Populations and communities%2c ecosystems %26 change

Populations and communities%2c ecosystems %26 change -...

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Populations and  Communities
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What we will cover – first, populations and communities be sure to have read chapter 4 you will have read about population growth limits on growth community interactions evolution and change
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Population Dynamics: Growth Curves all species have the capacity to increase exponentially under ideal conditions Exponential growth  re s ults  in a  “J-c urve ” if we  plo t P o pula tio n S ize   ve rs us  Tim e Population Size = Births + Immigration – Deaths - Emigration Population— a  g ro up o f individua ls  o f the  s a m e  s pe c ie s  tha t live  in a   de fine d a re a  a nd ha ve  the  po te ntia l to  inte rb re e d 
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Example of Exponential growth: Muskox introduced to an island with no predators and abundant resources
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Population Growth exponential growth is rare in nature and usually cannot be sustained by populations over  the long term eventually, resources become limiting and the population decreases, sometimes showing a  real crash phase
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Biotic Potential— a b ility o f a  po pula tio n to   inc re a s e   Environmental Resistance —c o m b ina tio n o f a ll the  a b io tic  a nd b io tic   fa c to rs  tha t lim it po pula tio n inc re a s e Environmental resistance often limits population growth by reducing  recruitment the  s urviva l o f o ffs pring  to  the  a dult b re e ding  s ta g e Po pula tio n s ize  is  de te rm ine d b y a  dyna m ic  b a la nc e  b e twe e n b io tic   po te ntia l o f a  s pe c ie s  a nd the  e nviro nm e nta l re s is ta nc e  tha t individua ls   e nc o unte r Population Growth What factors determine biotic potential for a species? What factors contribute to environmental resistance?
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This note was uploaded on 10/28/2011 for the course NRES 102 taught by Professor David during the Fall '11 term at University of Illinois at Urbana–Champaign.

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Populations and communities%2c ecosystems %26 change -...

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