sign in sign up
<<
Home , Phaeothamniophyceae, Red algae

University of California, Santa Cruz

ALGAE OF , Cladophorales Name Acrosiphonia coalita (Ruprect) R.F. Scagel, D.J . Garbary, L.Golden & M.J.Hawkes Location Davenport Landing , Santa Cruz, California

Habitat found in low intertidal, growing on rocks

Collected by your name Date April 19, 2014 No. 1

Identified by your name Date April 19, 2014

Heterokontophyta Phaeostrophion irregulare Setchell & N.L. Gardner

• Midterm in one week (Monday, April 28)

• Format: • Definitions • Short Answer • Ps/I Curve • Dichotomous key • History • A couple of matching sections • Short Essays

1 Dichotomous Key: Cannot use names of groups, instead characteristics

Example: Chlamydomonas, Dictyota, Halimeda

Has Chlorophyll C No Chloropyll c Dictyota

Forms palmelloid stage No palmelloid stage Chlamydomonas Halimeda

Division: Heterokontophyta Or (, Chromophyta, Phaeophyta)

~ 13,151 species 99% marine

2 Brief history of photosynthetic organisms on earth

3.45 bya = appear and introduce

1.5 bya = first appeared (nuclear envelope and ER thought to come from invagination of plasma membrane)

0.9 bya = first multicellular (Rhodophyta - )

800 mya = earliest Chlorophyta ()

400-500 mya = on land – derived from

250 mya = earliest Heterokontophyta ()

100 mya = earliest seagrasses (angiosperms)

DOMAIN Groups () 1.- cyanobacteria (blue green algae) 2.Archae “Algae” 3.Eukaryotes 1. -

2. - , heterokonyophyta

3. - unicellular amoeboids

4. Excavates- unicellular

5. Plantae- rhodophyta, chlorophyta, seagrasses

6. Amoebozoans- slimemolds

7. Fungi- with extracellular digestion

8. - unicellular

9. - multicellular heterotrophs 6

3 Heterokontophyta Characteristics: 1) Pigments?

2) structure?

3) Storage product?

4) Flagella? 2

Division: Heterokontophyta

Many classes, mostly unicellular or colony of unicells: • : Chrysophyceae • class: Synurophyceae • class: • class: • class: Raphidophyceae • class: Xanthophyceae • class: Eustigmatophyceae • class: Tribophyceae • class: Phaeothamniophyceae • class: Phaeophyceae*** *** We will focus on marine macroalgae

1

4 Algal

Hierarchical system of classification:

Level: suffix: example: Group Stramenopiles Division -phyta Heterokontophyta Class -phyceae Phaeophyceae -ales Laminariales Family -aceae Lessoniaceae Genus Egregia species menziesii

Phaeophyceae Metabolites:

Tannins (a.k.a. polyphenolic compounds) and terpenes - Anti-endophyte, -epiphyte, and anti-herbivory -Stored in special vesicles called physodes in the cytoplasm -May strength walls by interacting with alginates -Block UVB protecting algae from radiation damage

4

5 Phaeophyceae Storage Products:

•laminaran and mannitol are most abundant •Always sugars, never starch •Storage products found in

4

Seawater is hypotonic (less saline) than most algal cells

Phaeophyceae Storage Products :

Mannitol function •important in osmoregulation- algae make more mannitol to use up ions-> algal salinity decreases

•transporting organic material to different parts of the in large species

•lowers freezing point

6 Phaeophyceae Flagella: flagella:

Anterior “flimmer ” •used for movement • long flagellum with two rows of stiff hairs (“mastigoneme”) • directed forward

Posterior “whiplash flagellum” •used for steering • short, smooth flagellum • directed backward • contains flavin which functions as a photoreceptor

• an eyespot acts a shading structure or light reflector

Flagella attached laterally not apically 5

Phaeophyceae Thallus Morphology:

- Advanced forms: complex multicellular thalli - Not unicellular (except and ) - Simplest forms are branching filaments - More complex forms are parenchymatous and pseudoparenchymatous - Differentiation of cortex (outer pigmented cells) and medulla (inner non-pigmented cells) - Medullary cells  primarily for storage or transport - Some browns quite large  over 40 meters long

6

7 Phaeophyceae Morphology of Cell Walls

Two main components:

1. Cellulose  microfibrils (1-10% of thallus dry weight) Function: structural support

2. Alginic acid  surrounds the microfibrills (35% of thallus dry weight) Function: elasticity; flexibility; prevent desiccation; and osmoregulation (ion exchange)

7

Phaeophyceae Alginates: Alginates = salt form of alginic acid; primarily in intercellular matrix

•Alginates = Alginic acid + an Ion

• Details of how alginates are used in helping ion exchange are not well understood.

