the struggle for existence
... that the idea of the struggle for existence was influential in Darwin's Theory of Evolution, but he got the idea from a famous economist?
... that the idea of <b id="mwCFw"><a class="mw-redirect" href="./The_struggle_for_existence" id="mwCF0" rel="mw:WikiLink" title="The struggle for existence">the struggle for existence</a></b> was influential in Darwin's Theory of Evolution, but he got the idea from a famous economist?