- outlines of bacterial evolution
- looked at Eubacteria (not archaeobac)
- Saw conserved INDELS: showed Gram + are most ancient (monoderm) - ancestral, and Gram - are more recent (diderm)
- Deinococci are intermediates
- Diagram shows:
- 1. thick cell membrane of 1 plasma membrane & pep-glycan cell wall
- 2. Thin cell wall w/2 plasma membranes & pep-glycan cell wall
- 3. Thick cell wall w/2 plasma membranes
Lonhiemne et al. 2010
- Endocytosis-like protein
- Argued opposite of Embly & Martin
- Said Endo-membranes (internal membranes) evolved 1st, BEFORE Endosymbiosis of mitochondria and chloroplasts.
- ie: nuclear membrane evolved prior to mitochondria
Embly, ™, Martin W. 2006
- Eukaryotic evolution changes & challenges
- Argued opposite of Lonheimne
- Said Proto-mitochondrian may have evolved 1st, BEFORE nuclear membranes
- This done by endosymbiosis
- Host: Archaeobacteriu
- Endosymbiont that evolved into pro-mitochondrian: Eubacterium
Bell, Philip 2004.
- Viral Eukaryogenesis Theory
- 1st to evolve is Eukaryotic nucleus w/linear chrom…may have evolved from dsDNA virus
- 3rd genome important: dsDNA virus, which infected host cell w/out lysing it immediately
- Host cell: archaeobacterial cell (provides the genes needed for REP, TRANSCRIPTION & TRANSLATION)
- Endosymbiont: Provides METABOLISM for 1. glycolysis, 2. Krebs, 3. oxidative phosphorylation
- Evolved from eubac symbiont, which becomes mitochondriont
- BEST job explaining features of euk vs. pro
Alvarez & Asaro 1990
- Extraterrestrial Impact
- Cretaceous/Tertiary extinction @ 65MYA caused by METEOR impact
- Use data from newly discovered crater: Chicxulub crater @ Yucatan Peninsula of Mexio
- Volcanic eruption
- K/T extinction @ 65MYA may have been caused by Deccan Traps volcanic activity in India
Sereno, P 1999.
- Evolution of Dinosaurs
- Dinosaurs experienced # of ADAPTIVE Radiations & REGIONAL extinctions B4 K/T extinction…but this killed off the last of the non-avian dinosaurs
- Regional extinction ie: Triassic/Jurassic
Alvarez & Muller, 1984.
- Evidence from crater ages form periodic impacts on Earth
- 1st to postulate periodicity of meteorite impacts
- Statistical evidence for a 28MY periodicity to meteor impacts during past 250MY!
Raup & Sepkoski, 1986.
- Periodic extinction of families & genera
- Est. timeline of 26 MY periodicity of major MARINE extinctions over past 250MY!
- Diversification and extinction in the history of life
- NO EVIDENCE of Periodicity to Mass extinctions in Marine or Terrestrial habitats over the past 600MY!
- Extinctions: bad genes or bad luck?
- Argued all extinctions may be due, at least in part, to meteorite impacts.
- Looked at Meteors in the FOSSIL record
Rohde & Muller 2005.
- Cycles in Fossil Diversity
- Statistical significant support for hypothesis that MARINE EXTINCTIONS follow a 62MY CYCLE!
- This occurs during Paleozoic, Mesozoic & Cenozoic Eras
- May be attributed to galactic movements of SOLAR system
Ward P. 2006
- Impacts from the Deep
- All major extinctions in the past may share common feature: global warming (although may be due to volcanic or meteor)
- Starts w/INCREASE in CO2 levels, which increase temps in atmosphere & oceans
- Leads to INCREASE in CH4 building from ocean floor (worse than CO2 for ozone layer)
- Leads to INCREASE in Hydrogen SULFIDE building from ocean floor (animals cannot tolerate this)
- leads to ANOXIA
- This Hydrogen SULFIDE increase caused the Permian/Triassic boundary (Paleozoic end and start of Mesozoic) around 251MYA…then there was a SLOW recovery period that followed
- Dinosaurs were best adapted to survive b/c have BEST respitory tracts
Gould & Lewontin, 1979.
- Spandrels of San Marco
- Non-selective forces: May be more important when explaining what appear to be Adaptation vs. selective forces
Linnen et al. 2009.
- On origin & spread of an adaptive allele in deer mice
- Agouti Mutation: 8000yrs ago occurred in deer mice living in Sand Hills of Nebraska. Have been preserved by Natural selection (mutation changes color from brown-->tan)
- On Origin of species - Sterility of Hybrids
- F1 Hybrid Sterility (intrinsic post-zygotic mechanism): NOT be of any SELECTIVE advantage of any of the organisms that possess it
Coyne & Orr. 2004
- Post-Zygotic Isolation
- F1 hybrid sterility & F1 hybrid inviability Could EVOLVE by SELECTIVE forces