Ward_Lect33A_Echinodermata_ppt

Ward_Lect33A_Echinodermata_ppt - BIS2C Winter 2010 (Ward)...

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Unformatted text preview: BIS2C Winter 2010 (Ward) Lecture 33. Echinodermata Todays lecture (8 March) Arthropoda (Hexapoda): concluded introduction to Deuterostomes Echinodermata major features of echinoderms echinoderm diversity Wednesday Chordates, Part 1 Other trends in insect evolution Coevolution with flowering plants Insect orders (major clades) arose in Permian (260 mya) or earlier Angiosperms originated about 150 mya Thus, coevolution with flowering plants had an effect on diversification within insect orders, not on the origin of major clades Other trends in insect evolution Coevolution with flowering plants Recall the method of multiple sister-group comparisons for testing effects of different factors on rates of diversification . For example, latex- and resin-bearing plants have more species, on average, than sister taxa without these features. Similarly, clades of phytophagous (plant-feeding) insects have been compared to sister taxa that are not plant feeders. Guess which ones show higher net diversification? Other trends in insect evolution Coevolution with flowering plants On average, plant-feeding insects are more species-rich than sister taxa that do not feed on plants (predators or scavengers). Coevolution with flowering plants On average, plant-feeding insects are more species-rich than sister taxa that do not feed on plants (predators or scavengers). What are likely explanations for this pattern? 1. Predators and scavengers have lower extinction rates. 2. Clades of plant-feeding species tend to be older than their non-plant-feeding sister groups. 3. Plant-feeding insects have fewer natural enemies. 4. Plant-feeding insects can specialize more than predators and scavengers. Other trends in insect evolution Social insects Eusocial insects live in colonies with division of labor : some individuals reproduce (queen, male), but most individuals belong to a non-reproductive worker caste . Other trends in insect evolution Social insects Eusocial insects live in colonies with division of labor : some individuals reproduce (queen, male), but most individuals belong to a non-reproductive worker caste . Major eusocial insects are (1) termites, (2) ants, (3) some bees and (4) some wasps. Other trends in insect evolution Social insects Eusocial insects live in colonies with division of labor : some individuals reproduce (queen, male), but most individuals belong to a non-reproductive worker caste ....
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Ward_Lect33A_Echinodermata_ppt - BIS2C Winter 2010 (Ward)...

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