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PRESENTATION ORDER FOR MONDAY

PRESENTATION ORDER FOR MONDAY. (3%). (18%). (5%). (4%). (9%). (5%). (56%). numbers of described species of plants and animals. after: Groombridge, B. 1992. Global Biodiversity: Status of the Earth's Living Resources . London, Chapman & Hall. .

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PRESENTATION ORDER FOR MONDAY

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  1. PRESENTATION ORDER FOR MONDAY

  2. (3%) (18%) (5%) (4%) (9%) (5%) (56%) numbers of described species of plants and animals after: Groombridge, B. 1992. Global Biodiversity: Status of the Earth's Living Resources. London, Chapman & Hall.

  3. a description of the life of an organism, focusing on key events of significance to that organism's survival and/or reproduction the ways in which these "events of significance" are molded by natural selection, leading to differences among populations/species in life cycles, morphology, distribution etc. what's a "life history"? ...so what's "life history evolution"?

  4. Metazoa: Protostomes: Deuterostomes: Wray GA (2000) The evolution of embryonic patterning mechanisms in animals. Sem. Cell Dev. Biol.11: 385-393.

  5. Feeding and nonfeeding larvae Egg Feeding larva Juvenile Egg Nonfeeding larva Juvenile

  6. larva of the "paddle urchin" Colobocentrotus atratus (Oahu, Hawai'i) photo by J. Hodin

  7. juveniles of the sea urchin Diadema antillarum photo by J. Hodin

  8. the Australian sea urchins Heliocidaris erythrogramma and Heliocidaris tuberculata....and their larvae http://evodevo.uoregon.edu/ people/wilson.html ?? from: G.A. Wray (1995) Punctuated Evolution of Embryos.Science 267:1115-6

  9. Juvenile size is constrained in echinoderms, particularly in planktotrophic echinoids Echinoids (sea urchins, sand dollars) Asteroids (starfish) Juvenile diameter after metamorphosis (um) egg diameter (um) brooders (non- feeding) non-feeding larvae compiled from: Emlet et al. (1987) Echinoderm Studies 2: 55-136 feeding larvae

  10. Well, then, what's the difference? feeding larvae apparently need to feed to get a hormone necessary for metamorphosis - and this is the SAME hormone that frogs tadpoles produce as they're undergoing metamorphosis to the juvenile frog.... Is the only difference between feeding and non-feeding larvae that feeding larvae come from smaller eggs? NO! thyroid hormone (TH)!

  11. A sand dollar with a feeding larva and a large egg can complete metamorphosis in the absence of food, but ONLY if you treat the larvae with extra TH… 100um 100um with food starved with TH • Reduced juvenile size after metamorphosis • Able to complete metamorphosis with TH and no food • Accelerated development of adult structures with TH Leodia sexiesperforata - 210µm egg - a sand dollar from the NE Atlantic with a feeding larva

  12. OK, well then how do non-feeding larvae make a juvenile without feeding? hypothesis 1: they don't require TH hypothesis 2: they make it themselves hypothesis 3: mom packs it in the egg

  13. Non-feeding echinoid larvae can produce TH themselves! Starved larvae of the facultative feeding "sea biscuit" Clypeaster rosaeceus (Caribbean) show an inhibition of metamorphosis when treated with the TH synthesis inhibitor thiourea, and this effect increases with increased thiourea concentration TH contents increase throughout embryonic and larval development in the non-feeding sand dollar Peronella japonica (Japan) • T4 • T3 % completing metamorphosis 9 Saito et al., 1998 Heyland & Reitzl, in prep.

  14. so what does this all have to do with the evolution of life histories? internal production of TH appears to be required for non-feeding larval development to evolve it's possible that not all urchin larvae have equal potential to produce TH themselves, thus yielding evolutionary patterns in the evolution of life histories hormones seem to be important both for metamorphosis, and for evolutionary alterations in patterns of metamorphosis (non feeding larval development in some echinoids, larval reproduction in some insects, "direct development" in some frogs)

  15. larval reproduction in the gall midge Mycophila speyeri(Insecta: Diptera: Cecidomyiidae) FROM: Hodin & Riddiford (2000) Dev Genes Evol 210: 358–372

  16. A dredge off Otago Harbor, Dunedin, NZ photo by J. Hodin

  17. Echinoderms from off Otago Harbor, Dunedin, NZ photo by J. Hodin

  18. class Echinoidea class Asteroidea (sea urchins, sand dollars, sea biscuits) (starfish) PHYLUM ECHINODERMATA class Ophiuroidea M. Benjamin Cowan class Crinoidea class Holothuroidea (brittle stars, basket stars) Paddy Ryan (feather stars, sea lilies) (sea cucumbers) upper 2 photos by J. Hodin

