Submitted by Whats-Upvote t3_11cjb1s in Showerthoughts
lightknight7777 t1_ja4iida wrote
Reply to comment by DrInsomnia in For birds all sex is anal sex. by Whats-Upvote
That doesn't make it an anus. It's not.
Semantics is what words mean. Of course it's semantics.
DrInsomnia t1_ja4j8ck wrote
Yes. And a cloaca is an anus that has taken on additional functionality in some groups. In fact, in mammals the original mammalian ancestor likely had a cloaca, which split into separate openings (in some derived groups). But embryologically it all starts with the anus.
DrInsomnia t1_ja4jodn wrote
I should add that mammals are the outlier here, having subdivided these tasks into separate orifices. Most vertebrates have a single opening, derived from embryological anal opening, which does it all.
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