Population Dynamics

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Population Dynamics

• Characteristics of Populations
• Factors Limiting Populations
• Human Populations

http//filipinofreethinkers.org/wp-content/uploads
/2011/12/Philippine-Lugaw-Line.jpg,
http//www.pensoft.net/J_FILES/1/articles/2447/exp
ort.php_files/ZooKeys-200-001-g007.jpg,
http//farm6.staticflickr.com/5191/7238292574_47bd
ff313f.jpg
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http//phycology.mlml.calstate.edu/images/Canopy.j
pg, http//bioweb.uwlax.edu/bio203/s2008/bluske_br
it/yawning.jpg
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Characteristics of Populations
Characteristic 1

• Geographic distribution or range
• Area inhabited by a population
• The Philippine tarsier (Tarsius syrichta) is
  endemic to the southern Philippine islands of
  Bohol, Samar, Leyte and Mindanao, where it
  thrives mostly in secondary forests and dense
  patches or thickets of bush, tall grass and
  bamboo.

http//www.tarsierfoundation.org/content/the-phili
ppine-tarsier
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Characteristic 2

•  

http//www.unisdr.org/, http//www.nscb.gov.ph/fac
tsheet/pdf08/FS-200806-SS1-01.asp
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Characteristic 3

• Population dispersion
• Patterns of spacing in relation to other members
  of the population
• Clumped, uniform, random

Concepts and Connections 2002 by Campbell
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(No Transcript)
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Characteristic 4

• Growth rate, r
• change in the number of individuals in a
  population per unit time
• Factors affecting population size
• of births
• of deaths
• of individuals leaving/entering
• Immigration into
• Emigration exit
• ? of individuals added to/taken from the
  population

• If r popn growth rate
• b birth rate/natality
• d death rate/mortality
• i rate of immigration
• e rate of emigration
• Express r in terms of b, d, i, and e.
• r (bi) (de)

b vs. d growth rate i vs. e
? ?
? - ?
? 0 ?
http//mysite.verizon.net/res15tbbv/sitebuildercon
tent/sitebuilderpictures/animal-migration.jpg,
http//pull.imgfave.netdna-cdn.com/image_cache/128
8987440350429.jpeg
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Characteristic 4 (cont)

• Growth rate, r
• Exponential growth
• Individuals in a population reproduce at a
  constant rate
• ex. bacterial reproduction binary fission

Time (hrs) of cells
0 1
1/3 2
2/3 4
1 8
2 ?
3 ?

24 4.720 x 1021!!!
Time (hrs) of cells
0 1
1/3 2
2/3 4
1 8
2 ?
3 ?

24 ?!
http//www.emc.maricopa.edu/faculty/farabee/biobk/
biobookmito.html
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Characteristic 4 (cont)

• Growth rate, r
• Exponential growth
• Individuals in a population reproduce at a
  constant rate

• Logistic growth
• Populations growth slows/stops following a
  period of exponential growth

Time (hrs) of cells
0 1
1/3 2
2/3 4
1 8
2 ?
3 ?

24 4.720 x 1021
steady-state
log
J-curve
S-curve
lag
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Characteristic 4 (cont)

• Growth rate, r
• Logistic growth
• Biotic potential, rmax
• Max rate at w/c a population could increase under
  ideal conditions
• Environmental resistance
• Unfavorable conditions that prevent a population
  from reaching its rmax
• Carrying capacity, K
• Max of individuals a given environment could
  support with its limited resources

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http//www.sustainabilitylabs.org/page/sustainabil
ity-five-core-principles
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Survivorship Curves
http//www.kv.k12.in.us/moodle/file.php/26/populat
ion_curve.jpg
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Factors Limiting Populations

• Limiting factor - factor that causes population
  growth to decrease
• Density-dependent factors
• Becomes limiting only when population reaches a
  certain level mostly biotic factors
• Density-independent factors
• Affects all populations in similar ways,
  regardless of population size mostly abiotic
  factors

http//www.cpsu.org.au/multiattachments/17146/Imag
e/slow-down-sign.jpg
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Factors Limiting Populations

• Competition
• Crowding and stress
• Human disturbances
• Natural catastrophes
• Parasitism and disease
• Predation

http//thumbs.imagekind.com/member/3f58d983-4020-4
101-a3fb-1e3d67c818ac/uploadedartwork/650X650/d6b3
2ac0-cede-4422-882d-1723572d56f7.jpg,
http//reachthetribes.com/200909/big/kaingin.JPG,
http//static.guim.co.uk/sys-images/Technology/Pix
/pictures/2009/10/21/1256124500714/Mount-Pinatubo-
eruption-i-001.jpg, http//s3.hubimg.com/u/593274_
f260.jpg
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Human Population Growth

• Which model of popn growth (expl vs.
  logistic) does the human popn follow?
• Human popn size has increased through time
• What factors have controlled human popn growth
  through the centuries?
• Centralized agriculture
• Infectious disease
• Industrial, technological revolutions
• Modern medicine

http//www.bbc.co.uk/schools/gcsebitesize/science/
images/bihumanpop.gif
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Populations in developing vs. industrialized
countries

• What does this graph tell us about birth rates in
  different countries?
• What about death rates?

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DemographicsAge structure and Sex-ratio
http//www.bio.miami.edu/dana/pix/agestructure.gif

• What do these graphs tell us about birth rates in
  different countries?
• What about death rates?
• What can age structure diagrams tell us about the
  population?

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• What are the effects of human population growth?
• What are the effects of different lifestyles?

http//kuro-kuro.org/wp-content/uploads/2010/10/po
pulation.jpg
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Ecological Footprints
http//www.myfootprint.org/en/