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TRANSCRIPT
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/export.php_files/ZooKeys-200-001-g007.jpg,
http://farm6.staticflickr.com/5191/7238292574_47bdff313f.jpg
Kelp Forest
Sea Urchins
Sea Otters
http://phycology.mlml.calstate.edu/images/Canopy.jpg, http://bioweb.uwlax.edu/bio203/s2008/bluske_brit/yawning.jpg
Characteristics of Populations
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.”
Characteristic # 1
http://www.tarsierfoundation.org/content/the-philippine-tarsier
•
Characteristic # 2
http://www.unisdr.org/, http://www.nscb.gov.ph/factsheet/pdf08/FS-200806-SS1-01.asp
3. Population dispersion
• Patterns of spacing in relation to other members of the population
• Clumped, uniform, random
Characteristic # 3
Concepts and Connections 2002 by Campbell
4. Growth rate, r
• change in the number of
individuals in a population
per unit time • Factors affecting population size:
1. # of births
2. # of deaths
3. # of individuals
leaving/entering
• Immigration = into
• Emigration = exit
# of individuals added
to/taken from the population
Characteristic # 4
If r = pop’n 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 = (b+i) – (d+e)
b vs. d growth rate i vs. e
? + ?
? - ?
? 0 ?
http://mysite.verizon.net/res15tbbv/sitebuildercontent/sitebuilderpicture
s/animal-migration.jpg, http://pull.imgfave.netdna-
cdn.com/image_cache/1288987440350429.jpeg
4. 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 ?!
Time (hrs) # of cells
0 1
1/3 2
2/3 4
1 8
2 ?
3 ?
: :
24 4.720 x 1021!!!
Characteristic # 4 (con’t)
http://www.emc.maricopa.edu/faculty/farabee/biobk/biobookmito.html
4. Growth rate, r
• Exponential growth
• Individuals in a
population reproduce at
a constant rate
• Logistic growth
• Population’s 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
J-curve S-curve
Characteristic # 4 (con’t)
lag
log
steady-state
4. 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
Characteristic # 4 (con’t)
http://www.sustainabilitylabs.org/page/sustainability-five-core-principles
Survivorship Curves
http://www.kv.k12.in.us/moodle/file.php/26/population_curve.jpg
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/Image/slow-down-sign.jpg
Factors Limiting Populations
• Competition
• Crowding and stress
• Human disturbances
• Natural catastrophes
• Parasitism and disease
• Predation
http://thumbs.imagekind.com/member/3f58d983-4020-4101-a3fb-1e3d67c818ac/uploadedartwork/650X650/d6b32ac0-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
Human Population Growth
Which model of pop’n growth (exp’l vs.
logistic) does the human pop’n follow?
Human pop’n size has increased through time
What factors have controlled human pop’n growth
through the centuries?
Centralized agriculture
Infectious disease
Industrial, technological revolutions
Modern medicine
http://www.bbc.co.uk/schools/gcsebitesize/science/images/bihumanpop.gif
Populations in developing vs.
industrialized countries
What does this graph tell us about
birth rates in different countries?
What about death rates?
Demographics Age structure and Sex-ratio
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?
http://www.bio.miami.edu/dana/pix/agestructure.gif
What are the effects
of human population
growth?
What are the effects
of different lifestyles?
http://kuro-kuro.org/wp-content/uploads/2010/10/population.jpg
Ecological Footprints http://www.myfootprint.org/en/