Ch 33 - Invertebrates (PART 2 of 2)(1 slide per page)-1

Subphylum hexapoda six feet class insecta 3 smaller

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Unformatted text preview: m Myriapoda (“many feet”) Unspecialized: many segments, most identical Class Diplopoda (“double foot”): millipedes • Rounded body (head/trunk) • Detritovores • 2 pairs legs / segment • Some w/ cyanide on exoskeleton 114 4. Subphylum Hexapoda “Six Feet” Class Insecta + 3 smaller classes • Mostly terrestrial • 3 body regions (head/thorax/abdomen) • 3 prs appendages all on thorax • 0-2 pairs of wings all on thorax See Figure 33.35 (Campbell et al) 115 Several complex organ systems • Circulatory system (will discuss in later chapter) • Excretory system (will discuss in later chapter) • Nervous system • 2 ventral nerve cords, brain 116 Respiratory system: spiracles (openings) & tracheae (tubes) Spiracles can open/close Trachea: branched chitin-lined tubes take oxygen directly to cells. Reproduction 117 • Fertilization internal • Usually lay undeveloped eggs • Some eggs develop internally & hatch upon laying • Some develop internally w/o egg • 2 types of metamorphosis A. Incomplete - Younger stages (nymphs) resemble adults. Final ecydysis (molt): Adult, full size, wings and sexually mature Usually: Juveniles= Non-winged FEEDING STAGE Adults = winged DISPERSAL & REPRODUCTIVE STAGE B. Complete - Larval stages completely different in form from adult: Adult Egg Larva Pupa 118 Insect Phylogeny ~ 1 million described species > 74% of animal species / ~20% of all species • Estimated to be ~6-10 million species ~30 orders of insects • Coleoptera (Beetles) (~35%) • Flies (Diptera)(~10%) • Butterflies, moths (Lepidoptera) (~10%) ...
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