Lecture 17 - estimation really isnt perfect. (1) He only...

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Lecture 17 1) Ecdysis has evolved once for the molecular tree, twice for the morphological tree. 2) Spiders, centipedes, and millipedes are NOT insects. Insects have only 3 pairs of legs. 3) Insects are by far the most diverse group, over 1.6 million species and 1 million are insects. About 500,000 are beetles. a) They are the most dominant/numerous ANIMALS on earth today. b) Most widespread, occur in many diverse environments. 4) Terry Erwin – takes a rainforest tree, wraps it up, fumigates it, bug die and fall to the ground, he found 900 beetle species in one tree. a) 18% are host specific, only live on that type of tree b) In that environment, beetles represent 40% of all arthropods. c) With 50,000 species of tropical trees, there are about 30 million host specific arthropods there. i) He’s taken a lot of bold assumptions (only found 1.6 million species), so this
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Unformatted text preview: estimation really isnt perfect. (1) He only samples one tree, a lot of assumptions about host-specificity (that the host-specificity of beetles is the same as all arthropods). (2) He assumes that the single tree he sampled has the same host-specificity as all tropical trees. He only sampled one tree. 5) Insect body plan Head, thorax (3 segments each with a pair of legs), abdomen (around 11 segments, but not for all insects). a) Open circulatory system Does not carry oxygen, dorsal heart pumps blood to the dorsal artery from which blood is circulated through the internal cavity and goes to organ. 6) Cuticle is expandable, wings develop from the cuticle, it is often lined with waxes to prevent desiccation....
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This note was uploaded on 02/09/2012 for the course BIOL 104 taught by Professor Smith during the Spring '09 term at Arkansas State.

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