BIOL 112 1st Edition Lec-ture 12 Outline of Last Lecture I. HeterotrophyII. Systematics/TaxonomyIII. Three DomainsIV.Domain ArchaeaV. Domain BacteriaVI.Recent Historical TrendsVII. Distinguishing Characteristics of EukaryaVIII. Endosymbiont TheoryIX.Sequence of Endosymbiotic EventsOutline of Current LectureX. Chloroplasts: A Second EndosymbiosisXI.Modern ProtistansXII. Traditional GroupingsXIII. General Eukaryotic Life CycleXIV. TermsXV. Domain EukaryaXVI. Supergroup ExcavataXVII. AlveolataXVIII. ApicomplexansXIX. StamenopilaXX. OomycotaThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.XXI. Supergroup ArchaeplastidaXXII. AnimalsXXIII. Body Plan Criteria for Organizing AnimalsXXIV. Digestive SystemCurrent LectureI. Chloroplasts: A Second Endosymbiosis•Molecular homologies link most chloroplast genomes most closely tocyanobacteria (blue-green algae)•This could mean that most modern chloroplasts arose from one orig-inal cyanobacterial-like ancestor, or that several times with closely-related cyanobacteria.•Closest candidate for chloroplast ancestor is called Prochlorothrix, an aerobic cyanobacteria with both chlorophyll a and b.•Combination of alga and cell now could do Hill Reaction and Calvin Cycle•As with mitochondria, over time, symbiont genes were progressively transferred into host cell genome so that modern chloroplast genome is minimal•An additional feature of this model is the hypothesis that some eu-karyotic algae could become symbionts themselves with other eu-karyotic hosts: Secondary Endosymbiosis•Symbiont loses all but its chloroplast function and its plasma mem-brane over time, because all other functions are duplicated by host•Detectable because chloroplasts are surrounded by extra mem-branesII. Modern Protistans•Systematics are constantly changing•No universally agreed system of number of kingdoms or number of phyla or bases of defining criteria•Revisions/debates drain by mass of new data, especially molecular sequence information•These lectures are based on Campbell's scheme, but be aware of thetentative nature of thisIII. Traditional Groupings•Used to be sub-Kingdoms, but not anymore•One approach, informal groupings:•Animal-like Protists - protozoa•Plant-like Protists - algae•Fungus-like Protists - slime molds•These categories defined general lifestyle and nutrition characteris-tics•Representatives in each group might resemble forms ancestral to the 3 major multicellular kingdomsIV.General Eukaryotic Life Cycle•Alternation between haploid and diploid phases of life cycle, with sexual events (meiosis and fertilization) between phases. The X scheme.•Diploid Phase -- 2n -- "sporophyte": phase of meiosis and spore for-mation•Haploid Phase -- n -- "gametophyte": phase of gamete formation for fertilization•Some species emphasize one phase over the other, others have ex-tended periods of existence in both phases (i.e. haploid or diploid dominant and the other reduced)V. Terms•If haploid and diploid phases look identical, then this is an isomor-phic generation species•If haploid and diploid phase organisms look very different from one another, then this is a heteromorphic generation species•Types of gametes also differ:•Isogamy: Both gametes are same size and appearance; both fre-quently motile, considered a primitive condition•Anisogamy: One gamete larger than the other; both still motile•Oogamy: One gamete huge, non-motile (egg), the other small and motile (sperm)VI.Domain Eukarya•All the eukaryotes: protistan Kingdoms and the three "crown group" Kingdoms•11 or more Kingdoms in the tentative scheme in Campbell•Defined/distinguished by molecular sequence divergence/homology, especially for rDNA sequences, and also some phenotypic characters•Some have more than one phylum; others only one phylum per king-dom•Some groups not yet considered or organizedVII. Supergroup Excavata•Possibly three kingdoms: Diplomonads, Parabasilids, Euglenozoans•Originally diplomonads thought to have been pre-mitochondrial eu-karyotes•Now shown to have mitochondrial genes, so they must have lost mitochondria instead•Nevertheless, very primitive forms: symbiotic (mostly parasitic), no mitochondria, poorly•Diplomonads: Giardia lamblia, “hiker’s diarrhea”•Parabasalids: Trichomonas vaginalis, human female infection; hyper-mastigids, termite gut symbionts, eat and digest wood for insect•Euglenozoans: EuglenaVIII. Alveolata•All members possess alveoli (fluid-filled sacs just under the plasma membrane), function unknown•Also unified by molecular homologies of rDNA sequences•Three phyla:•Dinoflagellates•Apicomplexans (Sporozoa)•CiliatesIX.ApicomplexansAlso known as Sporozoans; all parasitic, many with complex life cy-cles; common formsAll members have characteristic apical complex. Function: might help parasite cell attach to and invade host cellLife cycles are very complex because they frequently involve two or three different host organisms. Commonly alternate between inverte-brate (insect, crustacean, etc.) and vertebrate hosts, and sexual [in-vertebrate host] and asexual [vertebrate host] phases.Ex: malaria, toxoplasmaX. Stamenopila•Defined by possession of hair-like projections on flagella: stra-menopiles•Four phyla in kingdom:•Oomycota: water molds, rusts, mildews•Diatoms: walls made of silica•Golden Algae•Brown Algae: Kelps•Water molds are strictly heterotrophic, many parasitic•Other groups are photosyntheticXI.Oomycota•Water Molds, mildews•Superficially similar to fungi: mycelia, spores, heterotrophic, decom-poser nutrition•But significant differences: cellulose cell walls, flagellated zoospores, diploid-dominant life cycle as well as molecular differences•Fluffy masses on dead or diseased tissues•Some species parasitic: Phytophthora infestans, cause of Irish Potato Blight that started Potato Famine -- disruption of Irish culture in 1840sXII. Supergroup ArchaeplastidaRhodophytes and Green AlgaePossibly ancestral to K. PlantaeUnified by details of chloroplast structure and genomic contentIncludes Carophyceans -- advanced algae, possible immediate ances-tors to plantsK. Rhodophyta•Red algae•Red color from accessory pigment (phycoerythrin)•Lack any flagellated stage in life cycle. Gametes must rely on watercurrents to find each other•Some species can live at