|MadSci Network: Zoology|
You point out a common problem of most basic Biology Texts. Many books hardly ever go into detail about the important reasons of why the coelom is important. Actually, you are better off looking through an Invertebrate Biology text book, as body cavities are heavily discussed. The body cavity has many uses: 1) The coelom cushons organs from internal injury. This is because they are not directly attached to the outer body. 2) In soft-bodied animals (earth worms) the fluid filled coelom functions (when under pressure from muscles) as a hydrostatic skelton for movement. 3) The coelom helps enable the internal organs to grow and move independently of the outer body wall. Imagine if you could see the peristaltic action of your intestines if you did not have a body cavity! Ick! Basically, if the internal organs were not separated from the outer body surface you'd have a tough time moving and bending your body. This is because any movement by your external body would then distort your internal organs, perhaps causing problems. -Hope this helps! -Mike References: Campbell & Reece (2002) 'Biology (6th Edition)" Benjamin Cummings, San Fransico. Page 638 Kingdom Animalia: http://www.lander.edu/rsfox/112anim.html
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