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Life in Extreme Environments.docx

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Department
Life Sciences
Course
LIFESCI 2H03
Professor
Luc Bernier
Semester
Winter

Description
Jan 14, 2013 2HO3: Life in Extreme Environments Temperature: 0°C - 50°C pH: 4 – 8 (these are the extreme boundaries) Pressure: 101.3 kPa O2, H2O, & CO2 Most organisms have a well-defined range of tolerance: - The optimum range of tolerance leads to the largest population o Outside of this the number of animals/species found declines - This model however doesn't take into account the biodiversity that is seen on earth People, plants and fungi are more similar them some bacteria that look almost identical under a microscope (this is according to the chart) Australian desert: - 12 months of drought - Frog species are still able to do very well in this environment Chile desert: - Less then 1mm of rain falls annually - Insects are still able to live here Antarctic Ocean: - The water is -2°C (the only reason that it is liquid is due to the large salt content which prevents it from freezing) - Fish are still able to survive in these conditions What is an Extreme Environment? - Liquid water (absolute requirement for life on earth) - Life requires energy - Redox chemistry: used to control energy flow o We are near the top of the redox chart * Extremophiles are organisms that are able to thrive in physically extreme environments * Extremophiles are able to exist in all of the chemical environments: 1) Physical - Temperature - Radiation - Pressure - Drought Jan 14, 2013 * most extremophiles need to adjust to several of these extreme environments, they are called polyextremophiles * 2) Geochemical - Salinity - pH Types of Extremophiles: Acidophiles: organisms that grow in acidic pH levels (low) Alkalophiles: organisms that grow in basic pH levels (high) Anerobes: organisms that live in conditions with no O2 Halophile: high salt concentration is required for growth Endolith: living inside rocks and minerals Methanogens: produce methane, from the reaction of H2 and CO2 Barophile: thrive at high pressures (700 X the normal pressure) Psychophiles: thrive in very cold conditions (under 15°C) (Hyper)thermophiles: extremely high temperatures (over 80°C) Xerophile: low water conditions * Picture of the ice core shows that a layer of algae, which can grow in the ice * Temperature: - At low temperatures ice crystals form these deform the structural components of cells - At high temperatures the biomolecules become denatured, no CO2 and O2 to diffuse - Most hyperthermophilic organisms are from the archaea kingdom o Pyrolobus fomarii capable of growing at 113°C  Found in hydrothermal vents  Resistant up to temperatures of 142°C (enzymes still active at this temp.) Radiation: - Energy is transit - Extreme levels of rad
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