Protist Diversity

Dinoflagellates

2000-­‐4000  speciesUnique  biflagellates

Flagella  beat  in  two  different  grooves

Causes  it  to  spin  like  a  top  when  moving

Stiff  cellulose  plates  form  theca

Gives  them  an  odd  armored  appearance

Dinoflagellates

About  half  are  heterotrophicIngest  solid  food  particles  or  dissolved  organic  carbon  

Even  some  of  the  photosynthetic  ones  may  feed  in  this  way-­‐-­‐-­‐mixotrophic

Often  are  symbionts called  zooxanthellae

Lose  theca  and  trade  autotrophic  production  for  protection  of  the  elementsCoral  reefs

Toxic  Blooms

During  unfavorable  conditions  Dinoflagellatesform  resting  cysts

Under  low  nutrient  levels  cysts  form,  and  drop  to  the  bottom,  may  be  transferred  by  ocean  currents,  finally  germinating  up  to  years  later

Acts  as  method  of  dispersalExplains  why  toxic  blooms  are  associated  with  sewage  and  agricultural  runoff

Pfiesteria actually  use  toxicity  -­‐and-­‐

Endosymbionts

Contain  a  diversity  of  photsynth pigments/  systems

Chl.  A  +  chl.  C  +  carotenoids(peridinin/fucoxanthin)    suggest  chrysophyteendosymbionts

Green  or  blue  green  plastids  which  suggest  ingestion  of  green  algae  and/or  cryptomonads

Reproduce  via  longitudinal  cell  division  but  sexual  repro  shows  up  in  multiple  lineages

Dinoflagellate Bioluminescence  

http://www.youtube.com/watch?v=EN1Yxq8KMsw

Euglenoids

~  900  species,  earliest  were  most  likely  particle  eaters

Autotrophic  Euglenoids contain  chl.  a  and  chl.  b  

Euglenoids most  likely  get  photosynth capabilities  from  green  algae  (Chlorophyta)

Euglenoids

Lack  a  cell  wall  but  contain  a  pellicle

Allows  from  some  rigidity  and  flexibility  in  size  of  the  cell

Also  contain  a  photosensingeyespot   stigma

Located  near  the  base  of  the  flagellum  (the  anterior! end)

http://www.youtube.com/watch?v=hiZ85y0g3UI

Reproduce  via  lengthwise  cytokinesis

No  knowledge  of  sexual  Euglenoids

Cryptomonads

Small  protists occurring  often  in  cold  or  subsurface  waters

Dominant  plankton  in  either  high  latitude  or  seasonal  cold  water

Once  again  have  colorless  phagocytic membersContain  phycobilins in  addition  to  chl.  a  and  cStrong  evidence  for  secondary  endosymbiosis of  red  algae  (who  get  their  chloroplasts  from  cyanobacteria)Repro  is  generally  asexual  with  recent  reports  of  sex  in  some  lineages

Cryptomonads

Haptophytes

Primarily  marine  ~  300  species  in  ~  80  genera

Most  distinctive  structure  is  haptonemaThreadlike  structure  extending  from  the  cell  along  with  two  flagella

Flagella  are  of  equal  size  and  haptonema is  reduced

Haptophytes

Coccoliths are  another  distinguishing  character  of  haptophytes

Calcified  scales  

Photosynthetic  haptophytes contain  chl.  a  and  c  Some  contain  fucoxanthin

Similar  to  brown  algae,  crysophytes,  and  diatoms

Chloroplasts  also  contain  chl endoplasmic  reticulum

Another  sign  of  secondary  endosymbiosis

Coccolith

Haptophytes

Important  producers  of  sulfur  oxides

Also  contribute  2/3  of  all  calcium  carbonate  transfer  to  deep  ocean  (carbon  sink)

Coccoliths

May  also  produce  ocean  blooms  covering  thousands  of  square  kilometers  

Heterokonts

Also  referred  to  as  stramenopiles

Flagella  usually  occur  in  pairs  one  ornamented  and  longer  (tinsel)  and  the  other  shorter  and  smoother  (whiplash)

Grouping  of  the  four  phylum  (oomycetes,  chrysophytes,  diatoms,  and  brown  algae)  consistent  with  molecular  phylogenies

Heterokont appears  to  be  a  monophyletic  character

Heterokonts

Oomycota (water  molds)Heterotrophic  group

Important  plant  pathogensSexual  reproduction  is  Oogamus

Female  gamete  is  large  and  nonflagellatedFamiliar?

Characteristic  of  some  brown,  red  and  green  algae  as  well  as  bryophytes  to  vascular  plantsOne  of  the  first  synapomorphic characters  giving  us  insight  into  derived  plant  lineagesAlso  prevalent  in  animal  lineages  (parallel  evolution)

Oomycota

Phytophthoradestruction  of  many  crops  

cacao,  pineapples,  tomatoes,  rubber,  papayas,  onions,  strawberries,  apples,  soybeans,  tobacco,  and  citrus

Can  also  be  a  serious  problem  in  turfgrass,  golf  courses,  and  athletic  fields

Cause  of  >800,000  deaths  during  the  potato  famine

Diatoms

Diverse  protist phyla  of  100,000  +  species

Well  preserved  fossil  record

Can  be  tremendous  in  number30-­‐50  million  individuals  of  on  1  square  cm(!!)  of  rock

Walls  consist  of  two  frustules  Overlapping  silica  halves

Diatoms

Mostly  asexualSome  sexual  forms  showing  gametic meiosis

Centric  forms  are  oogamousPennate forms  are  isogamous

Sexual  reproduction  leads  to  empty  frustuledeposition  of  SiMay  also  form  resting  stages  which  sink  down  to  the  bottom  and  germinate  in  more  favorable  conditions

Frustule halves  become  progressively  smaller