Lab #3

1. Lab #3 Protists

2. Protists • eukaryotic organisms originally placed into the Kingdom Protista • placed into this kingdom because they didn’t fit into the Plant, Fungi or Animal kingdoms • unicellular organisms + multicellular relatives like kelps and seaweeds • agreement that this kingdom should be abandoned • abandoned the kingdom method of classification • now use a Domain classification system • Eukarya • Archaea • Bacteria (Prokaryota) • now based on a combination of phylogeny (evolutionary history) and DNA, molecular analysis – place these organisms into the Domain Eukayra • place them into new clades based on DNA sequences • clade = group of species all of which are descended from one ancestral species, representing one phylogenetic group • the protists of Kingdom Protista is now belong to 5 major clades

3. The freshwater ciliate Stentor, a unicellular protozoan (LM) 100 µm 100 µm Ceratium tripos, a unicellular marine dinoflagellate (LM) 4 cm Delesseria Sanguinea, a multicellular marine red alga 500 µm Spirogyra, a filamentous freshwater green alga (insert LM) Protist Clades • A. Excavata • 1. Diplomonadida and Parabasalida • 2. Euglenozoa – Trypanosomes & Euglena • B. Chromoalveolata • 1. Alveolata • i. Dinoflagellates • ii. Apicomplexans • iii. Ciliates – Paramecium – prepared & living • 2. Stramenophiles • i. oomycetes • ii. diatoms – prepared & living • iii. golden algae • iv. brown algae - various samples • C. Rhizaria • 1. Cercozoa • i. Forams • 2. Radiolaria • i. Radiolarins • D. Unikonta • 1. Amoebozoa • i. Gymnoamoebas • ii. Enteroamoebas – Amoeba proteus • iii. Slime molds • 2. Opisthokonta • i. Fungi • ii. Animals • iii. Choanoflagellates • E. Archaeplastida • 1. Red algae –various samples • 2. Chlorophyta • i. Chlorophytes (Green Algae) – Spirogyra & Volvox • ii. Charophytes • iii. Plants

5. A. Clade Excavata2. Euglenozoa • Euglena • Phylum: Euglenozoa • 44 genera • 800 species • Genus: Euglena • unicellular, biflagellated • one is longer than the other – swimming? • fresh & salt water • autotrophic & heterotrophic • autotrophic – photosynthesis • heterotrophic - phagocytosis • photosynthetic • have chloroplasts very similar to green algae plants – surround by one more membrane • chloroplasts have pyrenoids– make starch called paramylon • pyrenoids are used to identify Euglenozoans • red eye spot – not light sensitive • used to filter light that will fall on the photoreceptor • contains carotenoid pigments • photoreceptor – light sensitive • participates in phototaxis • http://www.youtube.com/watch?NR=1&feature=fvwp&v=sYupCQT46cI • http://www.youtube.com/watch?v=jl0TzaWUQWk&feature=endscreen

6. Clade: ChromoalveolataA. Alveolata1. Ciliates • Paramecium caudatum • Phylum: Ciliophora • characterized by presence of alveoli just inside the plasma membrane • flattened vesicles that support the membrane and form a pellicle • unicellular & ciliated • cilia for locomotion – 12 body length/second • most are freshwater • e.g. pond water • oral groove with tongue-like cilia to bring in food (heterotrophic) • feed on bacteria, algae and yeasts • oral groove leads to a gullet – when enough food accumulates a portion breaks off as a food vacuole • vacuole combines with digestive enzymes from the cytoplasm • osmoregulation necessary due to hypotonicity of their environment • excess water expelled by contractile vacuole • 2 nuclei • http://www.youtube.com/watch?v=l9ymaSzcsdY • detachment of food vacuole: http://www.youtube.com/watch?v=fh_yjLppNAg

