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Eukaryotes Protista, Fungi, Plantae, Animalia Complex >10x larger
DNA in nucleus Cell membrane Some also have cell wall Membrane bound organelles specialization
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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
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Protistan origin 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
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Figure 28.3 Exploring: Protistan Diversity.
Diplomonads Parabasalids Euglenozoans Excavata Dinoflagellates Apicomplexans Ciliates Diatoms Golden algae Brown algae Oomycetes Alveolates Chromalveolata SAR clade (10th ed) Stramenopiles Cercozoans Forams Radiolarians Rhizaria Red algae Chlorophytes Charophytes Land plants Green algae Archaeplastida Figure 28.3 Exploring: Protistan Diversity. Slime molds Gymnamoebas Entamoebas Nucleariids Fungi Choanoflagellates Animals Amoebozoans Unikonta Opisthokonts Figure 28.2
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“…protist phylogeny continues to emerge… changing rapidly…”(Campbell 28.1)
Five Supergroups: Excavata Chromalveolata Rhizaria Archaeplastida Unikonta
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“…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” Algae non-plant, photosynthetic aquatic eukaryotes
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Figure 28.3 Exploring: Protistan Diversity.
Diplomonads Parabasalids Euglenozoans Excavata Dinoflagellates Apicomplexans Ciliates Diatoms Golden algae Brown algae Oomycetes Alveolates Chromalveolata SAR clade (10th ed) Stramenopiles Cercozoans Forams Radiolarians Rhizaria Red algae Chlorophytes Charophytes Land plants Green algae Archaeplastida Figure 28.3 Exploring: Protistan Diversity. Slime molds Gymnamoebas Entamoebas Nucleariids Fungi Choanoflagellates Animals Amoebozoans Unikonta Opisthokonts
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Diplomonads (28.2) Two nuclei “excavated” feeding groove on one side
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
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Kinetoplastids (28.7) Excavata clade – 9 & 10 ed. Euglenozoan subclade
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
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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
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Ciliates (28. 17) Chromalveolata clade – 8 & 9 ed
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
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Apicomplexans Chromalveolata clade – 8 & 9 ed
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
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Dinoflagellates Chromalveolata clade – 8 & 9 ed
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
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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
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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)
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Phylogeny of the once 5 “super clades” of Eukaryotes…
Phylogeny of the once 5 “super clades” of Eukaryotes… *currently consolidated into 4 SAR clade (10th ed) See also: Summary Table on page 598 of text (Ch 28)
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Phaeophyta Brown/yellow pigment Diverse morphologies
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
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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
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Chlorophyta Green pigments Diverse morphologies Chl a & Chl b
Same as plants Diverse morphologies Filamentous Sheets Spongy Calcareous Important component of coral reef environments
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Other Chlorophytan examples
Colonial plant-like chloroplasts Volvox Ulothrix Spyrogyra
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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
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