Eukaryotes

• Protista, Fungi, Plantae, Animalia• Complex• >10x larger• DNA in nucleus• Cell membrane

– Some also have cell wall• Membrane bound organelles

– specialization

Protista• Very diverse• mostly unicellular, some colonial, some

multicellular (w/simple tissues)• Autotrophs

– Plant-like

• Heterotrophs– Animal-like protozoans– Fungal-like

• Mixotrophs– Photoautotrophic and heterotrophic pathways

• Aquatic or moist environments

• Eukaryotes that share some Archaea characteristics (e.g. biochemistry & genetics)– Lacks the peptidoglycons in cell walls of bacteria

• Otherwise varies in modes of Eukarya reproduction, locomotion, & morphology

• Endocytosis; 1o endosymbiosis with prokaryotes (Fig 28.3)– 2o endosymbiosis: heterotroph engulfing red or green algae

Protistan origin

Figure 28.2

Diplomonads

Parabasalids

Euglenozoans

Dinoflagellates

Apicomplexans

Ciliates

Diatoms

Golden algae

Brown algae

Oomycetes

Cercozoans

Forams

Radiolarians

Red algae

Chlorophytes

Charophytes

Land plants

Slime molds

Gymnamoebas

Entamoebas

Nucleariids

Fungi

Choanoflagellates

Animals

Alveolates

Stramenopiles

Green

algae

Am

oebozoansO

pisthokonts

ExcavataC

hromalveolata

Rhizaria

Archaeplastida

Unikonta

SAR clade (10th ed)

“…protist phylogeny continues to emerge…changing rapidly…”(Campbell 28.1)

• Five Supergroups:– Excavata– Chromalveolata– Rhizaria– Archaeplastida– Unikonta

“…it may be helpful to focus less on the specific names of groups of organisms and more on why the organisms are important…” (Campbell 28.1)

Functionally…“Animal-like” Protozoans

heterotrophic consumers“Fungi-like” Protists

share fungal characteristics; many moved back/forth from Fungi

“Plant-like” Algaenon-plant, photosynthetic aquatic eukaryotes

Figure 28.2Diplomonads

Parabasalids

Euglenozoans

Dinoflagellates

Apicomplexans

Ciliates

Diatoms

Golden algae

Brown algae

Oomycetes

Cercozoans

Forams

Radiolarians

Red algae

Chlorophytes

Charophytes

Land plants

Slime molds

Gymnamoebas

Entamoebas

Nucleariids

Fungi

Choanoflagellates

Animals

Alveolates

Stramenopiles

Green

algae

Am

oebozoansO

pisthokonts

ExcavataC

hromalveolata

Rhizaria

Archaeplastida

Unikonta

SAR clade (10th ed)

Diplomonads (28.2) Excavata clade – 8th-10th ed.

– Two nuclei– “excavated” feeding groove on

one side– Multiple flagella– Usually anaerobic

• Due to their modified mitochondria that lack ETCs & don’t use O2 in respiration

– E.g. Giardia • Intestinal parasite• Contaminates streams• Causes severe diarrhea

Kinetoplastids (28.7)Excavata clade – 9 & 10 ed. Euglenozoan subclade

• Kinetoplast– DNA in mitochondria

• E.g. Trypanosoma• Blood parasite• Single encased flagellum• African Tsetse fly

– Sleeping sickness (attacks nervous system; lethargy; death if untreated)

• So.Amer. Kissing bugs– Chagas disease

Forams & Radiolarians (28.18)

Rhizaria clade – 9 & 10 ed.–Threadlike pseudopods for movement and food capture

• Foraminiferans– Have a CaCO3 shell– Thin extended pseudopods– Planktonic or benthic– Adds to the calcareous

sediments

• Radiolarians– Silica shells– thin pseudopods (axopodia or

actinopods)– Planktonic– Comprises silicious sediments

Ciliates (28.17) Chromalveolata clade – 8 & 9 ed. Alveolates subclade – 9 & 10 ed.

Alveoli (vacuoles) under plasma membrane - contractile vacuoles

– osmoregulation

•Cilia to move and feed– E.g. Paramecium, Stentor,

Vorticella•Two nuclei types

– Macronucleus• Everyday activities

– Micronuclei• Sexual reproduction

Apicomplexans Chromalveolata clade – 8 & 9 ed. Alveolates subclade – 9 & 10 ed.

• Parasites• Apex structures for penetrating

host cells• Lack cilia, flagella, or

pseudopods• E.g. Plasmodium

– Malaria– Enters and feeds on red blood

cells– Vector = ♀ mosquitoes

Dinoflagellates Chromalveolata clade – 8 & 9 ed. Alveolates subclade – 9 & 10 ed.

• Two flagella in grooves– Spinning flagellates

• Planktonic– Aquatic surface drifters

• Phytoplankton– Photosynthesizing – Red tides

• carotenoid pigments along with chl a

– Some are Mixotrophic– Some are Heterotrophic– Some are toxic

• Shell fish accumulation– Bioluminescence

Diatoms Stramenopiles subclade

(some stage with “hairy” flagellum)

• Photoautotrophic (phytoplankton)• Silica cell wall

– Glass-like– Two halves like a petri plate

• Shells sink after death and accumulate as sediments

• Diatomaceaous earth

• Diatom reproduction• Unique to cell structure• Mitotically divide the halves• Secretes the smaller half• Nucleus triggers meiosis when

too small

Multicellular Protists (algae)• More photoautotrophic

protistans… known as:– Algae, seaweed, kelp– Thalli may be filamentous, grow in

mats or crusts, sheets, or kelp• “ Plant-like” primary producers,

but not plants:– Lack true leaves, stems & roots

• Organized by pigment variations– Phaeophyta (browns)– Rhodophyta (reds)– Chlorophyta (greens)

Phylogeny of the once 5 “super clades” of Eukaryotes… *currently consolidated into 4

See also: Summary Table on page 598 of text (Ch 28)

SAR clade (10th ed)

Phaeophyta• Brown/yellow pigment

– Fucoxanthin, some phycobilin, some carotenoids (& chl)

• Diverse morphologies– Simple, small individual to large &

complex (i.e. lengths up to 100m)• kelp forest communities

• Some exhibit rapid growth– 1 to 2 feet a day– Important source of algin

• Thickener, stabilizer, emulsifier in many products

Rhodophyta• Red pigments

– Phycoerythrin, Phycobilins, carotenoids

• As a group, expands to greater depths than other algae– Why?

• Includes some coralline algae– CaCO3 in cell walls

• Defense and structure• Important component of coral

reef environments• Filamentous or Encrusting

• Commercial uses– Source of carrageenan & agar

(emulsifiers & gel thickeners)• Food

– Nori (sushi wraps) from Porphyra

Chlorophyta

• Green pigments– Chl a & Chl b– Same as plants

• Diverse morphologies– Filamentous– Sheets– Spongy– Calcareous

• Important component of coral reef environments

Other Chlorophytan examples

• Colonial• plant-like

chloroplasts– Volvox– Ulothrix– Spyrogyra

Amoeboids (28.5) Unikonta clade – 9 & 10 ed. Amoebozoan subclade

• Lobate pseudopodia– extensions of the cell

• Locomotion• Feeding

• Various environments– Aquatic; parasitic; moist soils

• Some are fungal-like– Slime Molds