Domain Bacteria Domain Archaea Domain Eukarya Common ancestor Kingdom: Protists Domain Eukarya

General characteristics  Classification criteria  eukaryotes  not animal, plant or fungi That’s more of what they’re not & not what they are!

Great Diversity dinoflagellates & ciliates euglenoids brown algae & diatoms red algae green algae miscellaneous?

Problems with Protist Classification Euglenozoa Animals Streptophyta (includes land plants ) Choanoflagellida Fungi Chlorophyta Rhodophyta Stramenopila Alveolata Archaea Bacteria Something’s not right here!

How did Eukaryotes Evolve?

Theory of Endosymbiosis Ancestral eukaryotic cell Eukaryotic cell with mitochondrion internal membrane system aerobic bacterium mitochondrion chloroplast Eukaryotic cell with chloroplasts photosynthetic bacterium Paramecium & symbiont Chlorella

Protist Diversity  The full spectrum of modes of life  from unicellular to multicellular  autotrophic to heterotrophic  asexual to sexual reproduction  pathogenic to beneficial  sessile to mobile

Mobility  How Protists move  flagellum  cilia  pseudopod

Protist Diversity  Animal-like Protists  heterotrophs, predators  Amoeba  Paramecium  Stentor Paramecium with food vacuoles stained red Amoeba ingesting a Paramecium

Protist Diversity  Plant-like Protists  autotrophs, photosynthesis  Euglena  algae  diatoms

Protist Diversity  Parasitic & pathogenic Protists  malaria  Giardia  trypanosomes Plasmodium Giardia Trypanosoma

Protist Diversity  Beneficial & necessary Protists  small algae + diatoms  much of the world’s photosynthesis  produces ~90% of atmospheric oxygen  heterotrophic protists  key ecological role at base of marine food web

Kingdom: Euglenozoa  Have flagella  Phyla:  Euglenoids – may be autotrophic or heterotrophic  Kinetoplastids – symbiotic and may be parasitic, e.g. causes African Sleeping Sickness (bite of tsetse fly)

Kingdom Alveolata  Photosynthetic flagellates, parisitic group and ciliates combine to form this kingdom.  Dinoflagellates – phytoplankton, cause red tides, some are coral symbionts that produce for reef community

 Apicomplexans – all are parasitic, example plasmodium.  Ciliates – All have cilia to move and feed. 2 types of nuclei (Stentor, paramecium)  Macronucleus – have several ;everyday functions, asexual reproduction  Micronucleus – 1 for sexual reproduction

Stramenopila  Includes photosynthetic and heterotrophic organisms  All possess hairlike projections on flagella  Chloroplasts derived from secondary endosymbiosis  Diatoms (Bacillariophyta) – glass-like cell walls  Freshwater and marine plankton  Diatomaceous earth used for filtering and abrasive purposes

 Golden Algae (Chrysophyta) – carotene and xanthophyll accessory pigments  Freshwater and marine plankton  Oomycota – Oomycota –  White rust  Mildew  Water mold – on dead fish  All are fungus-like  Caused Irish potato famine, by destroying crops

 Phaeophyta – Brown algae Phaeophyta –  All are multicellular  Includes seaweeds  Seaweed adaptations:  Analogous plant-like structures  Body = thallus  Root-like structure – holdfast  Stem-like structure – stipe  Leaf-like structure - blades

Cercozoa and Radiolaria  Have threadlike pseudopodia  Actinopods – heliozoans and radiolariansradiolarians  Foraminiferans – mostly marine  Porous shells  Mostly fossils  White cliffs of Dover due to fossilized foraminiferans

Amoebozoa  Identify them by lobe shaped pseudopods  Phylum: Gymnamoebas – amoebasamoebas  Mitosis with persisting nuclear envelope  Asexual reproduction Entamoebas - parasitic, cause amoebic dysentery.

 Plasmodial Slime Molds – show cytoplasmic streaming  Multinucleated plasmodium in feeding stage  Cellular slime mold are haploid

Kingdom: Rhodophyta  No flagellated stage, evidence shows they lost flagella during evolution  Accessory pigment phycobillins  Color depends on depth  Found in deepest waters  Has carageenin – used in agar and agarose

Chlorophyta  Cellulose cell walls  Chl a is primary pigment  Starch as polysaccharide storage molecule Hmmm… What does that sound like

Examples of Green Algae  Chlamydomonas reproduce both sexually and asexually  Spirogyra – filamentous green algae, show both sexual and asexual reproduction  Volvox - colonial green algae

Traditional view of three domains

DNA analysis dictates that this is a more likely scenario

Multicellularity  Evolutionary novelty that broke into new adaptive zones occupied by larger organisms  Possibly derived from colonial aggregates  Cell specialization led to multicellularity  Led to plant, fungi and animal kingdoms

Any Questions??

Stramenopila  Includes photosynthetic and heterotrophic organisms  All possess hairlike projections on flagella  Chloroplasts derived from secondary endosymbiosis, possibly red algae  Diatoms (Bacillariophyta) – glass-like cell walls Diatoms  Freshwater and marine plankton  Diatomaceous earth used for filtering and abrasive purposes