University of California, Santa Cruz • Midterm in one week (Monday, April 28) ALGAE OF Chlorophyta, Cladophorales Name Acrosiphonia coalita (Ruprect) R.F. Scagel, D.J . • Format: Garbary, L.Golden & M.J.Hawkes • Definitions Location Davenport Landing , Santa Cruz, California • Short Answer • Ps/I Curve Habitat found in low intertidal, growing on rocks • Dichotomous key • Life History Collected by your name Date April 19, 2014 No. 1 • A couple of matching sections • Short Essays Identified by your name Date April 19, 2014 Heterokontophyta Incertae sedis Phaeostrophion irregulare Setchell & N.L. Gardner Dichotomous Key: Cannot use names of Division: Heterokontophyta groups, instead characteristics Or (Ochrophyta, Chromophyta, Phaeophyta) Example: Chlamydomonas, Dictyota, Halimeda Has Chlorophyll C No Chloropyll c Dictyota Forms palmelloid stage No palmelloid stage Chlamydomonas Halimeda ~ 13,151 species 99% marine 1 Groups (Kingdom) Brief history of photosynthetic organisms on earth DOMAIN 1.Bacteria- cyanobacteria (blue green algae) 3.45 bya = Cyanobacteria appear and introduce 2.Archae photosynthesis “Algae” 3.Eukaryotes 1. Alveolates- dinoflagellates 1.5 bya = first Eukaryotes appeared (nuclear envelope and ER thought to come from invagination of plasma membrane) 2. Stramenopiles- diatoms, heterokonyophyta 0.9 bya = first multicellular algae (Rhodophyta - Red algae) 3. Rhizaria- unicellular amoeboids 800 mya = earliest Chlorophyta (Green algae) 4. Excavates- unicellular flagellates 400-500 mya = plants on land – derived from Charophyceae 5. Plantae- rhodophyta, chlorophyta, seagrasses 250 mya = earliest Heterokontophyta (Brown algae) 6. Amoebozoans- slimemolds 100 mya = earliest seagrasses (angiosperms) 7. Fungi- heterotrophs with extracellular digestion 8. Choanoflagellates- unicellular 9. Animals- multicellular heterotrophs 6 Heterokontophyta Characteristics: Division: Heterokontophyta 1) Pigments? Many classes, mostly unicellular or colony of unicells: • class: Chrysophyceae • class: Synurophyceae 2) Chloroplast structure? • class: Dictyochophyceae • class: Pelagophyceae • class: Raphidophyceae • class: Xanthophyceae • class: Eustigmatophyceae 3) Storage product? • class: Tribophyceae • class: Phaeothamniophyceae • class: Phaeophyceae*** *** We will focus on marine macroalgae 4) Flagella? 2 1 2 Algal taxonomy Phaeophyceae Metabolites: Hierarchical system of classification: Tannins (a.k.a. polyphenolic compounds) and terpenes Level: suffix: example: - Anti-endophyte, -epiphyte, and anti-herbivory Domain Eukaryote Group Stramenopiles -Stored in special vesicles called physodes in the Division -phyta Heterokontophyta cytoplasm Class -phyceae Phaeophyceae -May strength cell walls by interacting with alginates Order -ales Laminariales Family -aceae Lessoniaceae -Block UVB protecting algae from radiation damage Genus Egregia species menziesii 4 Phaeophyceae Storage Products: Seawater is hypotonic (less saline) than most algal cells •laminaran and mannitol are most abundant Phaeophyceae Storage Products : •Always sugars, never starch •Storage products found in pyrenoids Mannitol function •important in osmoregulation- algae make more mannitol to use up ions-> algal salinity decreases •transporting organic material to different parts of the thallus in large species •lowers freezing point 4 3 Phaeophyceae Flagella: Phaeophyceae Thallus Morphology: Heterokont flagella: - Advanced forms: complex multicellular thalli Anterior “flimmer flagellum” •used for movement - Not unicellular (except gametes and spores) • long flagellum with two rows of - Simplest forms are branching filaments stiff hairs (“mastigoneme”) • directed forward - More complex forms are parenchymatous and pseudoparenchymatous - Differentiation of cortex (outer pigmented cells) and medulla (inner non-pigmented cells) Posterior “whiplash flagellum” •used for steering - Medullary cells primarily for storage or transport • short, smooth flagellum - Some browns quite large over 40 meters long • directed backward • contains flavin which functions as a photoreceptor • an eyespot acts a shading structure or light reflector Flagella attached laterally not apically 5 6 Phaeophyceae Morphology of Cell Walls Phaeophyceae Alginates: Alginates = salt form of alginic acid; primarily in Two main components: intercellular matrix 1. Cellulose microfibrils (1-10% of thallus dry weight) •Alginates = Alginic acid + an Ion Function: structural support • Details of how alginates are used in helping ion 2. Alginic acid surrounds the microfibrills (35% of thallus dry exchange are not well understood. weight) Function: elasticity; flexibility; prevent desiccation; and • One proposed mechanism is that preferentially using osmoregulation (ion exchange) some ions and not others helps to balance overall ion levels. • Common ions that are used to make alginates are Ca, Na and Mg 7 8 4 Algal life histories : Terminology Phaeophyceae Alginates: Sporophyte: diploid, 2n, multicellular release spores Human uses for alginates - Ice-cream prevents ice crystal formation Sporangia = structure