Biology 3484A/B Lecture Notes - Lecture 13: Pterygota, Neontology, Hexapoda

• School: Western University
• Department: Biology
• Course: Biology 3484A/B
• Professor: Nina Zitani

Document Summary

Bilateria (cid:862)i(cid:374)se(cid:272)ts(cid:863) = (cid:272)o(cid:373)(cid:373)o(cid:374) (cid:374)a(cid:373)e for 6-legged arthropods. Insects are primary of secondary food source for 1000s of species (cid:862) if i(cid:374)se(cid:272)ts (cid:449)ere to (cid:448)a(cid:374)ish, the e(cid:374)(cid:448)iro(cid:374)(cid:373)e(cid:374)t (cid:449)ould (cid:272)ollapse i(cid:374)to (cid:272)haos. (cid:863) e. o. Hexapoda: three body regions (head, thorax, abdomen, three pairs legs and one pair antennae. Abdomen: major organs/reproduction: dominant arthropods/dominant group of organisms on land in terms of numbers of species, and biomass, almost 1 million described species, hyperdiverse taxon; mostly in tropical forests. First insects evolved from either millipede or crustacean-like ancestor (no wings) Synapomorphy: two pairs of wings attached to thorax: few taxa have character reversal (lost one or both pairs, thorax is highly specialized for flight. Thorax: large muscles to power legs and wings. Wings cannot be twisted and folded/ do not lie flat on top of abdomen. Synapomorphies: modified exoskeleton at base of wings, specialized thoracic muscles. **can twist and fold wings; lie flat over body when at rest.