{"id":158,"date":"2004-07-13T19:37:19","date_gmt":"2004-07-13T19:37:19","guid":{"rendered":"http:\/\/idiolect.truth.posiweb.net\/notes\/?p=158"},"modified":"2004-07-13T19:37:19","modified_gmt":"2004-07-13T19:37:19","slug":"tunicates","status":"publish","type":"post","link":"https:\/\/idiolect.org.uk\/notes\/2004\/07\/13\/tunicates\/","title":{"rendered":"Tunicates"},"content":{"rendered":"<p align=\"center\"><a href=\"http:\/\/www.ucmp.berkeley.edu\/chordata\/urochordata.html\"><img data-recalc-dims=\"1\" decoding=\"async\" src=\"https:\/\/i0.wp.com\/www.ucmp.berkeley.edu\/chordata\/urochordata.gif?w=580\"><\/a><\/p>\n<p>The young sea squirt swims the oceans. When it finds a comfortable rock to settle down on it attaches to it by the head and proceeds to digest its own brain &#8211; a brain which would be of no further use during an uneventful future of filter-feeding.<\/p>\n<p>Sea Squirts, aka tunicates, also aka urochordata, are more than just a curio from marine biology. Sea squirts are more closely related to humans than any other invertebrate group &#8211; evolutionary biologists reckon that they resemble the ancient last common ancestors of all vertebrates.<\/p>\n<p>The brains they have in the larval form are really just a rod of nerve cells, a notochord. But it&#8217;s this notochord, found in its most primitive form in the sea squirts, which defines the phylum to which all birds, fishes and mammals belong. We humans could, ultimately, be just a development on the larval form of these slimy plankton eaters.<\/p>\n<p>Nicol suggested to me that this means there might be a genetic switch which could still be flipped in humans, and would give us a strong urge to press our heads to the nearest rock face, digest our brains and move no more.<\/p>\n<p>I think maybe it&#8217;s already happened, except that the switch is memetic, not genetic. The rock is a sofa and the digestive juices responsible for atrophying our brains are the emissions from the TV.<\/p>\n<p>An additional curious note about <a href=\"http:\/\/en.wikipedia.org\/wiki\/Tunicata\">tunicates<\/a> is that they use a rare metal, vanadium, to bind oxygen in their blood, rather than iron (like humans) or copper (like squid). What this means for the sofa\/TV\/brain digestion analogy I don&#8217;t know.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>The young sea squirt swims the oceans. When it finds a comfortable rock to settle down on it attaches to it by the head and proceeds to digest its own brain &#8211; a brain which would be of no further use during an uneventful future of filter-feeding. Sea Squirts, aka tunicates, also aka urochordata, are [&hellip;]<\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"jetpack_post_was_ever_published":false,"_jetpack_newsletter_access":"","_jetpack_dont_email_post_to_subs":false,"_jetpack_newsletter_tier_id":0,"_jetpack_memberships_contains_paywalled_content":false,"_jetpack_memberships_contains_paid_content":false,"footnotes":"","jetpack_publicize_message":"","jetpack_publicize_feature_enabled":true,"jetpack_social_post_already_shared":false,"jetpack_social_options":{"image_generator_settings":{"template":"highway","enabled":false},"version":2}},"categories":[9],"tags":[],"class_list":["post-158","post","type-post","status-publish","format-standard","hentry","category-science"],"jetpack_publicize_connections":[],"jetpack_featured_media_url":"","jetpack_sharing_enabled":true,"jetpack_shortlink":"https:\/\/wp.me\/p5KQtW-2y","jetpack-related-posts":[],"_links":{"self":[{"href":"https:\/\/idiolect.org.uk\/notes\/wp-json\/wp\/v2\/posts\/158"}],"collection":[{"href":"https:\/\/idiolect.org.uk\/notes\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/idiolect.org.uk\/notes\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/idiolect.org.uk\/notes\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/idiolect.org.uk\/notes\/wp-json\/wp\/v2\/comments?post=158"}],"version-history":[{"count":0,"href":"https:\/\/idiolect.org.uk\/notes\/wp-json\/wp\/v2\/posts\/158\/revisions"}],"wp:attachment":[{"href":"https:\/\/idiolect.org.uk\/notes\/wp-json\/wp\/v2\/media?parent=158"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/idiolect.org.uk\/notes\/wp-json\/wp\/v2\/categories?post=158"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/idiolect.org.uk\/notes\/wp-json\/wp\/v2\/tags?post=158"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}