, ▁rip arian ▁e col ogy , ▁and ▁others . ▁ ▁E cos ystem s ▁ ▁E cos ystem s ▁are ▁composed ▁of ▁a ▁variety ▁of ▁bi otic ▁and ▁ab i otic ▁components ▁that ▁function ▁in ▁an ▁inter related ▁way . ▁The ▁structure ▁and ▁composition ▁is ▁determined ▁by ▁various ▁environmental ▁factors ▁that ▁are ▁inter related . ▁Vari ations ▁of ▁these ▁factors ▁will ▁initi ate ▁dynamic ▁modifications ▁to ▁the ▁e cos ystem . ▁Some ▁of ▁the ▁more ▁important ▁components ▁are ▁soil , ▁atmosphere , ▁radiation ▁from ▁the ▁sun , ▁water , ▁and ▁living ▁organ isms . ▁ ▁Central ▁to ▁the ▁e cos ystem ▁concept ▁is ▁the ▁idea ▁that ▁living ▁organ isms ▁interact ▁with ▁every ▁other ▁element ▁in ▁their ▁local ▁environment . ▁Eug ene ▁Od um , ▁a ▁founder ▁of ▁e col ogy , ▁stated : ▁" Any ▁unit ▁that ▁includes ▁all ▁of ▁the ▁organ isms ▁( ie : ▁the ▁" community ") ▁in ▁a ▁given ▁area ▁interact ing ▁with ▁the ▁physical ▁environment ▁so ▁that ▁a ▁flow ▁of ▁energy ▁leads ▁to ▁clearly ▁defined ▁tro ph ic ▁structure , ▁bi otic ▁divers ity , ▁and ▁material ▁cycles ▁( i . e .: ▁exchange ▁of ▁materials ▁between ▁living ▁and ▁non l iving ▁parts ) ▁within ▁the ▁system ▁is ▁an ▁e cos ystem ." ▁Within ▁the ▁e cos ystem , ▁species ▁are ▁connected ▁and ▁dependent ▁upon ▁one ▁another ▁in ▁the ▁food ▁chain , ▁and ▁exchange ▁energy ▁and ▁matter ▁between ▁themselves ▁as ▁well ▁as ▁with ▁their ▁environment . ▁The ▁human ▁e cos ystem ▁concept ▁is ▁based ▁on ▁the ▁human