Astronomy Life In The Universe Ch 10

Front 1

What is life?

Back 1

things with the ability to evolve and adapt

Front 2

evolve

Back 2

meaning develop adaptations to their environment that improve their ability to continue

Front 3

What are the implications of life?

Back 3

life needs an energy source and need a means of reproduction

Front 4

what makes a good energy source?

Back 4

something easy to make, easy to store, capable of making things happen in a “typical” environment

Front 5

Name the 5 possible energy types

Back 5

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!!

Front 6

qualification for genetic codes

Back 6

lots of ability for variability within the code, ways of reading and writing the code, large complex chemical molecules

Front 7

chemical reactions through all mediums

Back 7

solids- chemical reactions slow
Gas- chemical reactions easily dispersed
liquids- chemical reactions proceed quickly

Front 8

solvent

Back 8

Chemical that can break apart solids into liquid phase, that can separate and mix apart many complex structures into the liquid phase

Front 9

normal life

Back 9

baseline for evaluating conditions for life to develop elsewhere

Front 10

the goldilocks syndrome

Back 10

the idea that earth is fit just for standard life

Front 11

extreme life

Back 11

forms of life show how far life deviates from “normal” and still survives and reproduces. Gives ideas on limitations of life on the universe

Front 12

Aquifex Aeolicus

Back 12

life at yellow stone hot springs (very hot!)

Front 13

Experience says that putting living creatures in boiling hot water kills them

Back 13

Denaturing of the proteins
High heat causes proteins to lose some of their structural/chemical properties
Breaks down the structure of the living cells

Front 14

Aquifex Aeolicus Properties

Back 14

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

Front 15

Aquifex Aeolicus Metabolism

Back 15

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)

Front 16

3 “Domains” of life on the basis of genetic linkage

Back 16

Archea
Bacteria
Eukaryota

Front 17

A. aeolicus

Back 17

one of the most “divergent” bacteria known

Front 18

Archaea

Back 18

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

Front 19

Archaea & Extremophiles

Back 19

Archaea are typically “primitive” organisms
Most single-celled “extremophiles” are members of archaea

Front 20

Chemosynthesis

Back 20

Energy generation NOT dependent on sunlight
Often (but NOT always) depend on other critters

Front 21

A. aeolicus survives by

Back 21

pure chemosynthesis (no photosynthesis; no eating other life forms)

Front 22

Types of chemosynthetic life:

Back 22

Methanogens (Methane)
Halophiles (Salt)
Sulfur reducers
Thermoacidophile (i.e. Aquifex aeolicus)

Front 23

Methanogens

Back 23

Things that use chemosynthesis to survive, and produce methane (CH4) as a by-product

Front 24

Well-known examples

Back 24

Swamp gas bubbles (methanogen byproduct)
Flatulence (bovine, human) – mmmm … Tijuana Flats!

Front 25

Methanogens typically only thrive

Back 25

in environments where other “chemically aggressive” elements (like O) are rare

Front 26

Methanogens have been found thriving

Back 26

as slime mats on deep rocks below Earth’s surface (endoliths)

Front 27

Halophiles

Back 27

Microbes that survive by chemosynthesis in VERY salty water (i.e. 5x to 10x that of ocean water

Front 28

Halophiles Locations

Back 28

Great Salt Lake (Utah)
Dead Sea (Israel/Jordan)
Owens Lake (California)
Evaporation estuaries in San Francisco Bay

Front 29

Black Smokers

Back 29

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

Front 30

Black Smoker Ecology

Back 30

Not just life – fully-developed ecosystems!
Crabs, shrimp, clams, Pompeii worms

Front 31

Pompeii Worms

Back 31

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!

Front 32

Pompeii Worms (second)

Back 32

“Hairy” back is heat-resistant microbe mat (symbiotic with worm mucus)
Red “feathers” include hemoglobin; separates hydrogen sulfide from vent flow

Front 33

What feeds the ecosystem?

Back 33

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 (!)