Natural Selection And The Struggle For Existence Summary

Analytical Essay 1: Natural Selection and the Struggle for Existence by J. G. Lennox and B. E. Wilson
Lennox and Wilson begin their article with the assertion that the concept of a “struggle for existence” is crucial to Darwin’s conception of natural selection. They develop their argument in light of Lewontin’s example , where two bacterial strains of varying division rates grow logarithmically in a medium with a surplus of nutrients. In time, the faster dividing strain starts to compose increasingly larger portions of the bacteria present in the medium, emerging as dominant just by virtue of its division rate. Lewontin and L&W seem to believe that this demonstrates evolutionary change without ‘struggle,’ since environmental factors aren’t limiting reproduction rates . However, unlike Lewontin who then concludes that a struggle for existence isn’t necessary for natural selection to occur, L&W still hold that it is, and that it is important to now make a distinction …show more content…
To draw this distinction, they propose attributing evolutionary change in such “struggle for existence absent” cases as the bacteria example, to ‘differences in reproductive fitness,’ instead of just grouping it under Darwinian selection. They think this reconstruction allows differentiation between the different ways by which evolutionary change comes about, explaining the important underlying casual processes through which the changes occur. Recognizing the distinction between the ‘direct’ casual effect of the environment (through factors actively constraining reproductive success) on organisms in standard Darwinian cases, and the ‘indirect’ casual effect of the environment where it merely serves as a casually neutral backdrop to evolutionary changes emerging due to intrinsic differences in reproductive rates. Their above mentioned position appears to be hinged on Lewontin’s ability