# Bones evolving in fish **URL:** \ **Category:** Great Debates\ **Created:** [April 12, 2003, 10:27pm UTC](https://boards.straightdope.com/t/bones-evolving-in-fish/168336 "2003-04-12T22:27:37Z")\ **Posts on this page:** 7\ **Page:** 1
**Author:** ![Fuel](https://avatars.discourse-cdn.com/v4/letter/f/df705f/32.png) [@Fuel](https://boards.straightdope.com/u/Fuel)\ **Post date:** [April 12, 2003, 10:27pm UTC](https://boards.straightdope.com/t/bones-evolving-in-fish/168336/1 "2003-04-12T22:27:37Z")
Why did fish evolve bones? ---
**Author:** ![hardcore](https://avatars.discourse-cdn.com/v4/letter/h/b5a626/32.png) [@hardcore](https://boards.straightdope.com/u/hardcore)\ **Post date:** [April 12, 2003, 10:51pm UTC](https://boards.straightdope.com/t/bones-evolving-in-fish/168336/2 "2003-04-12T22:51:07Z")
It yielded a survival advantage, allowing them to be more successful at passing on their genes. ---
**Author:** ![Fuel](https://avatars.discourse-cdn.com/v4/letter/f/df705f/32.png) [@Fuel](https://boards.straightdope.com/u/Fuel)\ **Post date:** [April 13, 2003, 2:33am UTC](https://boards.straightdope.com/t/bones-evolving-in-fish/168336/3 "2003-04-13T02:33:43Z")
Building bones allowed them to pass on genes better… how? I don’t see the connection, but I am not a scientist either. Could you elaborate a little? ---
**Author:** ![Splanky](https://avatars.discourse-cdn.com/v4/letter/s/b2d939/32.png) [@Splanky](https://boards.straightdope.com/u/Splanky)\ **Post date:** [April 13, 2003, 2:42am UTC](https://boards.straightdope.com/t/bones-evolving-in-fish/168336/4 "2003-04-13T02:42:03Z")
You’re saying that fish didn’t originally have bones? They were just blobs drifting in the ocean with no shape? ---
**Author:** ![Scylla](https://avatars.discourse-cdn.com/v4/letter/s/a5b964/32.png) [@Scylla](https://boards.straightdope.com/u/Scylla)\ **Post date:** [April 13, 2003, 2:46am UTC](https://boards.straightdope.com/t/bones-evolving-in-fish/168336/5 "2003-04-13T02:46:41Z")
Sure. A rigid surface like bone or cartilage creates something called moment arm in the muscles that attach to it. It creates greater leverage, strength/weight, and efficiency. Moment arm is one of the reasons why a golf ball goes further when you hit with a club than when you throw it. Similarly a fish with a rigid structure that muscles can act on, lets it move the water faster than a boneless fish, a clear survival advantage. You can paddle a boat better with an oar than with a noodle. ---
**Author:** ![Scylla](https://avatars.discourse-cdn.com/v4/letter/s/a5b964/32.png) [@Scylla](https://boards.straightdope.com/u/Scylla)\ **Post date:** [April 13, 2003, 2:52am UTC](https://boards.straightdope.com/t/bones-evolving-in-fish/168336/6 "2003-04-13T02:52:57Z")
> [@](#): > > \*Originally posted by Splanky \* > \*\*You’re saying that fish didn’t originally have bones? They were just blobs drifting in the ocean with no shape? \*\* jellyfish ---
**Author:** ![Terrifel](https://avatars.discourse-cdn.com/v4/letter/t/c68b51/32.png) [@Terrifel](https://boards.straightdope.com/u/Terrifel)\ **Post date:** [April 13, 2003, 3:21am UTC](https://boards.straightdope.com/t/bones-evolving-in-fish/168336/7 "2003-04-13T03:21:28Z")
Bones provide protection for internal organs, anchor points for musculature, and support for bodily structures. The first skeletal structures were probably made up of cartilage, as seen in primitive jawless fish such as lampreys. Some fish, such as sharks and rays, still get along fine with a largely cartilaginous skeleton. Bony fish, so called because they have calcified bones, probably derive the greatest advantage from the increased strength and shear resistance of bone, which permits greater speed and maneuverability. Cartilage is lighter, but more prone to damage under stress. In some fishes, bone has also been incorporated into scales and dermal plates for added protection.