PennyBright
Posts: 78
Joined: May 2006
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| Quote (Ichthyic @ June 12 2007,17:23) | | Quote (JohnW @ June 12 2007,16:48) |
Speaking as a lay person (and expecting a slapping from Ichthyic if I've got this wrong): "Fish" is not a very helpful term in taxonomy, and while cartilaginous fish like sharks and rays and bony fish like most of the others share a common ancestor, they've been separate groups for an awfully long time. You and I are more closely related to a mackerel than Ichthy's toothy friend is. So it's not surprising that sharks look so different. |
yes and no.
even ichthyologists still group both chondrichthians (cartiliginous) and osteichthians (bony fish) under the greater heading of "fish".
but, yes, they did indeed separate hundreds of millions of years ago, and while sharks really haven't changed tremendously since (and not much at all in say, the last 140 million years or so), bony fish have tremendous radiation; around 30 thousand species worth at last count.
morphologically, a typical shark and a typical bony fish do share quite a number of features still, but you indeed could make a good argument that even morphologically, a human would be far closer to a bony fish than a cartilaginous one. |
This is why I hang out here. Straightforward informative dialog about things that are interesting. I think I've learned more about everything lurking around you EvC folks then I ever did in school.
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Conversation should be pleasant without scurrility, witty without affectation, free without indecency, learned without conceitedness, novel without falsehood. - Shakespeare (reputedly)
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