"The pharyngula stage: the pharyngula is a vertebrate embryo that has assembled the outlines of the body plan. It has the key features of vertebrate morphology -- a post-anal tail, a notochord, a dorsal neural tube, a segmented musculature, and an array of branchial arches ("gill" arches). The major organs have begun to form."
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My previous contributions to the basic concepts in science collection were on gastrulation and neurulation, so let's add the next stage, and the one I named the blog after: the pharyngula.
First, though, a few general remarks on developmental stages. In some ways, these are somewhat arbitrary:…
Every 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…
I've been tinkering with a lovely software tool, the 3D Virtual Embryo, which you can down download from ANISEED (Ascidian Network of In Situ Expression and Embryological Data). Yes, you: it's free, it runs under Java, and you can get the source and versions compiled for Windows, Linux, and Mac OS…
The Institute for Creation Research is going on and on again about Haeckel and gill slits. It gets tiresome; I've explained so many times that Haeckel's theory was wrong and he skewed his drawings to fit his model, but that it really is true that human embryos have pharyngeal arches that are…