BIOL 211 Lecture Notes - Lecture 6: Pinworm Infection, Trichinella Spiralis, Circulatory System
28 Sep 2017
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**-shedding of exoskeleton during growth: phylum nematoda (roundworms) 25,000 species names, may be over a million total. Most species have separate male + female systems. Trichinella spiralis> cause of trichinosis> acquired by eating undercooked meat. Pinworms> enterobius vermicularis> live in large intestines of humans. Estimated to be 1 billion billion 10^18 to be present on earth. Over 1. 1 million species named> most diverse, mostly insects. Organs specialized for respiration (gas exchange)- gills, book lungs, tracheal system. Trilobites>common in paleozoic era but disappeared in the permian mass extinction about. 4 main extant groups> chelicerates, myriapods, insects, and. Do not have chewing mouth parts, have anterior-most appendages (chelicerae) either pincers or fangs. Large number of walking legs 2 pairs per segment. Produces and secrete toxic materials to discourage potential predators. Have poison claws to aid in capture of prey and in defense. One pair of antennae>various functions> most common is detecting chemicals. ***-more species than all the other groups of organisms combined.
