Origin of Life and First Cells
Universe 14 byo
Solar system 4.5-5 byo
Earth - 4.5 byo
- atmosphere of early earth (Image) thought to contain:
carbon
monoxide
carbon
dioxide
nitrogen
water vapor
BUT NO
FREE OXYGEN and no ozone layer
- atmosphere of present day
78% nitrogen N2
21% oxygen O2
0.036% carbon dioxide CO2
traces of rarer
gases
- terrestrial synthesis
- Miller-Urey (Image)
- shallow seas - Primordial soup
- bubble
model (Fig
19.2)
- hydrothermal vents Hydrothermal
vents in action
- lightning Fig 19.1
- extraterrestrial - comets, asteroids, meteors (Panspermia)
Define prokaryotic,
eukaryotic, heterotrophic and autotrophic
The evolution of prokaryotes Early and modern prokaryotes (Image)
- earliest fossils are 3.5 billion years old = stromatolites
- Fossil (Image) & Modern
- evolved 3.6 bya - 4.0 bya
- 2.0-3.5 bya cyanobacteria (photosynthetic) oxygen revolution
Organisms divided into 3 domains. Image
characteristics of 3 domains.
Domain
Bacteria
Domain
Archaea
Archaea vs. Bacteria
Cell walls lack peptidoglycan which Bacteria cell walls have
Not inhibited by antibiotics
Archaea has more in common with Eukarya than with Bacteria
Archaea Diversity
Methanogens
Extremophiles
Thermoacidophiles Fig 19.8
Structural Characteristics- Lack membrane-bound organelles and nuclear
membrane. Table
19.1a and 19.1b
Size
Image
Three
shapes of prokaryotes (Image)
Gram-positive
vs. Gram-negative (Image) Fig 19.4
Structure
of flagella (Image) Pili
(Image) Fig 19.6
Special
membranes (Image)
Bacterial
conjugation and plasmids Fig 19.5
Diversity of prokaryotes (Image)
Types of metabolism (Image)
Autotrophs and heterotrophs
Saprobes
Parasites
Prokaryotes and the environment
Bacteria as Human Pathogens - a parasitic
relationship Table
19.2
Examples: cholera,
(water),
leprosy,
tetanus, anthrax,
Lyme
disease, bacterial pneumonia, whooping cough, syphilis, gonorrhea, bubonic
plague, (life cycle)
Can be used as
agents of bioterrorism
More than half of
our antibiotics come from soil bacteria. Antibiotics do not work on viruses,
but evolved as a method for some bacteria to be able to kill other bacteria -
an extreme form of competition.
The Viruses
Viruses and Disease Table 19.3
Prions and mad cow
disease Movie
Get more information on diseases at the CDC.