1 General Introduction and Characterization of the Marine Brown Algae: Part I Notes by Naomi Phillips Arcadia University Edited by Suzanne Fredericq University of Louisiana at Lafayette and Brian Wysor Roger Williams University

2 *Primarily marine class with 19 orders, >50 families, 270+ genera, 2500 species *All are multicellular *Range from simple filamentous forms to large complex plants (kelps) Brown Algae: General

3 *Rich in terms of biodiversity *Inhabiting great array of habitats habitats *Critical primary producers in pelagic and coastal environments pelagic and coastal environments and in both temperate and and in both temperate and tropical regions around the world tropical regions around the world Brown Algae: General

4 *Pelagic beds in Sargasso sea, Gulf of Mexico *Support host of creatures, from crustaceans, fish to young turtles Pelagic brown algae

5 Economic importance  Food, secondary products  Sources of alginates  Emulsifiers in everything from paint to ice cream  From kelp beds on US West Coast

6  Pigments  Chl a & c & fucoxanthin  Cell wall  Cellulose and mucilage  Plant body e.g., holdfast, stipe and blades  Reproduction/meiosis/life history  Most: sporic (haplodiplontic)  One order: gametic (diplontic) (diplontic) Brown Algae: General

7 Life history: alternation of generations Sporic meiosis: haplodiplontic: Laminariales

8 Life Histories Gametic meiosis: Diplontic: Fucales

9 Survey of Protistan assemblage *Dinoflagellates*Euglenophytes*Crytomonads The Heterokonts-Stramenopiles Oomycota Oomycota Diatoms Diatoms Brown algae Brown algae *Red algae *Green algae

10 Heterokonts-Stramenopiles  Large heterogeneous group characterized by two heterokont flagella  One smooth, one tinsel  Includes a variety of groups:  Oomycetes  Diatoms  Brown algae  Golden brown algae

11 Endosymbiosis events J. Phycol. Feb. 2009

12 * Kawai et al Protist Brown Algae Heterokonts

13 Current Taxonomic Treatment Classifications historically emphasizes four features: *Life history traits sporic to gameticsporic to gametic *Gamete types isogamous to oogamousisogamous to oogamous *Growth mode diffuse, meristems, trichothallic, apicaldiffuse, meristems, trichothallic, apical *Thallus morphology filamentous to parenchymatousfilamentous to parenchymatous

14 Gamete types

15 Diffuse Meristems Apical Growth mode

16 Evolutionary Relationships among Orders -Traditional hypotheses make a variety of assumptions regarding primitive and derived character states -Generally “simple to complex”: *Relationships among brown algal orders were proposed to reflect this progression *Basal groups have “simple” features *Derived lineages have more “complex” features

17 Traditional Hypothesis Wynne & Loiseaux 1976

18 From simple to more complex Is not a new concept Central theme in evolutionary thinking Common premise to our thinking of how many things have evolved from land plants to animal systems

19 Vascular tissue Gametophyte protection and retention Evolution of the seed Land Plant Evolution

20 Molecular Phylogeny -Molecular data have been used to test the “simple to complex” paradigm -Molecular data provides a very distinct picture of brown algal evolution: *“Simple” lineages are nested with more complex groups *Some early divergences involved “complex” lineages *Fucales nested within other lineages Basal in most traditional taxonomies

21 De Reviers et al. 2007

22 “Crown” group Basal Lineages Molecular Phylogeny De Reviers et al. 2007

23 What are the relationships among basal lineages and the “crown” group?What are the relationships among basal lineages and the “crown” group? Did brown algal evolution generally follow a “simple to complex” pattern?Did brown algal evolution generally follow a “simple to complex” pattern? –Pattern must be more complex than just “simple to complex” –General pattern still needs to be established Questions

24 Phylogeny from Phillips et al. (2008) J. Phycol. 44:394Phylogeny from Phillips et al. (2008) J. Phycol. 44:394 Lineages with ESTs (or genomic data) available (or expected) are in purpleLineages with ESTs (or genomic data) available (or expected) are in purple Libraries that we have produced and sequenced are:Libraries that we have produced and sequenced are: –Schizocladia, Choristocarpus, Desmarestia