Lec 16- How do we model populations? Flashcards
science
representation of an idea
What do birth and immigration do to population:
increase pop
what do death and emmigration do to population:
decrease pop
non-sessile
animals move freely and take advantage of dispersal vectors.
Death
could be from old age, disease, lack of resources, herbivory, predation.
Nt+1
population size in the future (at time + 1)
Nt=
population size at time ‘t’
Nt+1=Nt+B+I-D-E
changes in population size as a function of past population size and the BIDE factors.
Net reporoductive rate (R0)
average number of offspring produced by a female individual in her lifetime
Geometric Rate (/)
the ratio of the population size at two points in time
Generation Time (T)
the average age within a population at which a female gives birth to her offspring. Can be greater than the age of first reproduction, if females reproduces more than once.
Per Capita rate of increase (r):
equal to per capita birth rate minus per capita death rate
2 types of dispersals and examples
Abiotic: wind water
Biotic: birds, insects etc.
Density independence- example
a windstorm can increase the # of deaths independent of population density
density dependence- example
high moose density leads to high tick (parasite) density, which decreases # of births and increases deaths among juveniles.
How do we measure the rates of population change
by using a life and a fecundity schedule
fecundity schedule
a tabulation of birthrates for females of different ages in a population
What are the 4 parameters of population change
-Net reproductive rate
-geometric rate of increase
-generation time
-per capita rate of increase
Net reproductive rate (R0)
average number of offspring produced by a female individual in her lifetime
geometric rate of increase (/)
the ratio of the poppulation size at two points in time
generation time (T)
the average age within a population at which a female can be greater than age of first reproduction, thats if female produces more than once
per capita rate of increase (r)
equal to per capita birth rate minus per capita death rate (b-d)
