protistan clades ch 28
TRANSCRIPT
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