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PopulationsPopulations
A particular species living in a A particular species living in a particular place at the same particular place at the same timetime
Population GrowthPopulation Growth
Biotic Potential:Biotic Potential: The highest rate The highest rate of reproduction a population can of reproduction a population can reach. reach.
Sentence:Sentence:
Population GrowthPopulation Growth
Biotic Potential:Biotic Potential: The highest rate The highest rate of reproduction a population can of reproduction a population can reach. reach.
Sentence:Sentence: The The biotic potentialbiotic potential of of fruit flies is reached when 120 fruit flies is reached when 120 eggs laid by the female hatch into eggs laid by the female hatch into successful offspring. successful offspring.
Fruit Fly Population Fruit Fly Population GrowthGrowth GenerationGeneration
11
22
33
44
55
66
77
# of Offspring# of Offspring
Fruit Fly Population Fruit Fly Population GrowthGrowth GenerationGeneration
11
22
33
44
55
66
77
# of Offspring# of Offspring
120120
Fruit Fly Population Fruit Fly Population GrowthGrowth GenerationGeneration
11
22
33
44
55
66
77
# of Offspring# of Offspring
120120
7,2007,200
Fruit Fly Population Fruit Fly Population GrowthGrowth GenerationGeneration
11
22
33
44
55
66
77
# of Offspring# of Offspring
120120
7,2007,200
432,000432,000
Fruit Fly Population Fruit Fly Population GrowthGrowth GenerationGeneration
11
22
33
44
55
66
77
# of Offspring# of Offspring
120120
7,2007,200
432,000432,000
25,920,00025,920,000
Fruit Fly Population Fruit Fly Population GrowthGrowth GenerationGeneration
11
22
33
44
55
66
77
# of Offspring# of Offspring
120120
7,2007,200
432,000432,000
25,920,00025,920,000
1,555,200,0001,555,200,000
Fruit Fly Population Fruit Fly Population GrowthGrowth GenerationGeneration
11
22
33
44
55
66
77
# of Offspring# of Offspring
120120
7,2007,200
432,000432,000
25,920,00025,920,000
1,555,200,0001,555,200,000
93,312,000,00093,312,000,000
Fruit Fly Population Fruit Fly Population GrowthGrowth GenerationGeneration
11
22
33
44
55
66
77
# of Offspring# of Offspring
120120
7,2007,200
432,000432,000
25,920,00025,920,000
1,555,200,0001,555,200,000
93,312,000,00093,312,000,000
5,598,720,000,0005,598,720,000,000
Fly generations
Num
ber o
f Flies
Fly generations
Num
ber o
f Flies
The graph looks like the shape of what letter?
Population GrowthPopulation Growth
We call this type of curve a We call this type of curve a JJ – – shaped shaped
curve and the population growth curve and the population growth it it
represents represents exponential growthexponential growth
Population Growth Population Growth (cont.)(cont.) Population may be limited by Population may be limited by
factors called factors called Limiting FactorsLimiting Factors. .
Examples:Examples:
Population Growth Population Growth (cont.)(cont.) Population may be limited by Population may be limited by
factors called factors called Limiting FactorsLimiting Factors. .
Examples:Examples:– WaterWater– ShelterShelter– NutrientsNutrients– MatesMates– Nesting SitesNesting Sites
Population GrowthPopulation Growth
Carrying Capacity:Carrying Capacity: The maximum The maximum population of a particular species population of a particular species that a given habitat can support that a given habitat can support over a given period of time.over a given period of time.
S - shaped Growth S - shaped Growth CurveCurve
Time
Num
ber o
f In
div
iduals in
the
popula
tion
K = Carrying Capacity
Growth = Births exceed DeathsGrowth = Births exceed Deaths Decline = Deaths exceed BirthsDecline = Deaths exceed Births
Natality: birthrate; the production of Natality: birthrate; the production of new individuals by birth, hatching, new individuals by birth, hatching, germination, or cloning.germination, or cloning.
Mortality: deathrate; the ratio of Mortality: deathrate; the ratio of deaths in an area to the population of deaths in an area to the population of that area. that area.
Immigration: migration into a place Immigration: migration into a place
Emigration: migration out of a place Emigration: migration out of a place
Num
ber o
f In
div
iduals in
the
popula
tion
K = Carrying Capacity
Time
The number of organisms in a population tends to rise above and fall below the carrying capacity.
Limiting FactorsLimiting Factors Limiting Factor: an Limiting Factor: an
environmental factor that limits environmental factor that limits the growth, abundance, or the growth, abundance, or distribution of a population of distribution of a population of organisms in an ecosystem (e.g. organisms in an ecosystem (e.g. water, nutrients, sunlight, prey, water, nutrients, sunlight, prey, etc.).etc.).
1.1. Density DependentDensity Dependent
2.2. Density Independent Density Independent
Density DependentDensity Dependent
Examples:Examples:
Density DependentDensity Dependent
Examples:Examples:– FoodFood– WaterWater– Living SpaceLiving Space– PredationPredation– Disease:Disease: High densities makes it easier
for parasites to find hosts and spread the disease
– Stress: usually has a negative effect on populations. Stress can make organisms weak and more prone to disease.
Density IndependentDensity Independent
Examples:Examples:
Density IndependentDensity Independent
Examples:Examples:
– Natural Disasters/Weather Natural Disasters/Weather
(e.g. drought, hurricane, (e.g. drought, hurricane, flood, fire)flood, fire)
– SunlightSunlight– TemperatureTemperature– Human ActivitiesHuman Activities
Population Growth Population Growth Practice:Practice:
Bacteria reproduce by splitting (binary Bacteria reproduce by splitting (binary fission). A certain species reproduces fission). A certain species reproduces every 20 minutes. If we start with one every 20 minutes. If we start with one bacterial cell, how many cells will there bacterial cell, how many cells will there be at the end of 3hrs? be at the end of 3hrs?
Show your work in the form of a Show your work in the form of a population GRAPH. The independent population GRAPH. The independent variable is variable is TIMETIME and the dependent and the dependent variable is the variable is the GROWTH/NUMBERGROWTH/NUMBER of of bacteria.bacteria.
Data:
Time Number of (in minutes) Bacteria
0 min 120 min40 min60min (1hr)80 min100 min120 min (2hrs)140 min160 min180 min (3hrs)
Note: Graph the time in Note: Graph the time in minutesminutes
