Phylum Apicomplexa

Gregarines, Coccidians

~ 5,000 species

All parasitic
Apical complex

Organelles for attaching parasite to host
cell

Hooks/suckers
Plasmodium vivax

Causes malaria

Kills 1-3 million / year

Mostly in Africa

Vector = mosquito
http://www.cdc.gov/malaria/about/biology/
Malaria: important world-wide
disease
•
•
•
> 300-500 million infections / year
> 1 million deaths / year
Distinctive fever pattern – cyclic 48 hours
Gregarine: gut parasites of
many invertebrates


Best known from arthropods
sporozoite
spores
In beetle
Phylum Dinoflagellata

~ 4,000 species described

Most unicellular, some are filamentous
or colonial

Some planktonic, some symbiotic (w/
corals, other cnidarians)
Red tide caused by
dinoflagellates

Discolored area of ocean with billions of
dinoflagellates

Produce toxins, kill everything.
Two flagella: armor or not
Ceratium
Ceratium sp.
Noctiluca
Dinoflagellates


Freshwater and marine
Osmoregulation by pusules


Tubules that open to outside
Autotrophic and heterotrophic


Switch
Many photo pigments
Repro

Asexual
Sexual: haploid cells divide, produce
daughter cells = gametes

Forms cyst, resting stage

Phylum Rhizopoda: amebas

~ 200 species

Most free-living, some endosymbiotic,
some pathogenic

Pseudopodia in all
Entamoeba histolytica
Amebic dysentery

4 nuclei - cyst found in fecal smear
Difflugia
Phylum Actinopoda

~4,240 species

Radiolarians, Heliozoans, etc.
Most w/internal siliceous skeletons
Planktonic and benthic
Heterotrophic mostly (phagocytosis)
Binary fission, budding, sex rare




Actinopoda

“ray feet” = axopodia


Slender pseudopodia
Actinosphaerium
Actinosphaerium
Foraminifera




~ 40,000 species
All aquatic habitats
Some planktonic, most benthic
Tests form chalks, marble, limestone
Chalk cliffs of Dover
Phylum Diplomonadida

Plasma membrane rigid from three
microtubular roots

Most phagotrophic, feed on bacteria

Asexual, most form cysts
Giardia




No mitochondria, ER, or Golgi bodies
Warm climates mostly
In severe infections every cell in gut is
covered by a parasite.
Coating of inside of intestine interferes
with absorption
Giardia lamblia
Phylum Chlorophyta




“Green algae” - green chloroplasts
Like plants
Some colonial
Some have lost photosynthesis =
heterotrophs
Volvox
Phylum Opalinida




Many rows of cilia - different than in
ciliates
Reproduction is longitudinal (like
flagellates), not transverse (ciliates)
~ 150 species
Endosymbiotic in frog and toad gut
Phylum Opalinida



Sexual repro by synamy
Asexual = binary fission
Opalina
Protist Phylogeny

Origins ~ 2.5 bya

Evolution of eukaryotes?

Serial Endosymbiotic Theory (SET)
Serial endosymbiotic theory