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33 Cards in this Set

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  • Back
What is life?
things with the ability to evolve and adapt
evolve
meaning develop adaptations to their environment that improve their ability to continue
What are the implications of life?
life needs an energy source and need a means of reproduction
what makes a good energy source?
something easy to make, easy to store, capable of making things happen in a “typical” environment
Name the 5 possible energy types
Nuclear energy? (Requires 10,000,000K and high pressure)
Solar energy? (Hard to store light)
Thermal energy? (tends to “leak” out; hard to store)
Kinetic energy? (hard to store)
Chemical energy? Works!!
qualification for genetic codes
lots of ability for variability within the code, ways of reading and writing the code, large complex chemical molecules
chemical reactions through all mediums
solids- chemical reactions slow
Gas- chemical reactions easily dispersed
liquids- chemical reactions proceed quickly
solvent
Chemical that can break apart solids into liquid phase, that can separate and mix apart many complex structures into the liquid phase
normal life
baseline for evaluating conditions for life to develop elsewhere
the goldilocks syndrome
the idea that earth is fit just for standard life
extreme life
forms of life show how far life deviates from “normal” and still survives and reproduces. Gives ideas on limitations of life on the universe
Aquifex Aeolicus
life at yellow stone hot springs (very hot!)
Experience says that putting living creatures in boiling hot water kills them
Denaturing of the proteins
High heat causes proteins to lose some of their structural/chemical properties
Breaks down the structure of the living cells
Aquifex Aeolicus Properties
These are very small bacteria
Prokaryotes
Genome structure is only 1/3 as long (complex) as E. coli (a model “simple” bacteria)
Single DNA molecule in a circular chromosome
Aquifex Aeolicus Metabolism
A. aeolicus survives from H, O, CO2, and mineral salts
Requires oxygen for respiration (so, not that primitive)
But … no need for sunlight, nor sunlight-using food !!
Purely chemical food source (in the presence of thermal energy from the water)
3 “Domains” of life on the basis of genetic linkage
Archea
Bacteria
Eukaryota
A. aeolicus
one of the most “divergent” bacteria known
Archaea
Very small critters (~1 micron in length)
No nucleus (like bacteria)
Different tRNA from bacteria and Eukaryotes (which have same tRNA as each other)
Cell structure LOOKS like other cells, but made from different chemicals
All bacteria/eukaryotes us D-glycerol isomers; Archaea only use L-glycerol
Archaea & Extremophiles
Archaea are typically “primitive” organisms
Most single-celled “extremophiles” are members of archaea
Chemosynthesis
Energy generation NOT dependent on sunlight
Often (but NOT always) depend on other critters
A. aeolicus survives by
pure chemosynthesis (no photosynthesis; no eating other life forms)
Types of chemosynthetic life:
Methanogens (Methane)
Halophiles (Salt)
Sulfur reducers
Thermoacidophile (i.e. Aquifex aeolicus)
Methanogens
Things that use chemosynthesis to survive, and produce methane (CH4) as a by-product
Well-known examples
Swamp gas bubbles (methanogen byproduct)
Flatulence (bovine, human) – mmmm … Tijuana Flats!
Methanogens typically only thrive
in environments where other “chemically aggressive” elements (like O) are rare
Methanogens have been found thriving
as slime mats on deep rocks below Earth’s surface (endoliths)
Halophiles
Microbes that survive by chemosynthesis in VERY salty water (i.e. 5x to 10x that of ocean water
Halophiles Locations
Great Salt Lake (Utah)
Dead Sea (Israel/Jordan)
Owens Lake (California)
Evaporation estuaries in San Francisco Bay
Black Smokers
Black smoker vents
Found in deepest parts of the ocean
Volcanic, mineral-enriched water outflows
Rich in iron, sulfur compounds
Very little/no oxygen
Discovered in the 1970s
Temps as high as 750 F (!!)
Does not boil, though, due to extreme pressure at this depth
Black Smoker Ecology
Not just life – fully-developed ecosystems!
Crabs, shrimp, clams, Pompeii worms
Pompeii Worms
Tube worms anchored near black smoker vents
Bottom end has very high temps; top end more like 70F
Hot water flows through tubes; length as much as 10 feet!
Pompeii Worms (second)
“Hairy” back is heat-resistant microbe mat (symbiotic with worm mucus)
Red “feathers” include hemoglobin; separates hydrogen sulfide from vent flow
What feeds the ecosystem?
Sulfur-reducing extremophile archaea!
Metabolism centers on hydrogen sulfide (not oxygen, nor CO2!)
Pompeii worms (and some clams) seem to have symbiotic relationship with microbes
Worm “feathers” gather H2S and bring it into tube, where billions of microbes live
Microbes “digest” minerals with sulfur metabolism, releasing CO2 byproduct
Worm uses CO2 to digest minerals as well
Other life forms live on microbes, worms, etc.
Worms may live as long as 200+ years (!)