Biology OCR Module 6 Section Biology
6 Populations
OCR Module
and Sustainability
6 Section Biology
6Study
Populations
OCR
GuideModule
and
2026_2027.pdf
Sustainability
6 Section 6Study
Populations
Guide and
2026_2027.pdf
Sustainability Study Guide 2026_2027.pdf
Biology OCR Module 6 Section 6
Populations and Sustainability Study
Guide 2026/2027
Guidehttps://www.stuvia.com/dashboard!@_)#*)(@$)($@*($@)($@*_
Biology OCR Module 6 Section Biology
6 Populations
OCR Module
and Sustainability
6 Section Biology
6Study
Populations
OCR
GuideModule
and
2026_2027.pdf
Sustainability
6 Section 6Study
Populations
Guide and
2026_2027.pdf
Sustainability Study Guide 2026_2027.pdf
,Biology OCR Module 6 Section 6_ Populations and Sustainability.pdf Biology OCR Module 6 Section 6_ Populations and Sustainability.pdf Biology OCR Module 6 Section 6_ Populations and Sustainability.pdf
Terms in this set (62)
Limiting Factor An environmental resource or constraint that limits population growth.
Examples include, predators, disease, temperature and humidity.
Population Growth Curve It can be divided into 3 main phases:
- Phase 1: A period of slow growth. The small number of individuals that are
initially present reproduce increasing the total population. As the birth rate
is higher than the death rate, the population increases in size.
- Phase 2: A period of rapid growth. As the number of breeding individuals
increases, the total population multiplies exponentially. No constraints act
to limit the population explosion.
- Phase 3: A stable state: Further population growth is prevented by
external constraints. During this time the population size fluctuates, but
overall its size remains relatively stable. Birth rates and death rates are
approximately equal. Slight increases and decreases can be accounted for
by fluctuations in limiting factors, such the predators of predators
Biology OCR Module 6 Section 6_ Populations and Sustainability.pdf Biology OCR Module 6 Section 6_ Populations and Sustainability.pdf Biology OCR Module 6 Section 6_ Populations and Sustainability.pdf
,Biology OCR Module 6 Section 6_ Populations and Sustainability.pdf Biology OCR Module 6 Section 6_ Populations and Sustainability.pdf Biology OCR Module 6 Section 6_ Populations and Sustainability.pdf
Immigration The movement of individual organisms into a particular area, increasing
population size. E.g. millions of Christmas Island red crabs migrate each
year from forest to coast to reproduce, dramatically increasing the coastal
population of red crabs.
Emigration The movement of individual organisms away from an area, decreasing
population size. E.g. the Norway Lemming emigrates away form areas oh
high population density or poor habitat.
Biology OCR Module 6 Section 6_ Populations and Sustainability.pdf Biology OCR Module 6 Section 6_ Populations and Sustainability.pdf Biology OCR Module 6 Section 6_ Populations and Sustainability.pdf
, Biology OCR Module 6 Section 6_ Populations and Sustainability.pdf Biology OCR Module 6 Section 6_ Populations and Sustainability.pdf Biology OCR Module 6 Section 6_ Populations and Sustainability.pdf
Density Independent Factors Factors that have an effect on the whole population regardless of its size.
They can dramatically change the population size. Examples include,
earthquakes, fires, volcanic eruptions. In some cases these factors can
remove whole populations of a species from a region.
Interspecific competition Occurs when 2 or more different species of organism compete for the
same resource. It results in a reduction of the resource available to both
populations. One species is likely to outcompete the other.
Competitive Exclusion Principle Where two species are competing for limited resources, the one that uses
the resources will ultimately eliminate the other, outcompeting the other.
Example of Interspecific Competition Red and grey squirrels in the UK
Th grey squirrel was introduced to the wild in the UK and the numbers
quickly increased, resulting in the native red squirrels disappearing from
many areas. An increasing population of grey squirrels reduces the food
supply available to the red squirrels, reducing their ability to survive and
reproduce.
