# BIOL 290 Lecture Notes - Lecture 13: Sockeye Salmon, Fish Migration

41 views2 pages Geometric Growth
Tuesday, November 13, 2018
5:53 PM
Lambda ( λ)
Estimated growth rate
Finite rate of increase


N(t+1)= population size one year after N(t); one unit of time after N(t)
N(t)= population size at year t
N(0)= initial population size
You can use estimate of lambda to make a mathematical prediction about how large the
waterhemp population will be in future years
o   λN(t)
Geometric Population Growth
λ will be multiplied in each timestep to get an estimated population size in as
many timesteps in the future we want
Examples:
o   
o          λ^2N(0)
o λ^t
General formula
Population changes in successive time steps by a constant ratio
The geometric model works when populations are not limited in their growth; they
continue increasing at the same rate each unit of time
This model assumes that there is only one discrete reproduction event per unit of
time for individuals (annual plants [waterhemp], mating events in some mammals)
Ex: N(0)= 10
λ= 1.35
What is the population size at year 10?
N(10)= N(0)x λ^t

= 201 plants
Who does the geometric population growth model
apply to?
Unlock document

This preview shows half of the first page of the document.
Unlock all 2 pages and 3 million more documents.