5.2+Limits+to+Growth_Density+Independent+Factors_6th

SEAN, CHRISTIAN, and TIM ** __Density Independent Factors__ ** **- a factor that affects all populations in similar ways, regardless of size**
 * Unusual weather, natural disasters, seasonal cycles, and human activities are examples of independant factors
 * species show characteristic crashes after event
 * species can adapt to changing environments, but major upsets can lead to long term declies in certain populations (Sean) 
 * when an independant factor occurs any population may get wiped out temporarily, but eventually the population may revive itself, although, in many cases, the species has become extinct.
 * Human technology can serve as a independant limiting factor because we cut down trees to create room and we use them for wood and paper. This then ruins many animal's habitats. If we left them alone afterwords the species would grow back.
 * In one case, the volcano Mt. Saint Helens erupted and killed all of the trees surrounding it. After a while the trees started to grow back and when they did they came back more abundantly.
 * Global Warming is an independant factor because it is increasing the Earth's temperature, and that may result in the ruining of a population like the Polar Bears (Christian)
 * Ecological niche= the "role" a species "plays" in the ecosystem.
 * The ecological niche of a species,therefore, includes not justnot just the speces habitat but also the ways they interact with other species and the physical enviorment.
 * Population denisity is the number of individauls per a unit area.
 * Denisty Independent Factors are physical factors, such as weather or harmful chemicals.
 * Many populations controlled by density-independent factors have the second growth form, or the "resource-limited" type. There is much less biological control and the control is a more haphazard, physical control.
 * The population size often goes over the carrying capacity before some other physical factor decreases the population size. Unlike the case for density-dependent factors, in populations being controlled by density-independent factors, growth rates do not seem to show any trend at all relative to population density **(**[|http://nsm1.][[image:http://rds.yahoo.com/_ylt=A0WTefXkhL1J_agAgpejzbkF/SIG=13em90q4m/EXP=1237243492/**http%3A//www.soest.hawaii.edu/MET/Faculty/businger/images/notes/2Mt._St._Helens_Eruption.jpg width="368" height="402" link="http://nsm1.nsm.iup.edu/rwinstea/popreg.shtm"]][|ns][[image:http://rds.yahoo.com/_ylt=A0WTefi0g71J4MUA9AGjzbkF/SIG=12ake4aje/EXP=1237243188/**http%3A//www.westcolumbiapolice.org/images/hurricane.jpg width="375" height="402" link="http://nsm1.nsm.iup.edu/rwinstea/popreg.shtm"]][|m.iup.edu/rwinstea/popreg.shtm] ) ([|Mt St. Helens Factoids]) (Tim)