Life on EarthLife on EarthWhat is it? Is it on other planets?

Definition of Life?Definition of Life?

• Something that maintains homeostasis, grows, and reproduces– Fire?– Crystals?

• Something that grows and adapts– Computer program?

• Something that has a metabolic process

• Something that has a genetic code

• Dependence on water?

• “Definitions are concerned only with language and concepts; they can't expand our understanding of the world. We can only define things we already understand.”

• -Carol Cleland

Requirements for Life?Requirements for Life?

• Sun

• Appropriate temperature

• Neutral pH levels

• One atmospheric pressure

• Water

• However is this just for humans???– What about on foreign lands?

Erwin ShrodingerErwin Shrodinger

• Physicist

• 1944 defined life as something that, “…avoids the decay into equilibrium.”

• Second Law of Thermodynamics=entropy always increases

• When you die, your body reaches entropy

• Living things avoid entropy by taking in nutrients

Benton ClarkBenton Clark

• Astrophysicist at the University of Colorado

• Also works for Lockheed Martin

• Life exhibits 102 qualities

• Three main qualities– Life reproduces, uses energy, and these

functions follow instructions in the organism– RNA & DNA

Benton Clark cont.Benton Clark cont.

• Crystals are not alive because they haven’t evolved

• Not all living organisms reproduce– Mules & honeybees– People

• Dependence on water?

Does All Life Need Water?Does All Life Need Water?

• Life on Earth evolved with water, therefore it is dependent on it

• On Earth, life has been able to adapt to harsh environments

• Sulfuric acid as a solvent on Venus

• Methane-ammonia mixtures on Jupiter

• Extromophiles

Extremophiles!!

Life on the edge!!

What are Extremophiles?What are Extremophiles?

• Microbes living where nothing else can

• How do they survive?– Extremozymes

• Why are they are interesting?• Extremes fascinate us

– Life on other planets

• Practical applications are interesting– Medicine– Food preservation– Sterilization

Extremophile HistoryExtremophile History

• Definition - Lover of extremes• History

– Suspected about 30 years ago– Known and studied for about 20 years

• Temperature extremes– boiling or freezing, 1000C to -10C (212F to

30F) • Chemical extremes

– vinegar or ammonia (<5 pH or >9 pH)– highly salty, up to ten times sea water

Types of ExtremophilesTypes of Extremophiles

• Thermophiles and Hyperthermophiles

• Psychrophiles

• Acidophiles

• Alkaliphiles

• Barophiles

• Endoliths

• Halophiles

Research ProjectResearch Project

• Choose a specific extremophile with two other partners.

• Research the specific conditions where they live– What makes them so extreme?– How do they survive their extreme

environment?– Give examples of ones we have found as well

as their specific location• Create a PowerPoint to share your research with

the class!– Make sure to include pictures in your

presentation!

Thermophiles & HyperthermophilesExtreme Temperatures

Thermophiles & HyperthermophilesExtreme Temperatures

• Thermophiles 40 - 70℃ (104 - 158℉)– Densely packed proteins prohibit internal

water

• Hyperthermophiles 60 - 113℃ (140 - 235℉)– Found in hot acidic spring in Yellowstone– Also found near “black smokers”– Stops growing below 200℉

Archaea Strain 121Archaea Strain 121

• Location: Yellowstone National Park

PsychrophilesPsychrophiles

• Organisms that grow best in low temperatures -10 - 20℃ (14 - 68℉)

• Thrive in Arctic and Antarctic Oceans• Lower than -18℃ (0 ℉)is lethal,

except for Panagrolaimus davidi

• Natural antifreeze

Panagrolaimus davidiPanagrolaimus davidi

• Location: Antarctic

• Length: 1mm

AcidophilesAcidophiles

• Life in sulfuric ponds• pH levels from 1 to 5• Ability to pump out hydrogen atoms keeps

internal pH at 6.5• Cyanidium caldarium, a red algae; and

Dunaliella acidophila, a green algae, can survive below pH 1

• Ferroplasma acidarmanus, a fungi, lives at pH 0 in Iron Mountain, California

CyanidiumCyanidium

• A red algae

• Location: Yellowstone National Park

Deinococcus radioduransDeinococcus radiodurans

• Most durable organism known to man

• Can withstand radiation of 1.5 million rads

AlkaliphilesAlkaliphiles

• Live in soda lakes (Kenya) and carbonate-rich soils

• pH levels from 9-11

• Maintain internal pH of 8 from pumping hydrogen ions across cell membranes into the cytoplasm

BarophilesBarophiles

• Thrive deep in the ocean or far underground

• Most live at pressures of 400-700 atmospheres, but die at 1 atmosphere

Bacillus InfernusBacillus Infernus

• Location: Gold Mine in Africa

EndolithsEndoliths

• Organisms that live inside of rock or the pores in the rock

• Others feed on organic compounds from the autrotrophs

• Black smokers

• Thrive above 110℃• 4 - 7 km below the surface• May exist on Mars

Acropora CythereaAcropora Cytherea

• Discovered under Johnston Atoll

HalophilesHalophiles

• Thrive in high saline environments 10 x more saline than sea water (30% salt content)

• Accumulate potassium and glycine-betaine to offset high salinity

• May survive for millions of years in fluid inclusions of salt deposits– Have been found on Mars

• Europa and Callisto may have underground saline oceans

Dunaliella salina Dunaliella salina

• Found in California’s pink salt lakes

Life Comic BookLife Comic Book

• Get out your ET Table.

• Use your table to figure out where certain extremophiles could live.

• Choose an extremophile and a planet/moon and create a comic about the discovery of life!!