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.