  19. some factoids about echinoids.... • no "head" per se • nervous system: nerve ring with radial nerves • rigid dermal skeleton with mutable collagen; specialized nerves controlling lantern • miscellaneous specializations: spines, tube feet, pedicellaria, "Aristotle's lantern", much more rigid skeleton ("test") than other echinoderms • predators include sea otters, starfish, lobsters, birds, humans, octopods • approx. 1000 living species, all marine • triploblasts; five-fold symmetry as adults, bilateral as larvae • all are male-female • usually external fertilization, some brood • all adults are benthic • most are grazers, some are predators, deposit or suspension feeders • many have feeding larvae - pluteus http://www.microscopy-uk.org.uk/ mag/artjul00/urchin2.html http://virtual.yosemite.cc.ca.us/randerson/ Marine%20Invertebrates/aristotl.htm photo by J. Hodin

  20. sea urchin diversity Pacific Northwest sea urchins - Strongylocentrotus spp. paddle urchin (Colobocentrotus atratus) Hawai'ian sea urchins red pencil urchin (Heterocentrotus mammilatus) http://faculty.washington.edu/biermann/research.htm#top heart urchin (Meoma ventricosa) http://www.wetwebmedia.com/urchins.htm

  21. sand dollars are echinoids too! Dendraster excentricus South Alki Beach, photos by Eric Munger

  22. some factoids about asteroids.... • approx. 1800 living species, all marine • triploblasts; five-fold symmetry as adults, bilateral as larvae • almost all are male-female, a few hermaphrodites • usually external fertilization, some brood • all adults are benthic • most are predators, some are grazers, a few deposit or suspension feeders • stereotypical feeding larval forms are bipinnaria/brachiolaria - many species have modified and/or non-feeding larvae • no "head" per se • nervous system: nerve ring with radial nerves; "eyes" at the tips of the arms • rigid dermal skeleton with mutable collagen • miscellaneous specializations: tube feet (often modified depending on substrate type), eversible stomach, regeneration (larvae and adults!) • predators include fish, birds, BIG snails, crustaceans, sharks, sea otters (Vickery & Mcklintock, 2000) Jan Parmentier soft-bottom hard-bottom substrate substrate

  23. some factoids about ophiuroids.... • approx. 2000 living species, all marine • triploblasts; five-fold symmetry as adults, bilateral as larvae • almost all are male-female, a few hermaphrodites, some asexual • usually external fertilization, some brood • all adults are benthic • most are deposit and/or suspension feeders, some are scavengers or active predators • feeding larval form is a pluteus - many species have non-feeding larvae • no "head" per se • nervous system: nerve ring with radial nerves • rigid dermal skeleton with mutable collagen - less pronounced than in other echinoderms • miscellaneous specializations: muscular movement, autotomy as defense mechanism, regeneration (larvae and adults!), eyes!! • major predators are fish Gordon Hendler Joanna Aizenberg Ophiocoma wendtii Wim van Egmond Kerry Werry Nature 412, 819 - 822 (23 Aug 2001)

  24. some factoids about holothuroids.... • stereotypical feeding larval form is an auricularia larva - many species have non-feeding larvae • no "head" per se; vermiform; more tendency towards bilateral symmetry than other living echinoderms • nervous system: nerve ring (prominent around mouth) with radial nerves • dermal skeleton reduced to ossicles with mutable collagen; hydrostatic skeleton • miscellaneous specializations: feeding tentacles; can eject sticky cuvierian tubules when pissed; can eviscerate stomach when super pissed • major predators are starfish, stomatopods, humans • approx. 1200 living species, all marine • triploblasts; five-fold symmetry as adults, bilateral as larvae • most are male-female, a few simultaneous hermaphrodites; some asexual • internal or external fertilization, many brood • most adults are benthic; but there are a few holoplanktonic sea cucumbers!! • most are deposit or suspension feeders Sumaitt Putchakarn. Mike Reich Greg Wray www.emedicine.com/emerg/topic158.htm

  25. some factoids about crinoids.... • filter feeders • all have non-feeding larvae • no "head" per se • nervous system: nerve ring with radial nerves; aboral concentration unique among echinoids • dermal skeleton with mutable collagen • miscellaneous specializations: pinnules for feeding; cirri make a "holdfast" • major predators are starfish, stomatopods, humans • approx. 600 living species, all marine; were once incredibly abundant in the fossil record (5000 fossil species) • triploblasts; five-fold symmetry as adults, bilateral as larvae • all are male-female • internal or external fertilization, many brood • all adults are benthic; some can swim Hiroaki Nakano (dots indicate a ciliated band) www.ucmp. berkeley.edu Charles Messing Bather, 1900

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