{"id":4737,"date":"2014-06-18T20:47:17","date_gmt":"2014-06-18T19:47:17","guid":{"rendered":"http:\/\/theskepticalzone.com\/wp\/?p=4737"},"modified":"2014-06-19T04:59:14","modified_gmt":"2014-06-19T03:59:14","slug":"counterintuitive-evolutionary-truths","status":"publish","type":"post","link":"http:\/\/theskepticalzone.com\/wp\/counterintuitive-evolutionary-truths\/","title":{"rendered":"Counterintuitive evolutionary truths"},"content":{"rendered":"

In the Roger Scruton on altruism<\/b><\/a> thread, some commenters have expressed confusion over the evolutionary explanation of altruism in ants.  If workers and soldiers leave no offspring, then how does their altruistic behavior get selected for?<\/p>\n

<\/p>\n

The answer is simple but somewhat counterintuitive. The genes for altruistic behavior are present in both the workers\/soldiers and in their parents. Self-sacrificing behavior in the workers and soldiers is bad for their<\/i> copies of these genes, but it promotes the survival and proliferation of the copies contained in the queen and in her store of sperm. As long as there is a net reproductive benefit to the genes, such altruistic behaviors can be maintained in the population. <\/p>\n

Selfish genes, altruistic individuals.<\/p>\n

Let’s dedicate this thread to a discussion of other counterintuitive evolutionary truths. Here are some of my favorites:<\/p>\n

1. The classic example of sickle-cell trait in humans. Why is a disease-causing mutation maintained in a human population? Shouldn’t selection eliminate the mutants? Not in this case, because only the unfortunate folks who have two<\/i> copies of the allele get the disease. People with one copy of the allele don’t get the disease, but they do receive a benefit: improved resistance to malaria. In effect, the people with the disease are paying for the improved health of the people with only one copy of the mutation. <\/p>\n

(Kinda makes you wonder why the Designer did it that way, doesn\u2019t it?)<\/p>\n

2. In utero cannibalism in sharks:<\/a><\/p>\n

\n

Shark embryos cannibalize their littermates in the womb, with the largest embryo eating all but one of its siblings.<\/p>\n

Now, researchers know why: It’s part of a struggle for paternity in utero, where babies of different fathers compete to be born.<\/p>\n

The researchers, who detailed their findings today (April 30) in the journal Biology Letters, analyzed shark embryos found in sand tiger sharks (Carcharias taurus) at various stages of gestation and found that the later in pregnancy, the more likely the remaining shark embryos had just one father.<\/p>\n<\/blockquote>\n

(Kinda makes you wonder why the Designer did it that way, doesn\u2019t it?)<\/p>\n

3. Genetic conflict between parents and offspring. Here\u2019s a great example from a 1993 paper by David Haig<\/a>: <\/p>\n

Pregnancy has commonly been viewed as a cooperative interaction between a mother and her fetus. The effects of natural selection on genes expressed in fetuses, however, may be opposed by the effects of natural selection on genes expressed in mothers. In this sense, a genetic conflict can be said to exist between maternal and fetal genes. Fetal genes will be selected to increase the transfer of nutrients to their fetus, and maternal genes will be selected to limit transfers in excess of some maternal optimum. Thus a process of evolutionary escalation is predicted in which fetal actions are opposed by maternal countermeasures. The phenomenon of genomic imprinting means that a similar conflict exists within fetal cells between genes that are expressed when maternally derived, and genes that are expressed when paternally derived.<\/p><\/blockquote>\n

(Kinda makes you wonder why the Designer did it that way, doesn’t it?)<\/p>\n

Can readers think of other counterintuitive evolutionary truths?<\/p>\n

Addendum<\/b><\/p>\n<\/p>\n

4. Mutant organism loses its innate capacity to reproduce and becomes a great evolutionary success. Can anyone guess which organism(s) I’m thinking of?<\/p>\n","protected":false},"excerpt":{"rendered":"

In the Roger Scruton on altruism thread, some commenters have expressed confusion over the evolutionary explanation of altruism in ants.  If workers and soldiers leave no offspring, then how does their altruistic behavior get selected for?<\/p>\n","protected":false},"author":20,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[],"class_list":["post-4737","post","type-post","status-publish","format-standard","hentry","category-uncategorized"],"_links":{"self":[{"href":"http:\/\/theskepticalzone.com\/wp\/wp-json\/wp\/v2\/posts\/4737","targetHints":{"allow":["GET"]}}],"collection":[{"href":"http:\/\/theskepticalzone.com\/wp\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/theskepticalzone.com\/wp\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/theskepticalzone.com\/wp\/wp-json\/wp\/v2\/users\/20"}],"replies":[{"embeddable":true,"href":"http:\/\/theskepticalzone.com\/wp\/wp-json\/wp\/v2\/comments?post=4737"}],"version-history":[{"count":0,"href":"http:\/\/theskepticalzone.com\/wp\/wp-json\/wp\/v2\/posts\/4737\/revisions"}],"wp:attachment":[{"href":"http:\/\/theskepticalzone.com\/wp\/wp-json\/wp\/v2\/media?parent=4737"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/theskepticalzone.com\/wp\/wp-json\/wp\/v2\/categories?post=4737"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/theskepticalzone.com\/wp\/wp-json\/wp\/v2\/tags?post=4737"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}