{"content":{"sharePage":{"page":0,"digests":[{"id":"40936973","dateCreated":"1311157510","smartDate":"Jul 20, 2011","userCreated":{"username":"Angela_Schneider","url":"https:\/\/www.wikispaces.com\/user\/view\/Angela_Schneider","imageUrl":"https:\/\/www.wikispaces.com\/user\/pic\/1311637336\/Angela_Schneider-lg.jpg"},"monitored":false,"locked":false,"links":{"self":"https:\/\/biologyunit2-tsc.wikispaces.com\/share\/view\/40936973"},"dateDigested":1531983316,"startDate":null,"sharedType":"discussion","title":"Useless organs","description":"Living things can have the remnants of organs that are no-longer useful as a result of evolution.<br \/>\nOne example is outlined below.  I LOVE this example.  On the tips of of our ears humans often have a point of cartilage.  This is left over from when our ancestors have floppy ears like a dog.<br \/>\n<br \/>\nCute don't you think?<br \/>\n<br \/>\n'Around the sixth week of gestation, six swellings of tissue called the hillocks of Hiss arise around the area that will form the ear canal. These eventually coalesce to form the outer ear. Darwin's point, or tubercle, is a minor malformation of the junction of the fourth and fifth hillocks of Hiss. It is found in a substantial minority of people and takes the form of a cartilaginous node or bump on the rim of their outer ear, which is thought to be the vestige of a joint that allowed the top part of the ancestral ear to swivel or flop down over the opening to the ear.<br \/>\n<br \/>\nTechnically considered a congenital defect, Darwin's point does no harm and is surgically removed for cosmetic reasons only. However, the genetics behind it tells an interesting tale, says plastic surgeon Anthony Sclafani of the New York Eye and Ear Infirmary in New York City. The trait is passed on according to an autosomal dominant pattern, meaning that a child need only inherit one copy of the gene responsible to have Darwin's point. That suggests that at one time it was useful. However, it also has variable penetration, meaning that you won't necessarily have the trait even if you inherit the gene. &quot;The variable penetration reflects the fact that it is no longer advantageous,&quot; Sclafani says.'<br \/>\n<br \/>\nFrom New Scientist- read the full article by clicking on the link below.<br \/>\n<br \/>\n[<!-- ws:start:WikiTextUrlRule:11:http:\/\/www.newscientist.com\/article\/dn13927-five-things-humans-no-longer-need.html --><a class=\"wiki_link_ext\" href=\"http:\/\/www.newscientist.com\/article\/dn13927-five-things-humans-no-longer-need.html\" rel=\"nofollow\">http:\/\/www.newscientist.com\/article\/dn13927-five-things-humans-no-longer-need.html<\/a><!-- ws:end:WikiTextUrlRule:11 -->]","replyPages":[{"page":0,"digests":[],"more":0}]}],"more":false},"comments":[]},"http":{"code":200,"status":"OK"},"redirectUrl":null,"javascript":null,"notices":{"warning":[],"error":[],"info":[],"success":[]}}