PCE - 4

Question 1

what is an inflection point?

Answer 1

where the population goes from exponentially increasing to exponentially decreasing

Question 2

what is happening to human population growth?

Answer 2

growing at a greater than exponential rate

Question 3

what limits population growth for interspecific and intraspecific competition?

Answer 3

intra - negative feedback

inter - competition of resources

Question 4

what is the competition exclusion principle by Gause?

Answer 4

• no two species can share the same resource
• no two species can occupy the same niche
• If they have identical needs they cannot coexist - one outcompetes the other

Question 5

what are the 3 assumptions of the logistic model?

Answer 5

1. Density dependence is linear
2. Population approaches the carrying capacity smoothly
   - But population may overshoot the carrying capacity because there can be a time delay before the death rate increases or the birth rate drops
   - This can lead to oscillations around K
3. K is constant
   - But it may not be…. year to year variation

Question 6

why is it misleading to think selection is acting on r and K?

Answer 6

r and K are population-level parameters which have no
straight forward mapping to the individual-level parameters on which selection actually acts - selection only acts on individuals

Question 7

what are traits associated with high density selection?

Answer 7

• Large, few offspring (TRADE-OFF)
• Delayed reproduction
• Large size
• Long lived

Question 8

what are traits associated with low density selection?

Answer 8

• Many small offspring (TRADE-OFF)
• Early reproduction
• Small, Short lived

Question 9

describe a fundamental niche

Answer 9

is the entire set of conditions under which an animal (population, species) can survive and reproduce itself.

• Intrinsic requirements of a species on its own
• Physiological and ecological limits: Abiotic/Weather
• Biotic limits: Food/Habitat Resources

Question 10

describe a realised niche

Answer 10

is the set of conditions actually used by given animal (pop, species), after interactions with other species (predation and especially competition) have been taken into account.

• competitors
• limitations

Question 11

what are the 3 main competition theories?

Answer 11

• Lotka-Volterra Competition
  • Tilman - R* Theory
  • Grime - CSR Theory (Competitive - Stress - Ruderal)

Question 12

whats the difference between the logistic growth equation and the exponential growth equation?

Answer 12

logistic growth = involves negative feedback / density dependence - intraspecific competition

Question 13

what is the logistic growth equation?

Answer 13

dN/dt = rN (1-N/k)

Question 14

what 3 things does density dependence equilibrium generate?

Answer 14

1) Persistence
2) Stability
3) Coexistence of individuals

Question 15

what happens when you divide per capita growth rates for exponential and logistic growth by N?

Answer 15

exponential = r = a horizontal line- per capita growth is constant 
logistic = r - r/K * N - line with a negative slope - density dependence is acting

Question 16

what is added to the equation when interspecific competition is acting?

Answer 16

α N1 N2 - 2 species interacting

Question 17

describe gauses experiment?

Answer 17

He placed Paramecium caudatum and Paramecium aurelia together in a test tube with the same food supply. P. aurelia grew faster than P. caudatum and when grown together, P.aurelia outmultiplied and eliminated P. caudatum

Question 18

what is the equation for competition theory?

Answer 18

population = . exponential - intraspecific . - interspecific
growth rate . growth competition . competition

dN/dt = rN1 - rN2/K - aN1N2

Question 19

how can the equation for competition theory be made into the equation for a line?

Answer 19

N1= K1 - a12N2

intra specific carrying capacity = intercept
inter specific carrying capacity = gradient