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POPULATION ECOLOGY
Steve Lonhart / NOAA MBNMS
Kathy DeWet-‐Oleson / NOAA
Steve Lonhart / NOAA MBNMS
1
LEVELS OF ECOLOGY • Popula=on = all the individuals of a species that live in the same area
M/Y/D/S Animal Graphics 2
POPULATION SIZE How does popula=on size change? • Births • Deaths • Immigra=on • Emigra=on
I
E
Steve Choy / NOAA MBNMS
CA Fish & Game
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POPULATION SIZE
Nt+1= Nt B D I E + + - -
Steve Choy / NOAA MBNMS
CA Fish & Game
4
POPULATION SIZE Scien=sts observed 2,813 sea oVers along the Central Coast in 2009. 430 oVers died and 328 pups were born. If there is no immigra=on or emigra=on, how many sea oVers were there in 2010?
Informa=on from OVer Project & USGS
2,813 +328 – 430 + 0 -‐ 0 = 2,711
Nt+1= Nt B D I E + + - - 5
POPULATION SIZE If 10 sea oVers leave the Central Coast popula=on and 2 enter, what would the 2010 popula=on be?
2,711+2-‐10=2,703
Nt+1= Nt B D I E + + - -
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POPULATION SIZE
US Geological Survey
Steve Choy / NOAA MBNMS
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POPULATION GROWTH
Genera&on 1 2 3 4 5
Popula=on Size 2 4 8 16 32 8
POPULATION GROWTH
Exponen&al Growth
Time
Popu
la=o
n Size
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POPULATION GROWTH Why don’t popula=ons
usually grow exponen=ally?
• Limited resources – light, water, nutrients, food, space
• Disease • Preda=on
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POPULATION GROWTH
Logis&c Growth
Exponen&al Growth
Carrying Capacity
Time
Popu
la=o
n Size
K
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POPULATION GROWTH Num
ber o
f pup
s born
Year
Elephant Seals
hVp://www.nmfs.noaa.gov/pr/pdfs/sars/po2007sene-‐ca.pdf
Carrying capacity
Photos by Kris=n McCully 12
ACTIVITY
Map of Average Annual Popula=on Growth Rate, 1980-‐1998
(hVp://www.worldbank.org/depweb/english/modules/social/pgr/) 13