Transcript Building Blocks of Life

Diversity of Life
Diversity of Life
Kingdom
Diversity of Life
Carl Woese
using ribosomal RNA sequence
Viruses




Not a living organism
Parasite uses other
organisms to replicate
Infect all organisms,
particularly bacteria
10 million/ml in ocean
http://oceanworld.tamu.edu/resources/oceanography-book/Images/BacteriophageCartoon.jpg
http://www.eoearth.org/image/Infected_cell.jpg
Prokaryotes
 Domain Archaea
 Domain Bacteria
 Structurally simple,
lack most
organelles
 Mostly microscopic
 Circular DNA
http://www.windows.ucar.edu/earth/Life/images/celltypes.gif
Eukaryotes
 1 Domain: Eukarya
 4 Kingdoms: Protista,
Plantae, Fungi, and
Animalia
 Structurally complex
 Have membrane-bound
organelles with
specialized jobs
 Mitochondria and
chloroplasts – organelles
that were once
symbiotic bacteria
http://www.windows.ucar.edu/earth/Life/images/celltypes.gif
Diversity of Life - Archaea




Simple, primitive
Old (3.8 billion years)
Recently discovered (1970s)
Look like bacteria, but chemically different
http://www.ucmp.berkeley.edu/archaea/archaeamm.html
Diversity of Life - Archaea



Have reputation as
“extremophiles”
Found almost everywhere
Very common in oceans
Diversity of Life - Archaea


Extreme high and low temperatures areas
(thermophiles)
Volcanic hot springs, hydrothermal vents
Archaea “Strain 121” –
survives up to 121°C,
reduces iron into
byproduct magnetite
http://www.nsf.gov/od/lpa/news/03/pr0384.htm
Diversity of Life - Archaea



Extreme salty regions (halophiles)
Hypersaline lakes
Salinity 300‰ or more
Haloquadratum walsbyi
http://www.espacial.org/images/jpg2/haloquadratum_walsbyi.jpg
Diversity of Life - Archaea



Extreme alkaline and acidic areas
Extreme pressure - deep trenches
Anoxic muds
Picrophilus torridus –
lives at 60°C and pH=0
NASA
Archaea in acid mine drainage
http://microbewiki.kenyon.edu/images/4/4f/Picrophilus_torridus.jpg
Diversity of Life - Archaea

Symbiotic associations
with other organisms:


Methanogens – live in
digestive guts of
plankton, sea
cucumbers
Others still being
discovered
green – archaeum (Cenarchaeum
symbiosium)
red – red sponge (Axinella mexicana)
cell nuclei
Diversity of Life - Bacteria


Simple, old
Variety of shapes and sizes
Diversity of Life - Bacteria


Found almost
everywhere
(including extreme
environments)
Found in huge
quantities in the
ocean
Diversity of Life - Bacteria



Important part of
nutrient recycling
Decomposition of
organic matter
(dead, wastes)
Food for other
organisms
Diversity of Life - Bacteria




Cyanobacteria
(“blue-green algae”)
Green, blue, and red
photosynthetic
pigments
First photosynthetic
organisms on earth
Stromatolites (3 bya
and today) –
calcareous (CaCO3)
http://web.eps.utk.edu/HistoricalGeo/historicalimages/Stromatolite.jpg
Diversity of Life - Bacteria

Symbiotic associations
with other organisms:

Chemosynthesis in tube
worms, mussels, clams
at hydrothermal vents
and cold seeps
Diversity of Life - Bacteria

Symbiotic associations
with other organisms:

Digestive gut bacteria
(shipworms, bone
worms)
http://www.phschool.com/science/science_news/articles/images/gutless_wonder.jpg
Diversity of Life - Bacteria

Symbiotic associations
with other organisms:


Bioluminescence in
squid, fish
Vibrio, Photobacterium
http://microbewiki.kenyon.edu/images/c/c9/Vibrio_fischeri_1145457864.jpg
http://beacon-center.org/wp-content/uploads/2012/03/lumflaskmod1.jpg
http://www.divernetxtra.com/biolog/pics/0900flash1.jpg
http://www.pbs.org/wgbh/nova/abyss/life/images/wudep50.jpeg
Diversity of Life –
Metabolism
 Organisms that can make
own food = autotrophs
(“self feeders”)
 Organisms that must eat
other organisms or organic
matter for food =
heterotrophs
Diversity of Life –
Metabolism

7 different types of pathways possible
 4 heterotrophic:
 Aerobic respiration
 Anaerobic respiration
 Nitrogen fixation
 Anaerobic ammonium oxidation
 3 autotrophic:
 Light-mediated ATP synthesis
 Photosynthesis
 Chemosynthesis
Diversity of Life –
Metabolism
 Aerobic respiration, uses oxygen (O2),
“burns” organic matter to get energy:
C6H12O6 + O2 → CO2 + H2O + energy
(sugar)
(ATP)


Prokaryotes and eukaryotes
Decomposition of organic matter
Diversity of Life –
Metabolism





Anaerobic respiration, uses NO3-, SO4-2,
or CO2 instead of O2
Nitrogen fixation
 Makes nitrogen gas (N2) usable to
organisms as ammonia
Anaerobic ammonium oxidation
All of these 3 require anoxic conditions
All of these 3 are in prokaryotes only
Diversity of Life –
Metabolism
 Light-mediated ATP synthesis prokaryotes only
 Photosynthesis
 Prokaryotes and
eukaryotes (only algae
and plants)
 Need chlorophyll and
other pigments
 Converts inorganic
carbon to organic
 Photoautotrophs
Diversity of Life –
Metabolism
Photosynthesis
CO2 + H2O + light → C6H12O6 + O2
energy (sugar)
Diversity of Life –
Metabolism

Chemosynthesis:
 Energy from chemicals (H2S), not light
 Critical for life at hot and cold seeps
 Prokaryotes only
 Chemoautotrophs
http://oregonstate.edu/dept/ncs/photos/grazers.jpg
Diversity of Life –
Metabolism
 Autotrophs must also
use respiration to get
ATP energy
Diversity of Life –
Metabolism


7 classes of metabolic reactions possible
in prokaryotes
Only 2 in eukaryotes (photosynthesis,
aerobic respiration)
http://www.addletters.com/Godzillatron-football-sign-generator.htm
Prokaryotes vs. Eukaryotes
Prokaryotes
Eukaryotes
Domains/
Kingdoms
Bacteria, Archaea
Animalia, Plantae,
Fungi, Protista
Cellular Complexity
Simple
Complex, organelles
DNA structure
Simple, circular
Chromosomes in a
nucleus
Cellular
Organization
All unicellular
Some unicellular,
many multicellular
Metabolic pathways
Variety, 7 possible
Only 2 – aerobic
respiration &
photosynthesis
Feeding strategy
Auto & heterotrophy Auto & heterotrophy