24.1 Population Size Flashcards
Definition of limiting factor
a environmental resource or constraint that limits population growth
Why are limiting factors necessary?
-they prevent population explosion (further growth)
-make sure resources do not run out for entire ecosystems
What are abiotic factors?
non-living factors (that shape an environment)
What are examples of abiotic factors?
-temperature
-humidity
-pH
-light
-availability of of oxygen and water
What is a biotic factor
living factors (that shape an environment)
Examples of biotic factors?
-predators
-disease
-competition
-viruses
Definition of Carrying Capacity
the maximum population size that an environment can support
Definition of Immigration
the movement of individual organisms into a specific area increases the population size
Define Emmigration
the movement of individual organisms away from a specific area decreases the population size
What are density independent factors?
factors that have an effect on the whole population regardless of its size which cab dramatically change population size
What are Examples of Density Independent Factors
-Earthquakes
-Volcanoes
-Storms
What are the three phases of the population growth curve?
Phase 1 - lag phase, slow growth
Phase 2 - exponential phase, rapid growth
Phase 3 - stationary phase, stable state
Explain what is happening during Phase 1 of the population growth curve?
-lag phase
-a period of slow growth
-small number of individuals reproducing increasing the population
-birth rate is greater than the death rate
-the population increases in size
Explain what is happening during Phase 2 of the population growth curve?
-rapid growth
-number of breeding individuals increases
-the total population multiplies exponentially
-no constraints act to limit the population explosion
Explain what is happening during Phase 3 of the population growth curve?
-stable state
-further population growth is prevented by external constraints
-during this population fluctuates but overall is relatively stable
-birth and death rates approximately equal
-slight increases and decreases can be accounted for by fluctuations in limiting factors
