered by sign stimulus.
• Optimal foraging models predict when a predator will switch from one prey to another. Describe the different reasons why real-world observations of foraging behavior may not match model predictions.

  This model assumes knowledge that animals might not have, it assumes conditions are constant, assumes that we know the costs/benefits of each prey to make the model correct, and assumes decisions only made based on one trade-off.
• What is coevolution?  

  successive, reciprocal evolutionary change in each of two species in response to selection imposed by the other species
• What are the three major consequences of coevolution? Are these consequences likely to be stronger in species with obligate or facultative interactions?

  - Consequences: Morphological relationships, speciation, geographical patterns

  - Stronger in obligate symbioses
• What is the definition of commensalism?

  one species benefits the other is neutral
• What are the 5 primary adaptations of parasites to benefit their fitness?

  1. Sensory strategies

  2. Synchronization of reproductive cycles to that of host

  3. Alteration of host behavior to increase the chance of transference

  4. Alteration of host metabolism to increase host life-span

  5. Avoidance of host immune system (molecular mimicry)
• What is a niche?

  Organism’s role and place in the environment.
• What is the difference between a fundamental niche and a realized niche?

  o Fundamental niche: The potential distribution of an organism in the absence of any interspecies interactions.

  o Realized niche: Actual place or role an organism occupies after species interactions occurs.
• Describe Case 1

  Species 1 increases in both yellow and green area but species 2 only increases in yellow since it's on the y-axis. Species 1 increases in green but drives species 2 down to zero. Sp1 stabilizes at K1. This is stable equilibrium because anywhere you start the ball will roll to K1 and Sp1 will always outcompete Sp2.

  
• Describe Case 2

  Sp2 increases in yellow and orange, Sp1 only increases in yellow. Sp2 increases in orange and drives down Sp1. Stable equilibrium Sp2 stabilizes at K2.

  
• Describe Case 3

  Sp1 increases in yellow and green. Sp2 increases in yellow and orange. Stabilizes at intersections = coexistence = stable equilibrium.

  
• Describe Case 4

  Sp1 increases in yellow and green, Sp2 increase in yellow and orange. Stability at either k1 or k2. One species ends up winning. Unstable equilibrium.

  
• Describe competitive exclusion

  when the fundamental niche of species 1 overlaps completely with species 2
• How can you avoid complete competitive exculsion?

  niche breadth – mean value of resource use doesn’t change but variance decreases.

  Changing niche position – variance stays the same but mean value of resource use changes in one or both species.
• What is character displacement?

  evolutionary consequences of competitive exclusion divergence in critical niche dimensions.
• What criteria must be met to infer that character displacement is occurring?

  o Observed Pattern couldn’t occur by chance

  o Phenotypic differences must have genetic basis

  o Trait differences must result from actual evolutionary changes

  o Morphological differences must reflect differences in resource use.
• Define facilitation.

  Enhancement of the response of something due to stimulus
• Explain the graph

  Top: arrows represent predator and prey abundance less prey = less predators more prey = more predators.

  Bottom: vectors are combined they show the direction of oscillation. So predators increase after prey because predators rely on the prey. This leads to oscillating abundances with a temporal offset between prey and predators.

  
• What evidence would you need to prove that a predator exhibits a Type 2 Functional Response as a result of an increase in prey density?

  Type 2 shows a limit in intake rate under assumption consumer is limited by its capacity to process food.

  Evidence to prove this would be a curvilinear increase in prey density showing that predator isn’t hunting and its slow because predator doesn’t hunt often.
• Red Queen Hypothesis

  Organisms have to constantly evolve to maintain fitness in the face of environmental change and other organisms.
• Review the prey defense hierarchy: Avoid (Hide), Escape, Defend, Tolerate. Give real-world examples for each of the defense strategies.

  Avoid – stick bug blends in with environment on trees to avoid detection

  Escape – Gazelles are such agile and speedy bitches

  Defend – Giraffes can stomp on lions and break their skulls

  Tolerate – Tree can handle a Giraffe eating their leaves
• Define Batesian and Mϋllerian mimicry

  Batesian Mimicry: organisms that are not noxious will copy the designs of noxious organisms

  Mϋllerian mimicry: noxious species look similar
• What is the Logistic equation

  (dN/dt) = rN(K-N/K)