eukarya kingdom protista i. origin of eukaryote: the endosymbiotic theory (1960) pages 229, 307
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EUKARYA
KINGDOM PROTISTA I
Origin of Eukaryote: The Origin of Eukaryote: The Endosymbiotic Theory (1960)Endosymbiotic Theory (1960)
Pages 229, 307
Prove: EndosymbioticProve: 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. 12-11)
Mitochondria arose first (common to all Eukaryotes), from purple nonsulfur bacteria!
Meiosis & Life cyclesMeiosis & 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 MeiosisGametic Meiosis
FertilizationGametes- + - +
Meiosis (spermatogenesis)
Diploid individual
Zygote
This cell undergo meiosis
- gamete+ Gamete
e.g. Human & some protists
Sporic MeiosisSporic Meiosis
MeiosisFertilizationspores
- + - +
Sporophyte(Diploid individual)
Zygote
- Gamete+ Gamete
Gametophyte(Haploid individuls)
This cell undergo meiosis
e.g. Plants
Reproductive CyclesReproductive CyclesAnimals and PlantsAnimals and Plants
Adult ♀
Adult ♂
Egg
Zygote
Embryo
2n
1n
Meiosis
Fertilization
Sperm
Spore GametophyteSporophyte
Zygotic MeiosisZygotic Meiosis
MeiosisFertilization
Haploid cells- + - +
Zygote
- Gamete+ Gamete
Haploid individuals
e.g. Fungi
Classification of the ProtistsClassification 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 AlgaeEcology of Aquatic Algae
Marine algae & cyanobacteria form phytoplankton Importance
Important in carbon cycle (absorb ½ CO2 produced by human activities)
Transform CO2 into (CH2O)n & CaCO3
Cause algal blooms (red & brown tides)Increase sulfur oxides in our atmosphere
Lake Neatahwanta, Fulton, NY
Euglenoids: Phylum Euglenoids: Phylum EuglenophytaEuglenophyta
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
EuglenaEuglena
Reproduce by mitosis & lengthwise
Plasmodial Slime Molds: Plasmodial Slime Molds: Phylum MyxomycotaPhylum 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 OomycotaOomycetes: Phylum Oomycota
They are not Fungi becauseCell wall has cellulose-like polymers Chromosomes not highly condensed as in fungispores 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: Downy mildew in Grapes: Plasmopara viticolaPlasmopara viticola
Downy mildew in grapes, threaten the entire wine production in France (introduces from the States 1870)
http://www.inra.fr/Internet/Produits/HYP3/pathogene/3plavit.htm#det
Late Blight of PotatoLate Blight of Potato (Phytophthora infestans)(Phytophthora infestans)
Responsible for the great famine of 1846-47 in Ireland
Dinoflagellates: Phylum DinophytaDinoflagellates: Phylum Dinophyta
Mostly unicellular & biflagellate Have chl. a, c, & carotenoid Important part of marine phytoplankton Many produce toxins (red & brown tides)
DinoflagellatesDinoflagellates
Unique: flagella move within 2 groves
Ceratium
http://www.microscopy-uk.org.uk/mag/artsep01/dinof2.html
Red tide in Texas Bay, Gymnodinium breve
Diatoms: Phylum BacillariophytaDiatoms: Phylum Bacillariophyta
Very important component of phytoplankton Occur in huge # 30-50 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 DiatomsPennate Diatoms
Diatoms: often compared to a shoe box and its lid (frustules)
Cell wall has an outer layer of silica (glass)
3 µ
m
Lower valve (the box) Upper valve (lid)
Chrysophytes: Phylum Chrysophytes: Phylum ChrysophytaChrysophyta
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.Synura sp.
http://www.spea.indiana.edu/e455-jones/synura.jpg