<story><title>When sexual selection can lead to a decline in the capacity for survival</title><url>https://www.nytimes.com/2017/05/05/opinion/sunday/are-these-birds-too-sexy-to-survive.html</url></story><parent_chain></parent_chain><comment><author>kevinalexbrown</author><text>I remember once from undergrad the saying &amp;#x27;&amp;quot;obvious&amp;quot; is the most dangerous word in mathematics.&amp;#x27; Seeing how something &lt;i&gt;could be&lt;/i&gt; true is dramatically different from identifying and defending that it &lt;i&gt;is&lt;/i&gt; true.&lt;p&gt;It&amp;#x27;s dangerously easy to say &amp;quot;oh yea, makes sense, natural selection happens by mating so if mates choose club wings, I get it. Obvious.&amp;quot; But Prum&amp;#x27;s trying to go a step further, and test just how far out of balance and arbitrary the mate selection part can be from the direct do-not-die part of evolutionary fitness.&lt;p&gt;He proposes that we can differentiate between these two by considering that the club wings aren&amp;#x27;t actually indicators of higher direct fitness, because they hurt the ability to fly, even among females that have no need for such shenanagins. I&amp;#x27;m not sure I totally agree with or grasp that, but at least it&amp;#x27;s an attempt to further understand and test the idea.&lt;p&gt;I&amp;#x27;m frankly surprised by comments accusing a well established evolutionary biologist of severely misunderstanding natural selection. The author has spent his career, among other things, investigating mechanisms of evolution, and identifying and performing tests to assess their relative importance to a particular species (here&amp;#x27;s an example: &lt;a href=&quot;http:&amp;#x2F;&amp;#x2F;prumlab.yale.edu&amp;#x2F;sites&amp;#x2F;default&amp;#x2F;files&amp;#x2F;prum_1997_phylogenetic_tests.pdf&quot; rel=&quot;nofollow&quot;&gt;http:&amp;#x2F;&amp;#x2F;prumlab.yale.edu&amp;#x2F;sites&amp;#x2F;default&amp;#x2F;files&amp;#x2F;prum_1997_phylog...&lt;/a&gt;).&lt;p&gt;You might consider whether your objections are addressed in his work not aimed at the lay population, and that your criticism really just amounts to &amp;quot;He wrote this at not exactly the right level of sophistication for me.&amp;quot; Maybe that&amp;#x27;s true, but it&amp;#x27;s a pretty boring claim.</text></comment>
<story><title>When sexual selection can lead to a decline in the capacity for survival</title><url>https://www.nytimes.com/2017/05/05/opinion/sunday/are-these-birds-too-sexy-to-survive.html</url></story><parent_chain></parent_chain><comment><author>skywhopper</author><text>I will just echo the other posts here that the author of this article or his sources severely misunderstand natural selection and the special case of sexual selection. The most important thing to understand about evolution is that natural selection can only work with the existing traits of an organism, the current environment in which the organism exists, and what random changes happen. Furthermore, every change in the phenotype of an organism has a number of sometimes disparate impacts on its likelihood of reproductive success within its own environment. Given all of that, we should _expect_ to see seeming contradictions like this example.&lt;p&gt;Most birds can fly because their parents could fly. The genes for flying stick around because so many other traits of birds have evolved to benefit or rely on the ability to fly. But that doesn&amp;#x27;t mean flying itself is some magical end goal. Flying is only useful for natural selection insasmuch as it grants the organism a better likelihood of reproducing.&lt;p&gt;Why would natural selection necessarily prefer birds that are ideally designed for flying in what we perceive as a graceful manner? In fact, we know that it doesn&amp;#x27;t. Ostriches, emus, and penguins can&amp;#x27;t fly, though their ancestors were able to. That is not evidence that they are evolutionary dead ends. The huge variety of penguin species that have evolved since the ancestor of penguins lost the ability to fly proves the opposite, in fact.&lt;p&gt;This bird clearly flies well enough to continue to survive. If the traits that work against it flying gracefully grant it more reproductive success than flying slightly better would, then natural selection will favor those traits.&lt;p&gt;Natural selection is often treated far too preciously. Sure, it took a  genius in Darwin to identify and clearly describe the phenomenon, but the process itself is tautological. It comes down to, &amp;quot;the things that reproduce better reproduce better&amp;quot;. This bird exists, therefore natural selection favored its traits. If we don&amp;#x27;t understand why, the failure is ours, not natural selection.</text></comment>