Hank discusses the process by which organisms grow and develop, maintaining that, in the end, we're all just tubes.

Chapters:
1) Zygote
2) Morula
3) Blastula
4) Radial Symmetry
5) Bilateral Symmetry
6) Gastrulation
7) Blastopore
8) Gastrula
9) Protostomes & Deuterostomes
10) Germ Layers
a) Diploblastic
b) Triploblastic
11) Biolography

Biology is designed for multi-semester biology courses for science majors. It is grounded on an evolutionary basis and includes exciting features that highlight careers in the biological sciences and everyday applications of the concepts at hand. To meet the needs of today’s instructors and students, some content has been strategically condensed while maintaining the overall scope and coverage of traditional texts for this course. Instructors can customize the book, adapting it to the approach that works best in their classroom. Biology also includes an innovative art program that incorporates critical thinking and clicker questions to help students understand—and apply—key concepts.

By the end of this section, you will be able to:Discuss how fertilization occursExplain how the embryo forms from the zygoteDiscuss the role of cleavage and gastrulation in animal development

Gastrulation is the process of forming the three germ layers; ectoderm, mesoderm and endoderm. It is achieved through a series of highly coordinated cell movements. Cells that will form the endodermal and mesodermal organs are brought inside the embryo, whilst cells that will form ectoderm move to spread out over the outside of the embryo.

This resource is a video abstract of a research paper created by Research Square on behalf of its authors. It provides a synopsis that's easy to understand, and can be used to introduce the topics it covers to students, researchers, and the general public. The video's transcript is also provided in full, with a portion provided below for preview:

"During epithelial-mesenchymal transition (EMT), epithelial cells lose their polarity and their cell-cell connections to become mobile, in part via transcription factor (TF) activation. EMT and its reverse process, MET, are critical for tissue development in embryos, and EMT enables wound healing during adulthood, but EMT is also how cancer cells metastasize. Live imaging of animal embryos can yield important insights into these key processes. For example, FGF and actomyosin have been found to regulate intercellular adherens junction (AJ) remodeling during EMT in fruit flies. In addition, in zebrafish embryos, the planar cell polarity (PCP) protein pk1 ensures proper EMT of neural crest cells (NCCs), and cadherin 6 ultimately regulates NCC migration..."

The rest of the transcript, along with a link to the research itself, is available on the resource itself.