Internal Fluid Transport in Early Animals
~550 Million Years Ago (+/- 25 million)
Diffusion and body-cavity circulation
As animals grew larger, simple diffusion was no longer enough, so internal fluid movement evolved.
As multicellular animals grew larger, simple diffusion became insufficient to move nutrients and remove waste. Early animals evolved internal fluid movement within body cavities, allowing nutrients to circulate beyond direct cell-to-cell contact.
In the earliest multicellular animals, every cell could no longer rely on direct contact with the outside world. Internal fluid transport through body cavities was a major step forward, helping larger bodies move nutrients and remove waste before the evolution of fully developed blood vessels and hearts.
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Scale changes the problem. As early animals grew larger, diffusion alone could no longer move nutrients and waste efficiently, so new internal transport systems evolved.
Subject: Scale and Complexity.
A solution that works perfectly at one scale may fail at another. Bigger bodies created new physical constraints, and evolution responded with new systems. This is useful far beyond biology: when situations grow in size or complexity, do not assume the old solution will keep working. Reevaluate the problem.
was first published on TST 8 months ago.