Biology OCR Module 6 Section 6_ Populations and Sustainability.pdf Biology OCR Module 6 Section 6_ Populations and Sustainability.pdf Biology OCR Module 6 Section 6_ Populations and Sustainability.pdf
6 Populations
OCR Module
and Sustainability
6 Section Biology
6Study
Populations
OCR
GuideModule
and
2026_2027.pdf
Sustainability
6 Section 6Study
Populations
Guide and
2026_2027.pdf
Sustainability Study Guide 2026_2027.pdf
Biology OCR Module 6 Section 6
Populations and Sustainability Study
Guide 2026/2027
Guidehttps://www.stuvia.com/dashboard!@_)#*)(@$)($@*($@)($@*_
Biology OCR Module 6 Section Biology
6 Populations
OCR Module
and Sustainability
6 Section Biology
6Study
Populations
OCR
GuideModule
and
2026_2027.pdf
Sustainability
6 Section 6Study
Populations
Guide and
2026_2027.pdf
Sustainability Study Guide 2026_2027.pdf
,Biology OCR Module 6 Section 6_ Populations and Sustainability.pdf Biology OCR Module 6 Section 6_ Populations and Sustainability.pdf Biology OCR Module 6 Section 6_ Populations and Sustainability.pdf
Terms in this set (62)
Limiting Factor An environmental resource or constraint that limits population growth.
Examples include, predators, disease, temperature and humidity.
Population Growth Curve It can be divided into 3 main phases:
- Phase 1: A period of slow growth. The small number of individuals that are
initially present reproduce increasing the total population. As the birth rate
is higher than the death rate, the population increases in size.
- Phase 2: A period of rapid growth. As the number of breeding individuals
increases, the total population multiplies exponentially. No constraints act
to limit the population explosion.
- Phase 3: A stable state: Further population growth is prevented by
external constraints. During this time the population size fluctuates, but
overall its size remains relatively stable. Birth rates and death rates are
approximately equal. Slight increases and decreases can be accounted for
by fluctuations in limiting factors, such the predators of predators
Biology OCR Module 6 Section 6_ Populations and Sustainability.pdf Biology OCR Module 6 Section 6_ Populations and Sustainability.pdf Biology OCR Module 6 Section 6_ Populations and Sustainability.pdf
,Biology OCR Module 6 Section 6_ Populations and Sustainability.pdf Biology OCR Module 6 Section 6_ Populations and Sustainability.pdf Biology OCR Module 6 Section 6_ Populations and Sustainability.pdf
Immigration The movement of individual organisms into a particular area, increasing
population size. E.g. millions of Christmas Island red crabs migrate each
year from forest to coast to reproduce, dramatically increasing the coastal
population of red crabs.
Emigration The movement of individual organisms away from an area, decreasing
population size. E.g. the Norway Lemming emigrates away form areas oh
high population density or poor habitat.
Biology OCR Module 6 Section 6_ Populations and Sustainability.pdf Biology OCR Module 6 Section 6_ Populations and Sustainability.pdf Biology OCR Module 6 Section 6_ Populations and Sustainability.pdf
, Biology OCR Module 6 Section 6_ Populations and Sustainability.pdf Biology OCR Module 6 Section 6_ Populations and Sustainability.pdf Biology OCR Module 6 Section 6_ Populations and Sustainability.pdf
Density Independent Factors Factors that have an effect on the whole population regardless of its size.
They can dramatically change the population size. Examples include,
earthquakes, fires, volcanic eruptions. In some cases these factors can
remove whole populations of a species from a region.
Interspecific competition Occurs when 2 or more different species of organism compete for the
same resource. It results in a reduction of the resource available to both
populations. One species is likely to outcompete the other.
Competitive Exclusion Principle Where two species are competing for limited resources, the one that uses
the resources will ultimately eliminate the other, outcompeting the other.
Example of Interspecific Competition Red and grey squirrels in the UK
Th grey squirrel was introduced to the wild in the UK and the numbers
quickly increased, resulting in the native red squirrels disappearing from
many areas. An increasing population of grey squirrels reduces the food
supply available to the red squirrels, reducing their ability to survive and
reproduce.
Biology OCR Module 6 Section 6_ Populations and Sustainability.pdf Biology OCR Module 6 Section 6_ Populations and Sustainability.pdf Biology OCR Module 6 Section 6_ Populations and Sustainability.pdf
