Protists

ProtistsThere are NO

typical protists.

Protist General Characteristics

- usually single cell

- eukaryotic

- paraphyletic group

Protists

Traditional Classification

There are three divisions of the

Kingdom Protista: Protozoa,

Algae, and Fungi-like

ProtistsNew Classification Method

Four Major Groups

Excavata

SAR Clade

Archaeplastida

Unikonata

Protists

ExcavatesExcavates

- contain modified mitochondria

- contain “excavated” feeding groove

Parabasalids

- found with animals

- flagellated

- hydrogenosomes

Ex: Trichomonas vaginalis &

Trichonympha

Protists

ExcavatesDiplomonads

- found with animals or in stagnant water

- flagellated

- mitosomes – modified mitochondria

- Ex: Giardia lamblia

Protists

Excavates - EuglenozoansEuglenozoans

2 groups – Euglenids & Kinetoplastids

- photoautotrophs,

parasites &

heterotrophs

Euglenids

- pellicle

- 1 or 2 flagella

- can be autotrophic or heterotrophic (mixotrophs)

- Ex: Euglenoids

Protists

Excavates - Euglenozoans

Kinetoplastids

- contain a kinetoplast

- some cause disease

- Ex: trypanosomes

Protists

SAR CladeAlveolates

-have alveoli, membrane

bound flattened sacs

beneath the cell

membrane

-have mitochondria with

tubular cristae

Dinoflagellates

Apicomplexans

Ciliates

Stramenopiles

- contain 2 flagella at

some point in their life;

one is covered with

tubular hairs

Diatoms

Golden Algae

Brown Algae

(Oomycetes)

Rhizarians

The Amoeba Group

Forams

Cercozoans

Radiolarins

Protists

SAR Clade - Alveolates

Dinoflagellates

- contain 2 flagella

- cell walls composed of cellulose plates

- fresh and saltwater varieties

- half of the species are photosynthetic

- unicellular

- responsible for bioluminescence and red

tides (Gymnodinium & Gonyaulax)

Gonyaulax

Protists

SAR Clade - Alveolates

Protists

SAR Clade - Alveolates

Apicomplexa

- contain a group of organelles called the apical

complex

- complex life cycles (sexual & asexual stages)

- Sporozoites spread through the host

- Ex: Plasmodium, Toxoplasma & Cryptosporidium parvum

Protists

SAR Clade - Alveolates

Apicomplexa

Ciliates

Ciliates

- use cilia for movement

- oral groove, feed on bacteria, algae and other

small organisms

- some have trichocysts

- contractile vacuoles – regulate water

- multinucleate

- macronucleus- multiple copies of DNA,

responsible for metabolic and development

functions (diploid)

- micronucleus- smaller, participates in

conjugation (haploid)

Example: Paramecium & Euplotes

Protists

SAR Clade - Alveolates

Ciliates

Protists

SAR Clade - Alveolates

Water Molds

Oomycetes

- fuzzy, white growths (resemble fungi)

- diploid

- cell walls made of cellulose

- absorb nutrients from the environment

- Ex: water molds, white rusts, downy

mildews

Protists

SAR Clade - Stramenopiles

Diatoms

Diatoms

- Silica shells (frustules) that nest together

- Photosynthetic (phytoplankton)

- Diatomaceous earth

Protists

SAR Clade - Stramenopiles

Diatoms

Protists

SAR Clade - Stramenopiles

Brown Algae

Brown Algae

- multicellular

- contain fucoxanthin (pigment)

- contain algin in cell walls

- live in cold saltwater along rocky

coasts

- have hold-fast, stipe and blade

- many have air bladders so they can

float near the surface

Examples: kelp, seaweeds

Protists

SAR Clade - Stramenopiles

Brown Algae Protists

SAR Clade - Stramenopiles

Fucus

Protists

SAR Clade - Stramenopiles

Brown Algae

Golden Algae

Golden Algae

-Yellow & brown carotenoids

-2 flagella

-Photosynthetic

-Mixotrophic

-Able to form cysts

-Unicellular & some colonial

Protists

SAR Clade - Stramenopiles

Golden Algae

Protists

SAR Clade - Stramenopiles

Radiolarians

- symmetrical internal silica skeletons

- pseudopods radiate from the central body

Forams (Foraminiferans)

