Exam 2 Flashcards
Theta
Discrete time (birth pulse rates) algebra
r
Continuous time
Calculus
as long as r is constant over a finite time interval
theta = e^r
k
carrying capacity, the density of the population that the environment can maintain
Notable assumptions of the logistic model
Birth and death rates change linearly with population size (or density)
Average rate of growth
the geometric mean of the geometric process of population growth
n1,t+1
n1,t+1 = m1P0n1,t + m2P0n2,t + m3P0n3,t
Stage-based matrix model
f = fertility p = probability of surviving from year t until year t+1 and remaining in stage i in a stage-based model G = probability of growing and surviving to stage i+1 during t to t+1
sensitivities
The effect of unit changes in the demographic parameters on long-term population growth rate, theta
sensitivities example
1 egg increase in mean clutch size
Elasticities
the effect of relative changes in demographic parameters on long-term population growth rate, theta
elasticity example
10% increase in mean clutch size
Life history components
- Developmental time to first reproduction
- Parity
- Number and size of offspring
- ageing (or senescence)
r-species
have supposedly been selected for their ability to colonize and reproduce rapidly
k-species
have supposedly been selected for their ability to contribute to N when the population is near K and resources are poor
Why is the r-k model no longer valid
Because many descriptors of it are not accurate. Such as climate, mortality, survivorship, N, Dispersal ability, State of ecological succession
Slow species
Low reproduction
Delayed maturity
High survival
Long generation time
Fast species
High reproduction
Early maturity
Low survival
Short generation time
