BIO 1150 1st Edition Lecture 18Chapter 27 Topic Discussed: ProtistsProtists- Eukaryotes with organelles and are more complex than prokaryotes- Most are unicellular, but there are some colonial and multicellular species- They exhibit more structural and functional diversity than any other group of eukaryotesNutritional strategies include:- Photoautotrophy- derive energy from light, contain chloroplasts and photosynthesize- Heterotrophy-absorb organic molecules or ingest larger food particles and require organicnutrients to make organic compounds- Mixotrophy- a combination of feeding modesEndosymbiosis in Eukaryotic Evolution- Endosymbiosis - process in which a unicellular organism engulfs another cell and becomes a permanent symbiont- Mitochondria- aerobic prokaryote- Plastids- photosynthetic cyanobacteriumFive Supergroups of Eukaryotes1. Excavata2. Chromalveolata3. Rhizaria4. Archaeplastida5. UnikontaSupergroup Excavates- modified mitochondria- unique flagella- Cytoskeleton- Clades: diplomonads, parabasalids, and euglenozoansDiplomonad and Parabasalid Clades- Lack plastids, have modified mitochondria- most live in anaerobic environmentsEuglenozoan Clade- includes predatory heterotrophs, photosynthetic autotrophs, and parasites- Have a spiral or crystalline rod of unknown function inside their flagella- Clade includes:kinetoplastids and euglenidsKinetoplastids- one mitochondrion with an organized mass of DNA called a kinetoplast- free-living consumers of prokaryotes in freshwater, marine, and moist terrestrial ecosystemsSupergroupChromalveolates- Origin- secondary endosymbiosis event with a red alga- Includes: alveolates and stramenopiles cladesAlveolate Clade- membrane-bounded sacs (alveoli) just under the plasma membrane- The alveolates include:o Dinoflagellateso Apicomplexanso CiliatesDinoflagellates- two flagella, each cell is reinforced by cellulose plates- Abundant components of phytoplankton causes “red tides”- A diverse group of aquatic phototrophs, mixotrophs, and heterotrophsCiliates- Use cilia to move/ feed- have large macronuclei and small micronuclei- Genetic variation results from conjugation- two individuals exchange haploid micronuclei- Paramecium=the classic ciliateStramenopile Clade- important phototrophs and several clades of heterotrophs (over 100,000 species)- have hairy and smooth flagellum- includes: diatoms, golden algae, brown algae, and oomycetesDiatoms (unicellular algae)- unique two-part, glass-like wall of hydrated silica- usually reproduce asexually, and occasionally sexually- diverseBrown Algae (ex. Kelp)- Largest/ most complex algae- Multicellular/mostly marine- photosynthetic- commonly called seaweeds- most complex multicellular anatomy of all algaeAlternation of Generations- alternation of multicellular haploid and diploid forms- The diploid sporophyte produces haploid flagellated zoospores- Zoospores develop into haploid male and female gametophytes, which produce gametes- Fertilization of gametes results in a diploid zygote, which grows into a new sporophyteOomycetes- water molds, white rusts, and downy mildews- decomposers or parasites with filaments (hyphae) for nutrient uptake- High ecological impacts like potato blight SupergroupRhizaria- DNA evidence supports Rhizaria as a monophyletic clade- Amoebas move/feed by pseudopodia (some belong to the Rhizaria)- Include:radiolarians, forams, and cercozoansForaminiferans- porous, multichambered tests (shells)- Pseudopodia extend through the pores in the test- endosymbiotic algae (most have)SupergroupArchaeplastida- 1+ billion years ago, a heterotrophic protest gained a cyanobacterial endosymbiont- photosynthetic descendants evolved into red algae and green algae- includes:red algae, green algae, and land plantsGreen Algae- paraphyletic group named for green chloroplasts- two main groups are chlorophytes and charophyceans- Charophytes- most closely related to land plantsChlorophytes- large size and complexity because:- colony formationfrom individual cells- formation of multicellular bodies by cell division and differentiation - repeated division of nuclei with no cytoplasmic divisionForaminiferans= majorcontributor for dissolved carbon in the oceanSupergroupUnikonta- animals, fungi, and some protists- includes: amoebozoans and opisthokontsclades- unclear whether unikonts separated from other eukaryotes relatively early or lateClade Amoebozoa- amoeba that have lobe/tube-shaped (not threadlike) pseudopodia- includes: slime molds, gymnamoebas, and entamoebas- Not fungi- Plasmodial and cellular forms- Plasmodial– brightly pigmented, yellow or orangeCellular Slime Molds- form multicellular aggregates in which cells are separated by their membranes- Cells feed individually, can aggregate to form a fruiting body- Dictyosteliumdiscoideumis an experimental model for studying the evolution of