Lecture 21-22: Population Growth & Regulation Flashcards
N sub t symbolizes what?
What is N sub t+1?
Population size at time t.
Population size in the next generation.
B symbolizes what?
Births
D symbolizes what?
Deaths
I symbolizes what?
Immigrants
E symbolizes what?
Emmigrants
What happens to a population when r>0?
Population grows
What happens to a population when r=0?
Population is stable
What happens to a population when r<0?
Population declines
What is the exponential population growth equation or “rate equation”?
dN/dt = rN
What is the equation used to project population size?
The “state equation”.
What does lambda stand for?
The ratio of population
Change in population size equation
Geometric population growth
geometric population growth: (population size now)/(population size last year
What equation would we use for these questions:
1) Assume that our population is “closed” – no immigrants or emigrants
2) Assume that population growth is continuous (allows modeling with continuous differential equation)
3) instantaneous birth & death rates (b, d; # births or deaths/individual/ time)
Calculate 𝜆 from population sizes at two time points:
The ‘Ö’ü (Psittirostra psittacea) is a critically endangered Hawaiian honeycreeper. The last 8(!) individuals were
brought into captivity in 2003. By 2015, the captive breeding population had grown to 116 birds.
Exponential growth VS. Geometric growth
Population doubling time: Exponential population growth
Population doubling time: Geometric population growth
Model Assumptions:
