Euglenophyta, Cryptophyta and Haptophyta

Outline

Euglenophyta

Introduction

a.k.a. euglenoids

mostly unicellular, freshwater

Cells

Flagella --

  • two of 'em -- short and long
  • originate in reservoir
  • eyespot -- associated with flagellar swelling
  • contractile vacuole

Pellicle

  • proteinaceous, flexible
  • euglenoid motion

Chloroplasts -- typically:

  • chlorophylls a and b + carotenoids
  • 3 membranes
  • thylakoids in stacks of three
  • paramylon = reserve polysaccharide

former green?

Nucleus -- weird

"mesokaryotic" nucleus

chromosomes always condensed

mitosis

  • nuclear envelope persists (closed mitosis)
  • spindle apparatus microtubules form inside nucleus -- organized by basal bodies of flagella
  • cell division is longitudinal

Life cycle -- no sexual reproduction

Ecology

habitat & nutrition

  • freshwater, but with high organic content
  • 1/3 autotrophic -- actually auxotrophic
  • 2/3 heterotrophic

Cryptophyta

Intro

primarily unicellular flagellates

freshwater or marine

mixotrophic

Cells

flagella --2, both tinsel

gullet -- allows ingestion

periplast

  • proteinaceous outer covering
  • has trichocysts

chloroplast

  • chls a and c
  • phycoerythrin and phycocyanin but no phycobilisomes
  • 4 chloroplast membranes

    nucleomorph -- reduced eukaryotic nucleus

    former red?

Ecology

lake phytoplankton

Mesodinium

a ciliate with a reduced cryptophyte endosymbiont

Haptophyta

Intro

about 500 spp.

mostly unicellular flagellates (also multicellular, filamentous and nonflagellated)

Cells

flagella

2 smooth

haptonema

flexible, with microtubules, for capture of prey

scales

organic and/or calcified (covered in CaCO3)

Coccolithophorids -- nonflagellated, with calcified scales

chloroplast

  • chls a and c
  • fucoxanthin
  • thylakoids in 3's
  • 4 membranes
  • store chrysolaminarin in vesicle

    -- related to heterokont chloroplast (?)

Life cycle

varied, often change morphology in different stages

Ecology and importance

primary producers

coccolithophorids et al. important in ocean

calcium carbonate (CaCO3) deposition

chalk deposits, takes CO2 from atmosphere

dimethyl sulfide (DMS) production

cloud formation

toxic/noxious effects

Vocabulary

click here to go to miscellaneous algae vocabulary

 

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