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What are the common characteristics of Protists?
- Most abundant in moist habitats
- Most are microscopic in sizes
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What are three major groups of Protist?
- Algae- generally photoautotrophic
- Protozoa- heterotrophic
- Fungus-Like - resemble fungi in body form and absorptive nutrition
- IE: Convergent evolution
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What is Plankton?
Swimming or floating
- Phytoplankton-photosynthetic
- Protozoan plankton - hetertrophic
Occur as single cells, colonies or short filaments.
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What is Periphyton?
- Attached by mucilage to underwear surfaces
- Produce multicellular bodies
- Seaweeds or Macroalgae
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Classified by motility:
a) Swim
b) Cilia
c) Amoeboid Movement
d) Gliding
- a) using eukaryotic
- b) shorter and more abundant than flagella (ie: Ciliates)
- c) using pseudopodia (ie: Amoebae)
- d) on protein or carbohydrate slime
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Supergrp Excavata
Trichomonas vaginalis
Giardia lamblia
- *Name for feeding groove "excavated" into the cells of many respresentatives
- *Food particles are taken into cells by phagotrophy (Endocytosis and evolutionary basis for endosymbiosis)
- * thought to lack mitochandria; but do possess highly modified mitochandria
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Supergrp Excavata
Euglenozoa
- Interlocking protein strips beneath PM
- * can crawl through mud
- Some hetertophic
Euglena-photosynthetic
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Supergrp Excavata
Kinetoplastids
Large mass of DNA (kinoplasts) in single lg mitochondrion
- Leishmania
- Trypansosoma brucei
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Supergrp of plants and relative:
Kingdom Plantae:
Phylum Chlorophyta:
Phylum Rhodophyta:
Phylum Haptophyta:
Phylum Cryptophyta:
- KP: land plants evolved from green algal ancestors
- PC: Green Algae
- PR: Red Algae
- PH: Dover Cliff
- PC: Unicellular Flagellates
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Green Algae
- Diverse Structual types
- Occur in fresh waters, ocean and on land
- Most r Photosynthetic
- Cells contains same type of plastids and phosyn pigments as r present in land plants
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Red Algae
- Most r multicellular marine macroalgae
- Red appearence due to distinctive photosyn
- Lack flagella
- Unusually complex life cycle: hv primary plastids derived from cyanobacteria
- plastids have two envelope membranes
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Cryptomonads
- Unicellular flagellates
- Contain red, blue-green, or brown plastids
- Photosynthetic
- Hv more than 2 envelopes
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Haptophytes
- Primarily unicellular marine photosynizer
- Hv more than 2 envelopes
- Known as coccolithophorids covering of white calcium carbonate discs called coccoliths (Dover Cliff)
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Supergrp Alveolata
Cillophora
Apicomplexa
Dinozoa
- C: Ciliates-Conjugation
- A: Medically impt parasites
- Plasmodium
- Red tide and mutualistic relationship w coral;
- Named for saclike membranous vesicle (alveoli)
- Hv tertiary plastids
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Supergrp Stramenopila
- Wide range of algae, protozoa, and fungus like protists
- Produce flagellate cells at some point
- Named for strawlike hairs on the surface of flagella
- Heterotrophic or photosynthetic
- Plastids from 2o endosymbiosis w red algae
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Supergrp Rhizaria
Hv thin, hairlike extensions of the cytoplasm called filose pseudopodia
- Phylum Chlorarachniophyta
- Phylum Radiolaria
- Phylum Foraminifera
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Supergrp Amoeboza
- Many types of Amoebae
- Move using pseudopodia
Entamoeba Histolytica
Slime molds
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Supergrp Opisthokonta
Incl. animal and fungal kingdoms and related protists
Named for single posterior flagellum or swimming cells
Choanoflagellate Protists
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4 Basic types of Nutrition
Phagotrophy
Osmotrophy
Photoautotrophy
Mixtrophy
- P: heterotrophs that ingest particles
- O: heterotrophs that rely on uptake of small organic molecules
- Photo: photosynthetic
- M: able to use autotrophy and phagotrophy or osmotrophy depending on conditions
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Algal Protists
- Variety of pigments:
- Adapt photosystems to capture more lights
- Water absorbs the longer red and yell wavelengths more than blue and green
- Accessory pigm absorb light and transfer it to chlorophyll AVaritey of food storage molecules:
- Starch, polysacchrides and oils
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Defense
- Slimy mucilage or cell walls defend agnst herbivores and pathogens
- Trichocysts r spear-shaped projectiles to discourage herbivores
- Bioluminescence- startle herbivores
- Toxins- inhibit animal physiology (Pfiesteria)
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Asexual Reproductions:
- All Protists can produce asexually
- Produce cysts with thick, protective walls that dormant in bad conditions
- Protozoan pathogens spread from one host to other via cysts
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Sexual Reproductions:
- Eukaryotic sexual reprod w gametes and zygotes arose among protists
- Adaptives bc it produces diverse genotypes
- Zygotic and sporic life cycles
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Zygotic Life Cycle:
- Unicellular sexually reproducing protists
- Haploid cells develop into gametes
- + and - mating strains
- Thick walled diploid zygotes(Survive like cysts)
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Sporic Life Cycle:
- Multicellular green and brown seaweeds
- Known as alternation of generations
- 2 Types multicellular organisms:
- Haploid gametophyte produces gametes
- Diploid sporophyte produces spores by meiosis
- Red Seaweed involves 3 distinct multicellular generations
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Gametic Life Cycle:
- All cells except gametes r diploid
- Gametes produced by meiosis
- Diatoms r one of the few protists w this life cycle
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Ciliate Sexual Reproduction -Conjugation
- Most complex sexual process in protists
- Hv two types of nuclei( single macronucleus and one or more micronuclei)
- Macronucei r source of info for cell fxn
- 2 cells pair and fuse - conjugation
- Micronuclei undergo meiosis, exchange, fusion and mitosis
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Parasitic protist life cycle
- Parasitic protists often use more than one host organism in which different life stages occur
- Malarial parasite Plasmodium alternate bwn humans and anopheles mosquitos
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