✅ Animal Anatomy

How this section is organized

IBO/USABO “Animal Anatomy” is not a zoology-wide survey of every phylum in equal depth — it’s overwhelmingly a human anatomy course on the structural side, extended by comparison to other vertebrates, with a lighter structural survey of the wider animal kingdom on top. This section is weighted accordingly, roughly 5 : 3 : 2:

• Human Anatomy — the densest tier, covering human organ-system structure (histology, named cell types, mechanism) in the depth actually tested. Originally planned as 5 pages, it’s split into 10 system-specific pages here — each Human page proved too dense for one system to share a page with another at full depth (compare, for instance, the single-page treatment of Skeletal+Integumentary against the now-separate Skeletal and Integumentary pages). The “5” in the ratio still refers to five systems worth of depth, now spread across more, shorter pages rather than fewer, longer ones.
• Vertebrate Anatomy (3 pages) — comparative, explicitly framed against the human baseline above.
• Animal Kingdom Anatomy (2 pages) — a lighter structural survey of invertebrate body plans.

Start with Body Plans & Foundational Concepts — every page below assumes its vocabulary (symmetry, tissue histology, germ layers, coelom types, cleavage patterns).

Human Anatomy

Vertebrate Anatomy

Animal Kingdom Anatomy