- porous shells called tests

- tests have calcium carbonate

- pseudopods for swimming, test formation

& feeding

Cercozoans

- heterotrophs; some parasitic

- amoeboid movement

- few mixotrophic

Protists – SAR Clade

Rhizarians

Radiolarians

Forams (Foraminiferans)

Cercozoans

Protists – SAR Clade

Rhizarians

Archaeplastida

- monophyletic group

- a heterotrophic protist engulfed a

cyanobacterial endosymbiont giving

rise to red and green algae

Protists - Archaeplastida

Red Algae

Red Algae

- multicellular

- modified form of starch

- lack roots, stems and leaves

- use holdfasts to attach to rocks

- most live in deep saltwater, some on land and

fresh water

- some contain phycoerythrin- pigments to absorb

wavelengths of light that penetrate deep into

the ocean

- some contain chlorophyll a

- used for cosmetics, cheeses and agar

production

Protists –

Archaeplastida – Red Algae

Red Algae

Protists –

Archaeplastida – Red Algae

Green Algae

Green Algae

- most diverse algae group

- 2 main groups: charophytes & chlorophytes

- diverse range of habitats from oceans

to the fur of sloths

- unicellular, multicellular, filamentous,

tubular, blade-like and colonial

varieties

- asexual and sexual reproduction

- use chlorophyll a

and chlorophyll b

- cellulose cell walls

- - no roots, stems or leaves

- contain pyrenoids

- use starch as a storage carbohydrate

Protists –

Archaeplastida – Green Algae

Green Algae

Protists –

Archaeplastida – Green Algae

Protists –

Unikonata - Amoebozoans

• Very diverse group

• Amoebozoans & Opisthokonts

- no cell wall

- form pseudopodia- a cytoplasm

containing extension of the plasma

membrane

- asexual reproduction

Examples:

Turbulinids,

Entamoebas and Slime Molds

Protists –

Unikonata - Amoebozoans

Amoebas

Protists –

Unikonata - Amoebozoans

Protists –

Unikonata –

Amoebozoans

Slime Molds

Slime Molds (Mycetozoans)

- live in cool, moist, shady places

- wide color ranges

- fungus like because they produce spores

- animal like because they move around and engulf

food

- 2 types of slime molds: plasmodial slime molds

and cellular slime molds

Protists –

Unikonata - Amoebozoans

Slime Molds

- Acellular (Plasmodial) Slime Molds

*form a plasmodium- A mass of cytoplasm that

contains nuclei but no cell membranes or cell

walls to divide the mass into individual cells

*release haploid spores when dry or there is a

lack of food (unfavorable conditions)

- Cellular Slime Molds

*spend part of their life as an independent cell

and when food is scarce the independent cells

join together

*have a pseudoplasmodium

Protists –

Unikonata - Amoebozoans

Cellular Slime Molds

Plasmodial Slime

Molds

Protists –

Unikonata - Amoebozoans

Tubulinids

Tubulinids

- have tube-shaped or lobe-shaped pseudopods

- heterotrophic

- soil dwelling and both fresh and saltwater

varieties

Protists –

Unikonata - Amoebazoans

Amoeba proteus

Entamoebas

Entamoebas

- parasitic- infect all vertebrates and some invertebrates

- E. histolytica causes dysentery

Protists –

Unikonata - Amoebazoans

Entamoeba histolytica

Opisthokonts

Diverse group including protists, animals and

fungi.

Nucleariids – closely related to fungi

Choanoflagellaes – closely related to animals

Protists –

Unikonata - Opisthokonts