▁his ▁Philosoph ie ▁Zo ologique ▁( 1 8 0 9 ). ▁It ▁was ▁an ▁ups ide - down ▁tree ▁starting ▁with ▁w orm s ▁and ▁ending ▁with ▁m amm als . ▁However , ▁L amar ck ▁did ▁not ▁believe ▁in ▁common ▁descent ▁of ▁all ▁life . ▁Instead , ▁he ▁believed ▁that ▁life ▁consists ▁of ▁separate ▁parallel ▁lines ▁adv ancing ▁from ▁simple ▁to ▁complex . ▁ ▁The ▁American ▁ge ologist ▁Edward ▁H itch cock ▁( 1 7 9 3 – 1 8 6 4 ) ▁published ▁in ▁ 1 8 4 0 ▁the ▁first ▁tree ▁of ▁life ▁based ▁on ▁pale ont ology ▁in ▁his ▁Element ary ▁Ge ology . ▁On ▁the ▁vertical ▁axis ▁are ▁pale ont ological ▁periods . ▁H itch cock ▁made ▁a ▁separate ▁tree ▁for ▁plants ▁( left ) ▁and ▁animals ▁( right ). ▁The ▁plant ▁and ▁the ▁animal ▁tree ▁are ▁not ▁connected ▁at ▁the ▁bottom ▁of ▁the ▁chart . ▁Furthermore , ▁each ▁tree ▁starts ▁with ▁multiple ▁orig ins . ▁H itch cock ' s ▁tree ▁was ▁more ▁real istic ▁than ▁Dar win ' s ▁ 1 8 5 9 ▁theoretical ▁tree ▁( see ▁below ) ▁because ▁H itch cock ▁used ▁real ▁names ▁in ▁his ▁trees . ▁It ▁is ▁also ▁true ▁that ▁H itch cock ' s ▁trees ▁were ▁branch ing ▁trees . ▁However , ▁they ▁were ▁not ▁evolution ary ▁trees , ▁because ▁H itch cock ▁believed ▁that ▁a ▁de ity ▁was ▁the ▁agent ▁of ▁change . ▁That ▁was ▁an ▁important ▁difference ▁with ▁Dar win . ▁ ▁The ▁first ▁edition ▁of ▁Robert