development
pharyngula | January 13, 2006A reader sent in this little question:
Possible answers:
Well, what if McNuggets have souls, huh? What do you think of that, smart guy?
Neither have souls!
"Good" and "McNuggets" in the same sentence?
Let's have a taste test and find out.
pharyngula | January 12, 2006Every biology student gets introduced to the chordates with a list of their distinctive characteristics: they have a notochord, a dorsal hollow nerve cord, gill slits, and a post-anal tail. The embryonic stage in which we express all of these features is called the pharyngula stage—it's often also the only stage at which we have them. We terrestrial vertebrates seal off those pharyngeal openings as we develop, while sea squirts throw away their brains as an adult.
The chordate phylum has all four of those traits, but there is another extremely interesting phylum that has some of them, the…