EUKARYA KINGDOM PROTISTA I

Origin of Eukaryote: The Endosymbiotic Theory (1960) Pages 229, 307

Prove: Endosymbiotic  Plastid and mitochondria have their own DNA & ribosome that are 70s not 80s  They divide in a way similar to Prokaryotes, lack microtubules  Their DNA is circular, naked  Their ribosome are sensitive to the same antibiotics that interfere with prokaryotes ribosome  Evidence of symbiotic relationship between bacteria & protists, marine invertebrates, algae & protozoan (Fig )  Mitochondria arose first (common to all Eukaryotes), from purple nonsulfur bacteria!

Meiosis & Life cycles  For meiosis see page 236  In eukaryote a diploid stage undergo meiosis to produce a haploid stage  These two stages alternate in three patterns Gametic meiosis: most animals & some protists ** Sporic meiosis (alternation of generations: plants & many algae** Zygotic meiosis: Fungi & some algae**

Gametic Meiosis Fertilization Gametes - + Meiosis (spermatogenesis) Diploid individual Zygote This cell undergo meiosis - gamete + Gamete e.g. Human & some protists

Sporic Meiosis Meiosis Fertilization spores - + Sporophyte (Diploid individual) Zygote - Gamete + Gamete Gametophyte (Haploid individuls) This cell undergo meiosis e.g. Plants

Reproductive Cycles Animals and Plants Adult ♀ Adult ♂ Egg Zygote Embryo 2n 1n Meiosis Fertilization Sperm Spore Gametophyte Sporophyte

Zygotic Meiosis Meiosis Fertilization Haploid cells - + Zygote - Gamete + Gamete Haploid individuals e.g. Fungi

Classification of the Protists  Protista is established to hold problematic species  Each algal group must have its own evolutionary line  Organisms of uncertain origin are paced in the Protista  Protista includes: Plant-like organisms but gametes & zygotes not protected Fungi-like organisms but have flagella & lack chitin in cell wall Animal-like organisms but no embryonic development

Ecology of Aquatic Algae  Marine algae & cyanobacteria form phytoplankton  Importance Important in carbon cycle (absorb ½ CO 2 produced by human activities) Transform CO 2 into (CH 2 O) n & CaCO 3 Cause algal blooms (red & brown tides) Increase sulfur oxides in our atmosphere

Lake Neatahwanta, Fulton, NY

Euglenoids: Phylum Euglenophyta  e.g. Euglena**  Like green algae, have chl(a), (b) & carotenoids suggesting a symbiotic relationship  Only 1/3 of the phylum has chloroplast, the rest are heterotrophic  Euglenoids occur in freshwater rich in organic matter

Euglena  Reproduce by mitosis & lengthwise

Plasmodial Slime Molds: Phylum Myxomycota  The name mold “thought to have a relation with fungi”  Seems to have no close relation to other organisms  Plasmodium: amoeboid body with no cell wall**  Phagocyte: heterotrophic

Sclerotium Plasmogamy

Oomycetes: Phylum Oomycota  They are not Fungi because Cell wall has cellulose-like polymers Chromosomes not highly condensed as in fungi spores are flagellated  They are saprobic, few are parasitic  Pathogens of Coca, pineapple, tomatoes, rubber, papayas, onions, citrus  e.g. the genus Plasmopara**  e.g. Phytophthora infestans (Late blight of potato)**

Downy mildew in Grapes: Plasmopara viticola Downy mildew in grapes, threaten the entire wine production in France (introduces from the States 1870)

Late Blight of Potato (Phytophthora infestans)  Responsible for the great famine of in Ireland

Dinoflagellates: Phylum Dinophyta  Mostly unicellular & biflagellate**  Have chl. a, c, & carotenoid  Important part of marine phytoplankton  Many produce toxins (red & brown tides)

Dinoflagellates Unique: flagella move within 2 groves Ceratium

Red tide in Texas Bay, Gymnodinium breve Red tide in Texas Bay, Gymnodinium breve

Diatoms: Phylum Bacillariophyta  Very important component of phytoplankton  Occur in huge # m/1 cm of a submerged rock (1/4 of total carbon fixed)  They lack flagella & have unique shells * Pennate diatoms: bilaterally symmetrical** * Centric diatoms: radially symmetrical** - Centric float better therefore more abundant

Pennate Diatoms

Diatoms: often compared to a shoe box and its lid (frustules) Cell wall has an outer layer of silica (glass) 3 µm Lower valve (the box) Upper valve (lid)

Chrysophytes: Phylum Chrysophyta  Have chl(a) & (c) masked with a golden-brown fucoxanthin (=chrysophyte)**  Mostly unicellular or colonial; flagellated  Found in fresh & salt water all over world  Reproduction is asexually by zoospores

Synura sp.