where spores are formed - Frosting water retaining properties; prevent drying Spore (mitospore, meiospore): unicellular, must settle & grow, product of mitosis(Mt) or meiosis (Me) - Paints emulsifying agent; keeps pigments suspended and prevents brush streaking - Pharmaceuticals Gametophyte: hapliod, 1n, multicellular release gametes - Food “kombu” in Japan; dried and shredded laminarians Gametangia = structure where gametes are formed Gamete: unicellular, must fuse or die, product of mitosis(Mt) or meiosis (Me) 8 Phaeophyceae Reproduction: Phaeophyceae Reproduction: Gametangia = structure where gametes are formed Functional Anisogamy Sporangia = structure where spores are formed How do the male gametes find the female ones? uniseriate multiseriate Pheromones = chemicals produced to elicit a specific behavioral or Plurilocular = divided into physiological response from another individual. Unilocular = all spores/gametes many small chambers are produced in a single compartment Many Phaeophyceans produce sexual pheromones, all are chemically similar (locules); one spore/gamete per chamber (unsaturated hydrocarbons). Similarity high cross-reactivity “unangia” “plurangia” Male gametes are VERY sensitive to pheromones: very low concentration will elicit a response 10 11 5 Phaeophyceae Reproduction: Phaeophyceae habitat: Functional Anisogamy female gamete male gamete • Mostly marine (or at least brackish water) • Intertidal and subtidal • Dominate colder waters Northern hemisphere: # of red species > # of brown species # of red individuals << # of brown individuals Browns are less diverse but more abundant 12 13 Division: Heterokontophyta- 13,151 species Distinguishing among orders based on 1. Life History and Reproduction Class: Phaeophyceae – 1,836 species • Isomorphic/heteromorphic alt. of gen.; diplontic • Isogamous, anisogamous, oogamous Order: 19 orders but we will focus on 6 1. Fucales -529 species 2. Macrothallus Construction: • Filamentous 2. Ectocarpales-696 species • Parenchymatous 3. Desmerestailes- 26 species • Pseudoparenchymatous 4. Dictyotales- 242 species 3. Growth 5. Ralfsiales- 54 species • Diffuse 6. Laminariales- 129 species • Apical • Intercalary • Trichothallic • Meristodermal-a surface layer of cells (epidermis) that is capable of dividing (is meristematic) 14 15 6 Division: Heterokontophyta- 13,151 species Order: Fucales Class: Phaeophyceae – 1,836 species Order: 19 orders but we will focus on 6 1. Life History and Reproduction 1. Fucales -529 species - Usually saxicolous - Unattached in some cases 2. Macrothallus Construction: - Unilocular gametangia Genus: Fucus Silvetia 3. Growth Pelvetiopsis Sargassum Cystoseira 26 14 Life History of Fucales Diplontic: 2N thallus, the gametes are the only Receptacle haploid stage - swollen tips of fucoids where meiosis occurs - terminal portion of a branch bearing numerous embedded conceptacles Conceptacles - chambers where the gametes are stored 27 28 7 Conceptacles Monoecious- having the male & female reproductive structure borne on the same individual plants -one house Oogonia- female reproductive cell containing one or more egg (gamete) Dioecious- having the male & female reproductive structure borne on separate individual plants; said of the species -two houses Antheridia- a male reproductive structure producing motile male gametes 29 30 Sargassum: Fucus Silvetia Pelvetiopsis Sargasso Sea in the Atlantic =Unattached Sargassum spp rafts Midrib Playdough stipe Flattened stipe 1 egg per 8 eggs per oogonium 2 eggs per oogonium oogonium31 32 8 Cystoseira Sargassum Pneumatocysts- -a large float containing gas found in heterokontophyta -provide buoyancy to lift the blades toward the surface, allowing them to receive more sunlight for Ps - can hold O2, CO2, CO Cystoseria osmundacea Sargassum muticum 33 -catenate series -singly 34 Division: Heterokontophyta- 13,151 species Order: Ectocarpales: Class: Phaeophyceae – 1,836 species Order: 19 orders but we will focus on 6 1. Life History and Reproduction: 2. Ectocarpales-696 species - Saxicolous or epiphytic - Uniseriate filaments - Opportunistic spp, excellent colonizers 2. Macrothallus Construction: -Female gametes releases pheromone ectocarpene Genus: Ectocarpus 3. Growth: Haplogloia 14 17 9 Life History of Ectocarpales: Division: Heterokontophyta- 13,151 species Class: Phaeophyceae – 1,836 species Order: 19 orders but we will focus on 6 3. Desmerestailes- 26 species - Saxicolous - Low intertidal to subtidal - “Acid weed” Genus Desmarestia 17 14 Life History of Desmarestiales Order: Desmarestiales 1. Life History and Reproduction: 2. Macrothallus Construction: 3. Growth 30 31 10 - Morphology variable within the genus -Subtidal, but grows well in high light (very abundant if disturbance has removed other plants or canopy, e.g. El Nino, or urchin grazing) - Disappears with kelp growth due to canopy cover; shading - ”Acid weed”: cells accumulate sulfate ions from seawater which reacts with water to produce sulfuric acid or malic acid, stored in vacuoles =ANTIHERBIVORY, pH 0.8-1.8, bleaches other algae 32 11 .