7. Clade: ChromoalveolataB. Stramenophiles1. Diatoms • Phylum: Heterokontophyta • 200 genera • 100,000 species • Class: Bacillariophyta • major group of algae - found in phytoplankton • autotrophic • unicellular • colonial forms are seen • chloroplasts are derived from red algae & are surrounded by 4 membranes • freshwater and marine • dead diatoms found as diatomaceous earth • cell wall embedded with silica =frustule • lids or valves are not the same size • two valves fit like a “shoebox” • three basic forms: • centric • pennate without a raphe (seam) • pennate with a raphe • asexual reproduction by binary fission • in some species – the daughter cells are smaller so the populations decreases in size with reproduction • sexual reproduction is possible • most are non-motile • sperm in some species are flagellate – move by gliding

8. Clade: ChromoalveolataB. Stramenophiles2. Brown Algae • Class Phyaeophyta • 1500-2000 species of most marine algae • largest and fastest growing of seaweeds • seaweed: macroscopic, microscopic and benthic (seafloor) algae • includes members of read, green and brown algae • include the kelps: large seaweed • brown algae in the order Laminariales • multicellular – differentiation into distinct tissues • unique among this phyla • autotrophic • chloroplasts - same as diatoms and other members of Phylum Heterokontophyta • contain chlorophyll a • also contain an accessory pigment = fucoxanthin (brown) • body: thallus • not a “plant” – lacks xylem and phloem • BUT have similar structures to vascular plants • a. hold fast – root-like • b. stipe – stem-like • 3 defined tissues: pith, cortex and epidermis • similar to those of vascular plants • may be missing in some species • c. lamina or blades – leaf-like • lamina often have in or near them = pneumatocysts • bladder-like structures for buoyancy = lift the lamina/blade to the water surface for photosynthesis • immense commercial value • algin – extracted sugars used as thickening agents in foods

9. Clade: UnikontaA. Amoebozoans1. Amoebas • Amoeba proteus • Phylum: Tubulinea • Genus: Amoeba • possess lobopodia • used for locomotion and feeding (phagocytosis) • heterotrophic – phagocytosis • “naked” – do not have a shell • http://www.youtube.com/watch?v=R9MRSoxxaAs

10. Clade: ArchaeaplastidaA. Red Algae • taxonomy is disputed – so no phylum • should be considered its own kingdom? • red algae are monophyletic • up to 10,000 species? probably about 5,000 species across 600 genera • Rhodophyta is considered a division • multicellular algae • include many seaweeds • mostly marine – some freshwater • like fresh water with good currents • sperm is non-motile – so water currents are essential for sexual reproduction • defined as algae without flagella at any stage in their life cycle • also no centrioles • autotrophic • photosynthesis via chlorophyll a • also have additional pigments – phycocyanin and phycoerythrin– that mask the green of the chlorophyll • phycoerythrin is fluorescent – used in the lab • sexual reproduction introduces the idea of alternation of generations • alternating between diploid and haploid multicellular forms – called sporophytes (n) and gametophytes (n) • coralline forms secrete calcium carbonate • essential components of coral reefs • double cell walls • outer cell wall used to make agar • inner cell wall made of cellulose • large commercial value • Japanese nori • agar • carragenons for food

11. Clade: ArchaeaplastidaA. Chlorophyta1. Chlorophytes • Spirogyra • Volvox • Chlamydomonas • classified under the polyphyletic clade Archaeaplastida • considered to be part of a superphylum called Viridiplantae • gives rise to the green algae (Chlorophyta) plus a group that gives rise to Charophytes and their relatives, the plants • 6,000 species • including Ulva“sea lettuce” • unicellular, colonial, filamentous and multicellular species • freshwater and marine • motile (via flagella) and non-motile • autotrophic: primary produces in aquatic ecosystems • defined (together with plants) as having chloroplasts with chlorophylls a and b and stacked thylakoid membranes • pyrenoid involved in amylase synthesis (starch) • many other similarities with land plants • reproduction shows alternation of generations • haploid algae cells fuse to one another using a bridge = conjugation • very rapid reproduction rates in some species • use as biofuels and livestock food? Sea lettuce