Transcript snc2l u4l2 populations moose case study

Populations
Lesson 2
Population
- all of the members of a species living in
the same ecosystem or habitat.
Population growth
patterns
 Changes in population size occur when
individuals are added to or removed from a
population.
 Natality (birthrate) and Immigration
(movement into an area) increase a
population.
 Mortality (death rate) and emigration
(movement out of an area) decrease a
population.
Population growth
patterns
 These four factors interact to determine
population size
 Population growth = births + immigration
– deaths – emigration
Open and Closed
Populations
 Open populations = populations where
births, immigration, death and emigration
all act on the population of an organism.
 Closed population = populations where
only births and deaths affect their
population size. These are normally only
found on islands, game reserves and
labs.
Limits on Populations
 Biotic Potential – the maximum number of offspring
that a species could produce if resources were
unlimited. Regulated by 4 important factors
 Birth potential - maximum number of offspring per
birth
 Capacity for survival – the number of offspring that
reach reproductive age
 Procreation – The number of times that a species
reproduces in a year
 Length of reproductive life. – The age of sexual
maturity and the number of years the individual
can reproduce.
Limits on Populations
 Limiting Factors – Any resource that is
in short supply is a limiting factor on a
population. Food, water, territory, and the
presence of pollutants.
 Carrying Capacity – The maximum
number of individual of a species that can
be supported indefinitely by the
ecosystem.
 Case Study