Domain Eukarya Kingdom Rhodophyta/Biliphyta? Phylum Rhodophyta

The Organism as a Unit of Life Looking Back at Bio 115 The Organism as a Unit of Life Cellular Structure (cell = unit of life)…one or many! Metabolism = Homeostasis (PSN, Resp, N2fix, ferment, etc.) Growth = irreversible change in size Reproduction…failure = extinction Acclimatization-short term responses = behavior Adaptation-long term responses = evolution

Multicellular Animals Shifting Kingdoms Lumpers Splitters Plantae Protista Rhodophyta 2 3 5 6 8 Bacteria Archaebacteria Archezoans Euglenoids Chrysophytes Green Algae Brown Algae Red algae Slime Molds True Fungi Bryophytes Tracheophytes Protozoans Myxozoans Multicellular Animals

How Many Kingdoms? Extant 8 5 3 Extinct 2 Long Time with 1 Archaebacteria Archezoans Multicellular Animals Protozoans Green Algae Bryophytes Tracheophytes Slime Molds Myxozoans True Fungi Bacteria Euglenoids Chrysophytes Brown Algae Red algae 8 5 3 Extinct 2 1 Long Time with Prokaryotes only Original Cell

Rhodophyta Photosynthetic, mostly marine red algae Odd features Body multicellular, supported by water, so simple thallus Thallus attached to substrate by holdfast Rarely pelagic (floating) Chloroplasts have three membranes (secondary endosymbiont) Photosynthetic pigments: chlorophyll a, phycoerythrin, phycocyanin…colors can be red, brown, purple, blue, green, blackish! Storage materials: floridean starch in cytosol (-1,4-glycan) Wall polysaccharides: cellulose and agar or carrageenan No flagella, so centriole missing Gametangia: spermatangia (male) and carpogonium (female) Some species encrust with calcium carbonate…contribute to reefs 4000 species

http://www.dennerle.de/images/pflanzen/algen/bartmic.gif Compsopogon Here are some of the example red algae some of these you should have observed in laboratory. http://www.biology.lsa.umich.edu/courses/bio458/Caloglossa.jpg Caloglossa http://www.cibnor.org/colecciones/malgas/img/poc.jpg Porphyridium http://www.bio.utexas.edu/research/utex/photogallery/Callithamnion_baileyi_lb2306.jpg Callithamnion

Porphyridium Cell Wall Cell Membrane Mitochondrion Nucleus http://www.bio.mtu.edu/the_wall/phycodisc/RHODOPHYTA/gfx/PORPHYRIDIUM_UNICELL.jpg Cell Wall Cell Membrane Mitochondrion Nucleus Stellate Chloroplast Floridean Starch Vacuole

Polysiphonia nigrescens Polysiphonia nigrescens http://www.com.univ-mrs.fr/IRD/atollpol/ecorecat/images/polyser.jpg Polysiphonia nigrescens Polysiphonia nigrescens benthic (attached) filamentous common on New England rocky coast http://www.biology.lsa.umich.edu/courses/bio458/Polysiphonia_tetraspores.jpg 2N tetrasporophyte tetrasporangium tetraspore (meiospore)

Polysiphonia nigrescens Tetraspore (meiospore) germinates into isomorphic homothallic gametophyte (1N) thallus Male branches near the tops of the plants produce spermatangia Female branches near the bottom of the thallus produce carpogonia http://www.microscopy-uk.net/mag/imgmar99/polys7c.jpg

Polysiphonia nigrescens http://www.microscopy-uk.org.uk/micropolitan/ marine/algae/polysiphonia%20male.jpg Polysiphonia nigrescens Tetraspore (meiospore) germinates into isomorphic thallus Male branches produce spermatangia releasing spermatia Female branches produce carpogonium with trichogyne. Trichogyne receives spermatium (no flagellum!) spermatium trichogyne http://www.biology.lsa.umich.edu/courses/bio458/Polysiphonia_female.jpg

Polysiphonia nigrescens http://www.microscopy-uk.net/mag/imgmar99/polys11b.jpg The 2N zygote develops inside the cystocarp attached to the gametophyte (1N) thallus. The cystocarps expand and mature into carposporangia Carposporangia release diploid carpospores which then germinate into diploid tetrasporophytes. http://www.microscopy-uk.org.uk/micropolitan/marine/algae/Polysiphonia%20nigrescens450.jpg http://www.microscopy-uk.net/mag/imgmar99/polys3.jpg

Polysiphonia Life Cycle syngamy Note: See previous slides for photo credits! spermatangium syngamy gametes (produced by mitosis) zygote (inside cystocarp) Carposporophyte (inside cystocarp) spermatium (released to water) 1N 2N carpogonium carpospore (released to water settles to substrate grows by mitosis) trichogyne cystocarp Tetrasporophyte Gametophyte isomorphic homothallic tetrasporangium tetrasporocyte tetraspore (released to water settles to substrate grows by mitosis) meiosis