Major Eukaryotic Clades Student Learning Objectives Explain the endosymbiotic hypothesis and origin of the eukaryotes List at least one synapomorphy and give examples of the major clades Amoebozoa Opisthokonta Discoba Archaeplastida Rhizaria Stramenopila Alveolata List at least one synapomorphy and give examples of the major clades Archaeplastida Rhizaria Alveolata and Stramenopila Describe the morphological and evolutionary diversity among the organisms called algae Explain the origins of the primary and secondary plastids Members of the bacteria and archaea generally lack organelles and are smaller than eukaryotes Called prokaryotes before nucleus So prokaryote does not refer to a monophyletic group Bacteria and Archaea have DNA a single circular chromosome in most types nucleus and other organelles Homeostasis Metabolism Mechanism for Heredity Reproduction Behavior EUKARYA ARCHAEA BACTERIA Origins of the eukaryotes What did the proto eukaryote look like Maybe looked like Pelomyxa palustris 1 Single celled 2 Much larger than bacteria 3 Possessed a nucleus and cytoskeleton 4 No cell walls 5 Lived in oxygen poor environments 6 Lacked mitochondria What are mitochondria Organelle where electron transport chain produces ATP Complex membrane structure high H produced in matrix runs ATP synthase Also contains multiple copies of a small circular chromosome This mtDNA has genes for proteins used within the mitochondria Other mitochondrial proteins are coded for by DNA in the nucleus Maternally inherited Endosymbiotic theory animals fungi amoebozoa discobans SAR time endosymbionts mitochondria time a proteo bacteria pre eukaryote plants A pre eukaryote engulfed a bacterium capable of doing aerobic respiration producing much more ATP per unit of food intake Symbiotic relationship establishes Eukaryote provides protection and sugars Bacterium supplies ATP The symbiotic bacterium became the mitochondrion and that pre eukaryote was the ancestor to all eukaryotes Endosymbiotic theory Ridiculed Within Eukaryotes hypothesis Mitochondria evolved inside the eukaryotic cells What is your prediction DNA of mitochondria should be more closely related to Endosymbiotic hypothesis Mitochondria were originally free living bacteria that eventually established symbiotic relationships with a proto eukaryote What is your prediction DNA of mitochondria should be more closely related to Lynn Margulis 1970 Which hypothesis was correct Endosymbiotic theory supported Now called theory because hundreds of experiments support this hypothesis Land plants Hepaticophyta Bryophyta Anthocerophyta Lycophyta Pteridophyta Gymnosperms Angiosperms Fungi Chytridiomycota Zygomycota Glomeromycota Ascomycota Basidiomycota Animals Porifera Cnidaria Mollusca Annelida Platyhelminthes Nematoda Arthropoda Echinodermata Chordata Major Clade Discoba have disc shaped cristae in their mitochondria Arrows point to the disk shaped cristae in mitochondria of Eutreptia pertyi Discoba Kingdom Euglenids Numerous feeding modes Autotrophic chloroplast from endosymbiosis with a green alga Heterotrophic Diverse life styles Free living Parasitic Reproduce by binary fission Discoba Euglenozoa Anterior flagella Feeding groove Kingdom Euglenids Trypanosoma brucei causes sleeping sickness in humans and livestock carried by tsetse fly present but infection rates down by at least 90 Distribution of human African trypanosomiasis Trypanosoma brucei and red blood cells Source MicrobeWiki Tsetse fly vector Kingdom Euglenids Trypanosoma cruzi causes Chagas disease carried by ruduviid bugs First stage of disease Romana s sign Distribution of human Chagas disease In the United States the economic burden of Chagas disease is comparable to the burden of much more publicized infectious diseases such as Lyme disease Feb 7 2013 The Lancet Infectious Diseases Ruduviid bug vector Major Clade Amoebozoa amoeboid morphology feed via lobe like pseudopodia 3 groups of Amoebozoa Lobose amoebas Cellular slime molds Plasmodial slime molds Kingdom Lobose amoeba Free living Terrestrial and aquatic Single cell Relatively small Primarily heterotrophs Kingdom Plasmodial slime molds No cell wall Vegetative phase is a plasmodium one giant amoeba Fruiting structure is a sporangium Formed from a single plasmodium Generate spores Sporangia may be very elaborate and ornate Once included with the fungi Kingdom Cellular slime molds Live in fresh water damp soil and rotting vegetation downed logs Vegetative state is a free living amoeba Under certain conditions amoebae aggregate to form a slug Cheating vs cooperation Life cycle of a cellular slime mold Is dart a cellular slime mold Major Clade Opisthokonta flat cristae in mitochondria single posterior flagellum 3 groups we will study Choanoflagellate Fungi Animals Kingdom Choanoflagellates sister group to the animals Choanoflagellates Platyhelminthes Porifera sponges Cnidaria Ctenophora Annelida Mollusca Arthropoda Nematoda Chordata Echinodermata Kingdom Choanoflagellates sessile some are colonial aquatic suspension feeders Individual cells embedded in a gelatinous matrix Coordinated flagellar movements Water current Choanoflagellate cell Food particles Figure 31 11a Biological Science 2 e 2005 Pearson Prentice Hall Inc Major Clade Metamonada many body plans often with multiple flagella in clusters of 3 4 2 groups of Metamonada Diplomonads Giardia lamblia Parabasalids Trichomonas sp Kingdom Diplomonads Most are parasites Giardia cysts found in fecal contamination especially in beaver ponds can cause dysentery and diarrhea Serious threat for campers Giardia lamblia Cysts are dormant forms that shut down metabolism and have a resistant covering Kingdom Parabasalids Often involved in symbioses Trichomonas vaginalis urogenital tract infections in humans Females low birth weight Increased susceptibility to HIV Males Linked to aggressive prostate cancer Trichonympha Termite symbiote Bacterial endosymbionts in Trichonympha produce cellulase Trichomonas sp Trichonympha spp Obligate mutualisms Algae are photosynthetic eukaryotes that are not land plants and they are not a monophyletic group Algae is a term that describes a growth form and life style but does not imply relatedness among the members Why should we care about algae Base of all aquatic food chains freshwater and marine Algae are more morphologically complex than you probably think Why should we care about algae Algae may save our bacon fuel wise Cheaper and more easily grown source