Chapter 43 Lecture Enrichment Ideas
It is difficult to discuss the digestive systems of organisms meaningfully without an awareness of their lifestyle, habitat, etc. Explicating the complete and incomplete guts, and continuous and discontinuous feeders is much easier with visual slides or videotapes showing the organisms in action.
Describe the differences in teeth and digestive tracts among mammalian omnivores, herbivores, and carnivores. For fossil animals, sometimes the only evidence paleontologists have to deduce the life history of organisms is their dentition.
Comparing cnidaria and planaria to earthworms and insects, describe the increased need for separation and sophistication of the digestive, respiratory, and circulatory systems. Note that parasitic forms may often simplify from their complex ancestors.
Compare the earthworm's stomach, which is divided into crop and gizzard, to both the cow's stomach, with four separate areas to hold and digest food, and the simpler stomach of a human or a cat. Ask students why these specializations are related to diet.
Most students will be familiar with vitamins and other supplements. This is an opportunity to extend discussion into the science necessary to establish minimum daily requirements, genuine bioactivity, and solid guidelines to avoid deficiency or overdose.
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