hloroexus aurantiacus “Color-changer, green to orange” einococcus radiodurans yrococcus furiosus Domain: Bacteria “Terrible berry, survives radiation” “Raging reball” Habitat: Hot springs around the world, including Domain: Bacteria Domain: Archaea Yellowstone National Park. Habitat: Widespread, including deserts, hot springs, Habitat: Hydrothermal vents in ocean oor; rst Energy Source: Mixotroph (phototroph and high mountains, polar regions and animal gut. discovered near volcanic islands in Italy. chemotroph). Mainly uses light energy from the sun. In the dark, can use chemical energy from inorganic Energy Source: Chemotroph. Uses chemical energy Energy Source: Chemotroph. Uses chemical energy compounds (sulphur and hydrogen). from organic compounds. from organic compounds. Challenges to Life: Heat, UV exposure, changing Challenges to Life: Dehydration, cold, acidic pH, Challenges to Life: Heat, pressure, changes in levels of light and oxygen radiation, oxidative damage oxygen levels when vent uids contact sea water

Adaptation: Can rebuild its genome, after radiation Adaptation: A protein called reverse gyrase helps breaks it into hundreds of fragments, using a unique maintain DNA structure in extreme heat. High Adaptation: Can do both photosynthesis (like DNA-repair mechanism. Produces antioxidants that temperatures tend to unzip double-stranded DNA. plants) and respiration (like animals), allowing it to protect proteins from radiation damage. Reverse gyrase twists DNA so much it can’t unravel. survive a range of light and oxygen levels. It is green during photosynthesis and orange during respiration. Talent: Radioresistant. Survives short doses of Talent: Hyperthermophile. rives in extremely hot radiation up to 5,000 Gy. Grows under constant temperatures. Grows best at 100°C (212°F), Talent: ermophile. rives in temperature range radiation levels of 50 Gy per hour. By comparison, a reproducing once every 37 minutes. of 35–70°C (95–158°F). Among the rst organisms dose of 5 Gy kills humans. on early Earth to do photosynthesis. Application: Helping researchers genetically Application: Research may lead to more ecient engineer plants that can grow in hot climates. Application: Studying this organism helps research- clean-up of nuclear waste, as well as new vaccines Adding a gene to another plant made it able to grow ers learn about the evolution of photosynthesis. and cancer treatments. in much higher temperatures. alobacterium salinarum sychrobacter arcticus “Breathing bug that disregards salt” “Cold bug from the poles” icrophilus torridus “Burning paint” Domain: Archaea Domain: Bacteria Domain: Archaea Habitat: Salty lakes around the world, including Habitat: Very cold places, including permanently fro- Great Salt Lake, Utah. zen soil and pockets of salt water trapped in sea ice. Habitat: Acidic environments, including hot springs and volcanic steam vents Energy Source: Chemotroph. Uses chemical energy Energy Source: Chemotroph. Uses chemical energy from organic compounds. from organic compounds Energy Source: Chemotroph. Uses chemical energy from organic compounds. Challenges to Life: Lack of water, temperature Challenges to Life: Cold, darkness, high salt, extremes, high salt, radiation, toxic chemicals starvation, dehydration, limited space. Challenges to Life: Acidic pH, high temperature.

Adaptations: Acid-resistant cell membrane acts as a Adaptation: Special pumps in the the cell balance Adaptation: Special enzymes modify lipids to keep barrier to protons, keeping the inside of the cell at a salt concentrations. e pumps keep salt levels inside the cell membrane exible in cold temperatures. more neutral pH of 4.6. Uses dierence in proton the cell equal to salt levels outside the cell, Also, since cold temperatures slow down chemical concentration between inside and outside the cell to preventing water loss and dehydration. reactions, proteins in the cell tend to be exible and generate energy. Smallest genome of any known more active. organism minimizes the work of DNA repair. Talent: Halophile. Can grow in extremely salty water, 10 times saltier than the ocean. Talent: Psychrophile. Can grow at extremely cold Talent: Acidophile. Grows best at pH 0. Most life temperatures, as low as -10°C (14°F). lives between pH 5 and 8; water has a pH of 7. Application: Researchers study halophiles to learn more about the important role they play in salt lake Application: Researchers study cold-tolerant Application: Acid-resistant enzymes could clean up ecosystems, which support millions of migrating bacteria to learn whether life might exist on icy toxic mine sites, or be used as food supplements since birds. worlds like Mars and the moons of Jupiter. the enzymes remain active in stomach acid. ellungiella salsuginea “Saltwater cress” ardigrade “Little water bear” (1,150+ species) Domain: Eukaryote (Plant – Angiosperm) ntarctic ce ishes Domain: Eukaryote (Animal) Habitat: Salty environments, including salt ats in (25+ species) northern Canada and seashores of eastern China. Domain: Eukaryote (Animal – Chordate) Habitat: Wet environments, including hot springs, deep-ocean sediments, glaciers, fresh-water lakes, Energy Source: Phototroph. Uses light energy from Habitat: Southern Ocean surrounding Antarctica. tropical forests, even the moss in your own backyard. the sun. Energy Source: Chemotroph. Eats krill, small Energy Source: Chemotroph. Eats plants and bacteria. Challenges to Life: High salt, cold temperatures, crustaceans and other sh. nutrient-poor soils, drought, ooding, toxic metals, Challenges to Life: Dehydration, extremely hot and short growing season Challenge to Life: Cold temperature cold temperatures

