HP Lecture 4

• Phylogeny

  • evolutionary relatedness
• Clades: gps of organsim descended from the same original ancestor
• Binomial nomenclature

  • carl linnaeus 1735
  • plantae, animalia, minerals
  • unique genus and species name
• 5 kingdoms- Whittaker 1969

  • monera, protista, plantae, fungi, animalia
• 2 superkingdoms- Cavalier-smith 1998

  • prokaryota, eukaryota
• Protozoa classification

  • microscope- motility
  • otto butschli 1880
  • sarcodina, mastigophora, sporozoa, infusoria
  • later changes: combine 1st 2 to form sarcomastigophora; split the 3rd to apicomplexa and microsporidia
• Endosymbiont theory: margulis 1967; origin of eukaryotes
• asgard archaea: thor, odin, loki, hemidalla

  • took in alpha proteobacterium via membrane protrusions to enslave the bacterium (future mitochondrion)
• prometheoarchaeum- hiroyuki imachi 2020
• LUCA

  • last universal common ancestor; 1st eukaryote
• 2 types of multicellularity

  Aggregative multicellularity- dictyostelium sorocarp

  cohesive multicellularity- cells stick together after division: plants, fungi, animals
• predation as an origin for multicellularity- alga chlamydomonas and its predator paramecium
• multicellularity- adhesion, communication, cooperation, specialization (differentiation)
• GK-PID discovery

  • 2015 eLife paper
  • guanylate kinase
  • prtn interaction domain (PID)
• Gene Duplication

  • single mutation repurposed the prtn and instead of its enzymatic activity, it became capable of binding other prtn
  • and then differentiation/acquisition of new function
• orientation of mitotic spindle: by incorporating the Gk-PID w/ AA residue mutation predicted for binding (from enzyme to scaffolding)
• choanoflagellates: metazoans closest unicellular cousins; both have colonial forms (for feeding)
• opisthokonda- animals and fungi and unicellular gp (choanoflagellates

  amoebozoa- free living and parasitic amoebae and CSM
• plantae- primary endosymb. and possess plastids;

  • land plants and green algae; red algae; glycophytes

  chromalveolata- secondary endosymb. already containing primary plastid; unicellular algal gps
• rhizaria: rRNA seq data; free living foraminifera (marine amoebae) and radiolaria and animal parasites

  excavata: unicellular heterotrophic flagellates, including parasitic species that cause diseases; most contentious of major supergroups
• 2 domains

  • Adl and colleagues 2019
  • amorphea (w/o form/shapes)
  • diaphoretickes (diversity in features)
  • previously unikont and bikont
• amorphea

  • supergroups: CRuMs, amoebozoa, obazoa
  • opisthokonta is classified under obazoa
  • contains holozoa (including choanoflagellates and metazoa) and nucletmycea
• diaphoretickes

  • supergroups: archaeplastida, sar, crypista, haptista
  • SAR includes stramenopiles, alveolata, rhizaria
• supergroup changes

  • new minor supergroups: haptista, CRuMs, cryptista
  • supergroup excavata has been deleted due to "loss of monophyly in the Excavata" and becomes the informal "excavates" (adding quotation marks)
  • "excavates" contain 2 major groups- metamonada, discorba
• mangrove bacteria: complex cell
• giant microbe:

  • world's biggest plant
  • ancient and incredibly resilient seagrass
  • at least 4500 years old
  • polyploid
  • one plant has expended over 180km in shark bay; largest known plant on earth
  • poseidon's ribbon weed
• early multicellular eukaryotes

  • 1.63 billion year old multicellular eukaryotes from North China
  • cellularly preserved multicellular microfossils
  • microfossils consist of unbranched filaments with cell diameters up to 190 micrometers
  • spheroidal structures, possibly spores, occur w/in some cells
  • findings support the hypo that simple multicellularity arose early in eukaryotic history