▁World : ▁The ▁Dom us ▁Complex ▁▁ ▁Scott ' s ▁point ▁in ▁this ▁chapter ▁is ▁that ▁humans ▁domestic ated ▁the ▁planet ▁more ▁extens ively ▁than ▁t aming ▁cattle ▁and ▁plant ing ▁cro ps , ▁and ▁that ▁this ▁had ▁deep ▁consequences . ▁He ▁exam ines ▁the ▁changes ▁that ▁man kind ▁has ▁brought ▁to ▁its ▁environment ▁by ▁being ▁an ▁artificial ▁natural ▁selection ▁of ▁sorts , ▁to ▁bring ▁out ▁plant ▁types ▁that ▁are ▁now ▁un recogn izable ▁from ▁their ▁pro gen itors ▁and ▁are ▁also ▁unable ▁to ▁surv ive ▁without ▁human ▁care . ▁We ▁also ▁domestic ated ▁animals ▁by ▁casting ▁out ▁those ▁with ▁und es ired ▁characteristics ▁and ▁cultiv ating ▁that ▁which ▁ple ases ▁us . ▁This ▁changed ▁animals ▁both ▁in ▁behavior ▁and ▁phys i olog ically , ▁making ▁them ▁perman ently ▁do cile ▁and ▁un - re active , ▁while ▁also ▁having ▁smaller ▁bra ins . ▁These ▁changes ▁have ▁negative ▁effects ▁upon ▁the ▁animals ▁themselves , ▁though ▁they ▁do ▁result ▁in ▁a ▁positive ▁effect ▁in ▁output ▁for ▁their ▁domestic ators . ▁ ▁Scott ▁then ▁turns ▁to ▁what ▁he ▁calls ▁" H uman ▁Par alle ls ," ▁ways ▁in ▁which ▁human ▁be ings ▁themselves ▁might ▁have ▁been ▁transformed ▁by ▁domestic ation . ▁From ▁the ▁alter ed ▁b one ▁structures ▁of ▁women ▁who ▁were ▁forced ▁into ▁agricult ural ▁labor ▁to ▁general ▁size ▁difference ▁and ▁proof ▁of ▁nut r ition ▁def ic its ▁in ▁post - ag ric ulture ▁man kind , ▁Scott ▁arg ues ▁that ▁humans ▁have ▁b red ▁their ▁own ▁irre vers ible ▁change . ▁Scott