Adaptation: Roots have specialized ion transporters Adaptations: In a hibernation-like state called that keep out salt (sodium and chloride) but let in cryptobiosis, cells lose almost all water and stop all other nutrients (potassium). Vacuoles hold sodium Adaptation: Antifreeze proteins keep their blood metabolism. A sugar molecule, trehalose, protects away from the cytoplasm to prevent cell damage. from freezing. ey lack red blood cells, thinning membranes and proteins from breaking. their blood so that it ows better at low tempera- Talent: Halophile and psychrophile. Can grow and tures. ey absorb oxygen through scaleless skin. Talent: Can survive more extremes (temperature, reproduce in extremely salty soil and sub-zero pressure, radiation, dehydration) than any other temperatures. Talent: Psychrophile. Can thrive in very cold water, organism. ey can even survive outer space. 1.5 to -1.8 °C (28 to 35°F). Application: Research is helping scientists engineer Application: Research is helping us learn how crop plants that can grow in harsh climates and soil Application: Antifreeze proteins are used to prevent organisms can survive without water. Understanding conditions. A gene from this organism made cotton ice crystal formation in popsicles and ice-cream, as death-like cryptobiosis could allow us to reversibly and corn plants more tolerant to salt and drought. well as to preserve human tissue for transplantation. stop our metabolism for long-distance space travel. iftia pachyptila cidithiobacillus thiooxidans “Giant tube worm” “Sulfur-breathing, acid-loving rod” upriavidus metallidurans “Metal enduring” Domain: Eukaryote (Animal – Annelid) Domain: Bacteria Domain: Bacteria Habitat: e deep sea, near geyser-like vents on the Habitat: Sul de-rich, underground cave systems in ocean oor, miles below the surface. Mexico, Italy and elsewhere. Habitat: Soils rich in natural metals or metal waste from mines and processing plants. Energy Source: Chemotroph. Uses chemical energy Energy Source: Chemotroph. Uses chemical energy from organic compounds. found in inorganic compounds (hydrogen sul de). Energy Source: Chemotroph. Uses chemical energy from inorganic compounds. Challenges to Life: Extreme pressure, darkness, low Challenges to Life: Extreme pH, darkness, limited nutrients, toxic chemicals and extreme temperatures food resources, low oxygen, toxic gases Challenges to Life: Toxic chemicals (vent water can be over 300°C / 572°F)

Adaptation: Builds a “snottite” to concentrate its Adaptation: Metal-binding proteins convert metal acidic waste products. Snottites are too acidic for dissolved in liquid into solid metal. Solid metal is Adaptations: rough symbiosis with bacteria, most other organisms, reducing competition for pushed out of the cell through channels in the cell converts vent chemicals into food. How this and nutrients. Ion pumps raise the pH inside the cell, membrane, called heavy metal exporters. other organisms survive crushing water pressure is making it less acidic than its surroundings. unknown. High pressure changes the activity of some Talent: Metallophile. rives in places contaminated genes, but the functions of these genes are unknown. Talent: Acidophile. Grows best at pH 0–1. Most life with toxic heavy metals. lives between pH 5 and 8; water has a pH of 7. Talent: Piezophile. rives in high pressure miles Application: Researchers hope to use the microbe's below the sea surface. Application: Researchers study snottites to learn genes as biosensors, tools that would help industries more about early Earth environments, cave more easily locate gold for mining. is organism Application: Enzymes from this organism could be formation or expansion, and the possibility of life on may also be useful in cleaning up areas contaminated useful in industry because they function at high other planets—underground. with heavy metals. temperature and high pressure.