Download Populations Notes PPT

Populations
• Population – a group of
organisms of one
species living in a given
area at the same time
Factors Affecting Population
• Geographical Distribution –
Factors Affecting Population
• Geographical Distribution – range
inhabited by a species
Factors Affecting Population
• Geographical Distribution – range
inhabited by a species
• Density –
Factors Affecting Population
• Geographical Distribution – range
inhabited by a species
• Density – number of individuals per
unit area
Factors Affecting Population
• Geographical Distribution – range
inhabited by a species
• Density – number of individuals per
unit area
• Growth Rate –
Factors Affecting Population
• Geographical Distribution – range
inhabited by a species
• Density – number of individuals per
unit area
• Growth Rate – how fast a population
is able to increase in number
Factors Affecting Population
• Geographical Distribution – range
inhabited by a species
• Density – number of individuals per
unit area
• Growth Rate – how fast a population
is able to increase in number
o Birth rate – total number of live births per 1,000 per year
Factors Affecting Population
• Geographical Distribution – range
inhabited by a species
• Density – number of individuals per
unit area
• Growth Rate – how fast a population
is able to increase in number
o Birth rate – total number of live births per 1,000 people per year
o Death rate – number of deaths per 1,000 people per year
Factors Affecting Population
• Geographical Distribution – range
inhabited by a species
• Density – number of individuals per
unit area
• Growth Rate – how fast a population
is able to increase in number
o Birth rate – total number of live births per 1,000 people per year
o Death rate – number of deaths per 1,000 people per year
o Immigration – migration INTO a population
Factors Affecting Population
• Geographical Distribution – range
inhabited by a species
• Density – number of individuals per
unit area
• Growth Rate – how fast a population
is able to increase in number
o Birth rate – total number of live births per 1,000 people per year
o Death rate – number of deaths per 1,000 people per year
o Immigration – migration INTO a population
o Emigration – migration OUT OF a population
• Limiting Factor –
• Limiting Factor – something that causes a
population to decrease or prevents it from
growing limitlessly
• Limiting Factor – something that causes a
population to decrease or prevents it from
growing limitlessly
• Carrying Capacity (K) –
• Limiting Factor – something that causes a
population to decrease or prevents it from
growing limitlessly
• Carrying Capacity (K) – the maximum
number of individuals an environment can
sustain without detrimental effects
• Limiting Factor – something that causes a
population to decrease or prevents it from
growing limitlessly
• Carrying Capacity (K) – the maximum
number of individuals an environment can
sustain without detrimental effects
2 Types of Limiting
Factors
o Density-dependent –
2 Types of Limiting
Factors
o Density-dependent – factors that depend on the size of
the population
2 Types of Limiting
Factors
o Density-dependent – factors that depend on the size of
the population
• Only become limiting when the population density
becomes very high
2 Types of Limiting
Factors
o Density-dependent – factors that depend on the size of
the population
• Only become limiting when the population density
becomes very high
• Effects are intensified as the population density
increases
2 Types of Limiting
Factors
o Density-dependent – factors that depend on the size of
the population
• Only become limiting when the population density
becomes very high
• Effects are intensified as the population density
increases
o Density-independent –
2 Types of Limiting
Factors
o Density-dependent – factors that depend on the size of
the population
• Only become limiting when the population density
becomes very high
• Effects are intensified as the population density
increases
o Density-independent – factors that do not depend on
the size of the population
2 Types of Limiting
Factors
o Density-dependent – factors that depend on the size of
the population
• Only become limiting when the population density
becomes very high
• Effects are intensified as the population density
increases
o Density-independent – factors that do not depend on
the size of the population
• Are limiting regardless of the size of the population
2 Types of Limiting
Factors
o Density-dependent – factors that depend on the size of
the population
• Only become limiting when the population density
becomes very high
• Effects are intensified as the population density
increases
o Density-independent – factors that do not depend on
the size of the population
• Are limiting regardless of the size of the population
• Affect all populations in similar ways
Density Dependent Factors
Density Dependent Factors
• Predation
Density Dependent Factors
• Predation
o The effect of predation intensifies as the population density of
predators increases
Density Dependent Factors
• Predation
o The effect of predation intensifies as the population density of
predators increases
• Disease
Density Dependent Factors
• Predation
o The effect of predation intensifies as the population density of
predators increases
• Disease
o High population densities make the spread of disease easier to
transmit
Density Dependent Factors
• Predation
o The effect of predation intensifies as the population density of
predators increases
• Disease
o High population densities make the spread of disease easier to
transmit
• Parasitism
Density Dependent Factors
• Predation
o The effect of predation intensifies as the population density of
predators increases
• Disease
o High population densities make the spread of disease easier to
transmit
• Parasitism
o High densities make it easier for parasites to find hosts, and
spread diseases
Density Dependent Factors
• Predation
o The effect of predation intensifies as the population density of
predators increases
• Disease
o High population densities make the spread of disease easier to
transmit
• Parasitism
o High densities make it easier for parasites to find hosts, and
spread diseases
• Competition
Density Dependent Factors
• Predation
o The effect of predation intensifies as the population density of
predators increases
• Disease
o High population densities make the spread of disease easier to
transmit
• Parasitism
o High densities make it easier for parasites to find hosts, and
spread diseases
• Competition
o More members of a population = Less Available resources =
More competition
Density Dependent Factors
• Predation
o The effect of predation intensifies as the population density of
predators increases
• Disease
o High population densities make the spread of disease easier to
transmit
• Parasitism
o High densities make it easier for parasites to find hosts, and spread
diseases
• Competition
o More members of a population = Less Available resources = More
competition
o Less members of a population = More available resources = Less
competition
Density-Independent Factors
Density-Independent Factors
• Human Activities
Density-Independent Factors
• Human Activities
o Deforestation
o Over-hunting/fishing
Density-Independent Factors
• Human Activities
o Deforestation
o Over-hunting/fishing
• Natural Disasters
Density-Independent Factors
• Human Activities
o Deforestation
o Over-hunting/fishing
• Natural Disasters
o Hurricane, tornado, flood, severe drought
o Equally devastating to populations regardless of size
Density-Independent Factors
• Human Activities
o Deforestation
o Over-hunting/fishing
• Natural Disasters
o Hurricane, tornado, flood, severe drought
o Equally devastating to populations regardless of size
• Weather
Density-Independent Factors
• Human Activities
o Deforestation
o Over-hunting/fishing
• Natural Disasters
o Hurricane, tornado, flood, severe drought
o Equally devastating to populations regardless of size
• Weather
o Extremely hot/cold temperatures; frost
o Adversely effects all populations regardless of their size
Types of Growth
• Logistic Growth – population growth ↑
as resources ↑, and population growth ↓
as resources ↓
• Population
reaches a
carrying capacity
Types of Growth
• Exponential Growth – individuals in a
population reproduce at a constant rate
• Appears
to be
unlimited
growth