Darwin, Earthworms & Circadian Rhythms: A Fertile Field for Science Fair Experiments

摘要

The earthworm's relatively simple digestive system, consisting of a mouth, pharynx, esophagus, crop, gizzard, and intestine, enables it to grind vegetable matter and other stray material that it ingests to produce the clay-like manure castings egested from its anus and deposited on the ground's surface. [...] the Phylum Annelida has many thousands of species, all of which have segmented, or more correctly, metamerie, bodies.