32_Ward_Arthropoda+2+Outline

32_Ward_Arthropoda+2+Outline - BIS2C W2011 Arthropoda Part...

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BIS2C W2011 Lecture 32 (4 March 2011) 1 Arthropoda Part 2 Chelicerata Sea spiders (Pycnogonida) are a third kind of chelicerate. Hexapoda: most diverse subgroup within the Arthropoda ~1,000,000 described species three insect orders (Lepidoptera, Hymenoptera, Coleoptera) contain half of all described animal species Features of Hexapoda (insects and allies) three tagmata: head, thorax and abdomen one pair of antennae three pairs of legs respiration by tracheae originally: mandibulate mouthparts Wings evolved within the insects. How did insect wings evolve? 1) From what structures did insect wings evolve? Gene expression studies point to dorsal appendages at the base of the legs. Possibly gills in a larval aquatic stage, modified in adults for other purposes. 2) What was the function of the pro-wings (before flight)? Hypothesized functions include: thermoregulation (basking in sun), gliding in the air, or sailing along the water surface.
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BIS2C W2011 Lecture 32 (4 March 2011)
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This note was uploaded on 03/09/2011 for the course BIS 2 taught by Professor Coolprof during the Spring '11 term at Bank Street College of Education.

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32_Ward_Arthropoda+2+Outline - BIS2C W2011 Arthropoda Part...

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