Unit 1 bio182

Protist Functions

 1) Help maintain ecological balance  2) Food source  3) Supply oxygen  4) Some are economically important  5) Some cause disease

SuperPhylum Alveolata

 Alveolates have alveoli  flattened vesicles under plasma membrane  contain cellulose plates with cilicates  Ciliates (alveolate)  Move by hair-like cilia  Able to change shape due to flexible pellicle (covering)  2 kinds of nuclei  micronuclei - for sexual reproduction  macronuclei - for cell metabolism and growth  undergo complex sexual reproduction (conjugation)

Phylum Cercozoa

 Amoeboid-like cells  preditors - bacteria, algae, fungi  Often have hard outer shells (tests)  through which cytoplasmic projections extend  Foraminiferans (cercozoa)  Secrete many-chambered chalky tests (outer shell)  Pores - cytoplasmic projections extend  to move and obtain food

Protist Nutrtion:

 Autotrophic  Ex: Algae are photosynthetic  Heterotrophic  Ex: Amoeba ingest or engulf food  Some exhibit both autotrophic & heterotrophic characteristics  Ex: Euglenoids

Relationships Among Protists

 Determined by:  Fine details of cell structure  comparative molecular data ** in other words... determined by electron microscopy  Protista kingdom  Monophyletic group - evolved from common ancestor (electron microscopy)  Paraphyletic group - contains some, but not all of the descendants of a common eukaryotic ancestor (biologists)  The process of unraveling phylogenetic relationships is difficult and ongoing. Some relationships remain unclear.

SubPhylum Euglenoid

 Euglenoids (discicristates)  with disc shaped cristae in mitochondria  are unicellular with flagella  One long and whip-like & one short (within cell)  most live in shallow fresh water  some are photosynthetic  may lose chlorophyll if grown in dark  reproduce asexually  some change shape (Pellicle is flexable)  Ex: Euglena gracilis

Phylum Chrysophyta Golden Algae

 Found in both freshwater & marine environments.  Most are unicellular, biflagellate  Tiny scales (silica or calcium carbonate) cover the cells  Asexual reproduction

Discicristates

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Foraminiferans

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SubPhylum Diplomonad

Diplomonads (excavates)  with a deep (excavated) oral groove  Live in oxygen free environments  Obtain energy by anaerobic pathway of glycolsis  Diplomonads have:  one or two nuclei  no functional mitochondria  no Golgi complex  up to eight flagella  EX: Giardia intestinalis - causes backpackers' diarrhea

Protists

diverse group of eukaryotic organisms that mainly live in aquatic environments.

Phylum Amoebozoa (slime mold)

 Have characteristics like many other kingdoms  plant, animal, fungi  Amoebas  Use cytoplasmic extensions (pseudopodia)  mainly found in fresh water  to move and obtain food  Entamoeba histolytica  parasitic amoeba - causes dysentery

Super Phylum Heterokonts

 Heterokonts  Most have motile cells with two different kinds of flagella (may have hair-like projections).  Ex: water molds, diatoms, golden & brown algae  SubPhylum Oomycotes (Water molds)  A body called mycelium, grows over dead organic material. Digesting and then absorbing it.  reproduce both asexually & sexually  Root rot, mildew, blights  Phytophthora ramorum  Causes sudden oak death (CA & OR)  Also attacks redwoods, firs, bay trees, maples, etc.  Phytophthora infestans  causes late blight of potato

Phylum Zooflagellate

 Mainly unicellular heterotrophs, with spherical or elongated bodies  Move rapidly  Whip-like flagella  Ingest food  Mouth or oral groove  Polyphyletic  separated into several monophyletic groups  Excavates = Diplomonads & other zooflagellates  Discicristates = Euglenoids & other zooflagellates

Protist Interactions:

 Most Protista are free-living  Symbiotic relationships range from mutualism to parasitism  Mutualism = both benefit  Commensalism = one benefits and the other is unaffected  Parasitism = one lives on or in the other ** symbiosis - intimate relationship between species

Protist Habitats:

 Most protists live in aquatic environments  oceans  freshwater ponds  lakes  streams  Ex: plankton - base of food web in aquatic ecosystems  Some live in moist terrestrial environment  rocks near waters edge, soil cracks in bark, & leaf litter.  Parasitic protists live in body fluids of hosts

Protist reproduction

 Most protists reproduce both sexually and asexually  Some reproduce only asexually

Phylum Actinopoda

 Mostly marine plankton  Obtain food with axopods  slender cytoplasmic projections that extend through pores in shells  Radiolarians  actinopods with glassy shells Plankton food source

Red Algae

 Mostly multicellular seaweeds  important in warm tropical ocean waters  Sexual reproduction  No flagellate cells  Food source - high in vitamins A&C  Eaten fresh, dried or toasted (sushi & nori)  Cell walls:  Some contain thick sticky polysaccharides that have commercial value  Agar - food thickener, culture medium  Some red algae incorporate calcium carbonate in cell walls  important in reef building

Phylum Chrysophyta (Diatoms)

 Mostly unicellular algae, few exist as colonies  Cell wall consists of two overlapping shells containing silica (glass-like material)  Shells separate during asexual reproduction  Generations may get smaller  Two groups:  One with radial symmetry (wheel shaped)  One with bilateral symmetry (boat shaped)  Intricate patterns  major producers in aquatic ecosystems  Stores energy as oil or water-soluble carbohydrate  photosynthetic  Some are part of floating plankton  Some live on rocks and sediments  move by gliding

Phylum Phaeophyta Brown Algae

 Multicellular  important in cooler ocean waters  Kelps (giants of the protist kingdom)  Leaf-like blades - most photosynthesis occurs  Stipes - stem-like  Holdfasts - anchoring roots  Gas-filled bladders - for buoyancy

Protist Locomotion

 Pseudopodia (false feet) - move by pushing out and pulling in cytoplasmic extensions.  Flagella - "whip-like" organelle  Cilia - "hair-like" organelle  Some are sessile (nonmotile)

Alveolates-Dinoflagellates

 Sub phylum:  (aveolate)  Most are unicellular, some are colonial  Biflagellate  propel through water like a top  photosynthetic  major producers in marine ecosystems  Store energy reserves as oils or polysaccharides  Some are endosymbionts = live in the bodies of marine invertebrates  Mollusks, jellyfish, and corals  Some produce toxic blooms (red tides)

Alveolates-Apicomplexans

 Sub phylum:  are spore-forming parasites  lack structures for locomotion  cause disease  Apical complex of microtubules  attaches apicomplexan to host cell  Half of life cycle is spent in one host and the other half is spent in another host.  Mosquito = vector for transport  Human  Plasmodium  4 species cause malaria

Disease causing Euglenoids

 Trypanosoma brucei  causes African sleeping sickness  transmitted by titsi fly, only on African Continent  Trypanosoma Cruzi  Causes Chagas' disease  Transmitted by Triatomine bug feces, mainly in pour rural Latin America  NPI (neglected parasitic infection),a group of five parasitic diseases that have been targeted by CDC for public health action.  Leishmania  Causes leishmaniasis  Transmitted by sand fly, 90 different coastal countries

Protist types:

 Type:  Most Unicellular  microscopic  Colonies  loosely connected groups of cells  Coenocytes  multinucleated  Multicellular organisms  composed of many cells

Green Algae

 Wide diversity  in size, structural complexity, and reproduction  Body type:  single celled, colonial, multinucleated, and multicellular forming sheets  They are photosynthetic  Some have flagellate cells & some are nonmotile  Energy reserves are stored as starch  Found in both aquatic and terrestrial environments.