{"id":2125,"date":"2005-02-04T21:09:00","date_gmt":"2005-02-05T01:09:00","guid":{"rendered":"http:\/\/www.meehawl.com\/Blogfiles-wp\/?p=2125"},"modified":"2005-02-04T21:09:00","modified_gmt":"2005-02-05T01:09:00","slug":"aliens-amongst-us","status":"publish","type":"post","link":"https:\/\/www.meehawl.com\/Blogfiles\/2005\/02\/04\/21\/09\/aliens-amongst-us\/","title":{"rendered":"Aliens Amongst Us"},"content":{"rendered":"

I was thinking about the biological dogma that cephalisation<\/a> can only occur
\nwithin bilaterally symmetric animals (Bilateria<\/span><\/a>). It seems to me that a bilateral
\nsymmetry would put evolutionary pressure on such animals to evolve
\ncephalization (and hence eyes\/sensors and response cells) because they
\nare on “rails”, but that the evolution of a rapid, focussed
\nstimulus-response within a radially symmetric animal would be less
\nlikely, but would still happen, given enough time and stimulus. Therefore *more* bilateria should exhibit cephalisation and developed brains (and in fact that is overwhelmingly true!) but that development of complex environmental processing adaptations analogous to brains could still evolve within Radiata<\/span><\/a>. Of course, the proportion of radially symmetric<\/a> animals that develop advanced mentation will be less than bilaterally symmetric animals, but it’s still happen. Maybe there *are* massive intelligent medusae on Jupiter<\/a>?<\/p>\n

Then I found the box jellies<\/a>, Cubozoa<\/span><\/a>. These things are cool. They are a class of “hunting” Cnidaria<\/a><\/span> (jellyfish!) that have evolved complex eyes<\/a> and rapid, directed locomotion<\/a> (sometimes lunging up to 6 feet in a second to sting prey).<\/p>\n

There’s is a close-up of these multi-eyed predators<\/a>:<\/p>\n

\"Rhopalium<\/a><\/p>\n

Here’s the mystery. The box jellies manage to use complex eyes (corneas, lenses, retinas), and directed hunting tactics, yet have no discernable brain or, indeed, a nervous column. They have a ring of nerve cells around their periphery and this seems to be sufficient to build models of their environment.<\/p>\n

And along the way, I did find out where Cameron got his idea for the Abyss<\/span> aliens<\/a>: the comb jellies, or Ctenophora<\/a><\/span>. They are free-swimming, aggressive predators<\/a>, with a curiously streamlined radial symmetry<\/a>:<\/p>\n

\"Red
\n\"Red<\/p>\n","protected":false},"excerpt":{"rendered":"

I was thinking about the biological dogma that cephalisation can only occur within bilaterally symmetric animals (Bilateria). It seems to me that a bilateral symmetry would put evolutionary pressure on such animals to evolve...<\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_jetpack_memberships_contains_paid_content":false,"footnotes":""},"categories":[1],"tags":[],"class_list":["post-2125","post","type-post","status-publish","format-standard","hentry","category-uncategorized"],"aioseo_notices":[],"jetpack_featured_media_url":"","jetpack-related-posts":[],"jetpack_sharing_enabled":true,"_links":{"self":[{"href":"https:\/\/www.meehawl.com\/Blogfiles\/wp-json\/wp\/v2\/posts\/2125","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.meehawl.com\/Blogfiles\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.meehawl.com\/Blogfiles\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.meehawl.com\/Blogfiles\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.meehawl.com\/Blogfiles\/wp-json\/wp\/v2\/comments?post=2125"}],"version-history":[{"count":0,"href":"https:\/\/www.meehawl.com\/Blogfiles\/wp-json\/wp\/v2\/posts\/2125\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.meehawl.com\/Blogfiles\/wp-json\/wp\/v2\/media?parent=2125"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.meehawl.com\/Blogfiles\/wp-json\/wp\/v2\/categories?post=2125"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.meehawl.com\/Blogfiles\/wp-json\/wp\/v2\/tags?post=2125"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}