Section 14-3 and 14-4 “Population” Write everything that is underlined.

Section 14-3 and 14-4Section 14-3 and 14-4“Population”“Population”

Write everything Write everything that isthat is underlinedunderlined

14.3 Population Density / 14.4 Population Growth

Section 14.3 KEY CONCEPT: Section 14.3 KEY CONCEPT: Each population has a density, a Each population has a density, a dispersion, and a reproductive strategy.dispersion, and a reproductive strategy.


I.I. PopulationsPopulations

1.1. Population density isPopulation density is a measurement a measurement of of the number of individuals living in a the number of individuals living in a defined spacedefined space..

2.2. Population dispersionPopulation dispersion refers to refers to how a how a population is spread in an areapopulation is spread in an area..

• There are three types of dispersion There are three types of dispersion illustrated on the next slides:illustrated on the next slides:


a. clumpeda. clumped


b.uniformb.uniform


c. randomc. random


• Survivorship curves:Survivorship curves:– Type I: low level of infant mortality and an older Type I: low level of infant mortality and an older

populationpopulation– common to large mammals and humanscommon to large mammals and humans

– Type II: survivorship rate is equal at all stages Type II: survivorship rate is equal at all stages of lifeof life– common to birdscommon to birds

and reptilesand reptiles– Type III: very high Type III: very high

birth rate, very high birth rate, very high infant mortalityinfant mortality

– common to invertebrates common to invertebrates and plantsand plants


Section 14.4 KEY CONCEPT: Section 14.4 KEY CONCEPT: Populations grow in predictable Populations grow in predictable patterns.patterns.


I.I. Population GrowthPopulation Growth1.1. The size of a population is always The size of a population is always

changingchanging..2.2. Four factors affect the size of a Four factors affect the size of a

populationpopulation::a.a. Births Births b.b. DeathsDeathsc.c. ImmigrationImmigration

(Moving into an area)(Moving into an area)

d.d. EmigrationEmigration(Moving out of an area)(Moving out of an area)


3.3.ExponentialExponential growth is a growth is a rapid rapid population increase due topopulation increase due to an an abundance (abundance (lots oflots of) of) of resources resources..


4.4. LogisticLogistic growth growth is due to a population is due to a population facing limited resourcesfacing limited resources. .


5.5.Carrying capacity is the Carrying capacity is the maximum number of maximum number of individualsindividuals in a population in a population that that the environment can the environment can supportsupport..

• This is due to limited resources This is due to limited resources (food, shelter, space)(food, shelter, space)


• A population crash is a dramatic A population crash is a dramatic decline in the size of a population decline in the size of a population over a short period of time.over a short period of time.


6.6. A A limiting factorlimiting factor is something that is something that keeps the size of a population downkeeps the size of a population down. .

• Limiting factors can depend on the Limiting factors can depend on the density of individuals in the population density of individuals in the population or not.or not.


7.7. Density-dependentDensity-dependent limiting factors are limiting factors are affected by the number of individuals affected by the number of individuals in a given areain a given area..

– PredationPredation

– CompetitionCompetition

– Parasitism Parasitism and diseaseand disease


8.8.Density-independentDensity-independent limiting limiting factors limit a population’s growth factors limit a population’s growth regardless of the densityregardless of the density..

a.a.unusual unusual weatherweather

b.b.natural natural disastersdisasters

c.c.human human activitiesactivities

Section 14-3 and 14-4 “Population” Write everything that is underlined.

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Transcript of Section 14-3 and 14-4 “Population” Write everything that is underlined.