• One proposed mechanism is that preferentially using some ions and not others helps to balance overall ion levels.

• Common ions that are used to make alginates are Ca, Na and Mg 8

8 Phaeophyceae Alginates:

Human uses for alginates 

- Ice-cream  prevents ice crystal formation

- Frosting  water retaining properties; prevent drying

- Paints  emulsifying agent; keeps pigments suspended and prevents brush streaking

- Pharmaceuticals

- Food  “kombu” in Japan; dried and shredded laminarians

8

Algal life histories : Terminology

Sporophyte: diploid, 2n, multicellular release spores

Sporangia = structure where spores are formed

Spore (mitospore, meiospore): unicellular, must settle & grow, product of (Mt) or meiosis (Me)

Gametophyte: hapliod, 1n, multicellular release gametes

Gametangia = structure where gametes are formed

Gamete: unicellular, must fuse or die, product of mitosis(Mt) or meiosis (Me)

9 Phaeophyceae Reproduction: Gametangia = structure where gametes are formed

Sporangia = structure where spores are formed

uniseriate multiseriate

Unilocular = all spores/gametes Plurilocular = divided into are produced in a single compartment many small chambers (locules); one / “unangia” per chamber

“plurangia” 10

Phaeophyceae Reproduction: Functional How do the male gametes find the female ones?

Pheromones = chemicals produced to elicit a specific behavioral or physiological response from another individual.

Many Phaeophyceans produce sexual pheromones, all are chemically similar (unsaturated hydrocarbons). Similarity  high cross-reactivity

Male gametes are VERY sensitive to pheromones: very low concentration will elicit a response 11

10 Phaeophyceae Reproduction: Functional Anisogamy female gamete male gamete

12

Phaeophyceae habitat:

• 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

13

11 Division: Heterokontophyta- 13,151 species

Class: Phaeophyceae – 1,836 species Order: 19 orders but we will focus on 6 1. -529 species 2. -696 species 3. Desmerestailes- 26 species 4. - 242 species 5. - 54 species 6. Laminariales- 129 species

14

Distinguishing among orders based on

1. Life History and Reproduction • Isomorphic/heteromorphic alt. of gen.; diplontic • Isogamous, anisogamous, oogamous

2. Macrothallus Construction: • Filamentous • Parenchymatous • Pseudoparenchymatous

3. Growth • Diffuse • Apical • Intercalary • Trichothallic • Meristodermal-a surface layer of cells (epidermis) that is capable of dividing (is meristematic)

15

12 Division: Heterokontophyta- 13,151 species

Class: Phaeophyceae – 1,836 species Order: 19 orders but we will focus on 6 1. Fucales -529 species - Usually saxicolous - Unattached in some cases - Unilocular gametangia

Genus: Fucus Silvetia Pelvetiopsis Sargassum Cystoseira

14

Order: Fucales

1. Life History and Reproduction

2. Macrothallus Construction:

3. Growth

26

13 Life History of Fucales Diplontic: 2N thallus, the gametes are the only haploid stage

27

Receptacle - swollen tips of fucoids where meiosis occurs - terminal portion of a branch bearing numerous embedded

Conceptacles - chambers where the gametes are stored

28

14 Conceptacles

Oogonia- female reproductive cell containing one or more egg (gamete)

Antheridia- a male reproductive structure producing motile male gametes

29

Monoecious- having the male & female reproductive structure borne on the same individual plants -one house

Dioecious- having the male & female reproductive structure borne on separate individual plants; said of the species -two houses

30

15 Fucus Silvetia Pelvetiopsis

Midrib Playdough stipe Flattened stipe

1 egg per 8 eggs per oogonium 2 eggs per oogonium oogonium31

Sargassum: Sargasso Sea in the Atlantic

=Unattached Sargassum spp  rafts

32

16 Cystoseira Sargassum

33

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

-catenate series -singly 34

17 Division: Heterokontophyta- 13,151 species

Class: Phaeophyceae – 1,836 species Order: 19 orders but we will focus on 6 2. Ectocarpales-696 species - Saxicolous or epiphytic - Uniseriate filaments - Opportunistic spp, excellent colonizers -Female gametes releases pheromone ectocarpene

Genus: Ectocarpus Haplogloia

14

Order: Ectocarpales:

1. Life History and Reproduction:

2. Macrothallus Construction:

3. Growth:

17

18 Life History of Ectocarpales:

17

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

14

19 Order:

1. Life History and Reproduction:

2. Macrothallus Construction:

3. Growth

30

Life History of Desmarestiales

31

20 - 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 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

21