Week13 - 4/16/2010 Unusual or Extreme Habitats (Chapter 15)...

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4/16/2010 1 Quiz on the 22 nd of April Unusual or Extreme Habitats (Chapter 15) Adaptations to Extremes Saline Lakes Hot Springs Cold Habitats Ultra-Oligotrophic Habitats Deep Subsurface Habitats Neuston Molecular Adaptations to Extremes DNA- stabilized against high temperature by more binding proteins , more C-G bonds RNA- more extensive regions of base pairing in areas that need to hold conformation Membranes- higher temperatures increased saturation (higher percentage of single bonds), branching and length. In Archaea , higher proportion of ether lipids Proteins- thermal stability, more β sheets and α helix, hydrophobic core, high external charge ( i.e. more structural integrity ) Cold Avoid damage of ice crystals forming in cells Have built in antifreeze The antifreeze molecules allow icefish to live in subfreezing water by plugging gaps in existing small ice crystals and preventing the attachment of more ice molecules. Ice crystal growth is thus effectively stopped Molecular Adaptations to Extremes , continued http://www.nsf.gov/pubs/1996/nstc96rp/sb3.htm ht p:/ srufaculty.sru.edu/jack.layne/jrlres.htmht p:/ srufaculty.sru.edu/jack.layne/jrlres.htm http://www.youtube.com/watch?v=Fjr3A_kfspM Trematomus hansoni notothenioid fish ht p:/ www.biology-blog.com/blogs/permalinks/10-2008/survival-of-antarctic-antifreeze-fish.htm
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4/16/2010 2 Molecular Adaptations to Extremes , continued Saltwater: Need ways to stabilize proteins from too many ionic interactions. Complex animals pump out salt, halophilic bacteria and Archaea are isotonic with water. Some organisms use glycerol to remain isotonic Lack of water: similar to salt. Organisms in temporary habitats must be able to withstand desiccation Saline Lakes Closed basins : water leaves primarily by ___?____ Chemistry dependent upon watershed Limitation by O 2 may be important because solubility ____? ___ with increased salinity Brine shrimp ( Artemia sp.) can be important consumers, will not coexist with fish http://www.pashnit.com/pics/road5/Hwy120/MichaelMaloney_MonoLakeTufa.jpg ht p:/ farm4.static.flickr.com/3422/3231673944_e5f942390d_b.jpg Mono lake, CA Lake Assal, Djibouti Brine shrimp Artemia franciscana (ASLO image gallery) Commercial fishery for them in the Great Salt Lake, UT Hot Springs Thermophilic - heat loving organisms Bacteria and Archaea are the only organisms that inhabit highest temperatures Chemistry variable from very acidic to basic Acid springs dominated by sulfide; sulfur oxidizing bacteria common Basic springs dominated by carbonates or silicates http://www.calacademy.org/exhibits/xtremelife/images/grand_prismatic_spring.jpg
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4/16/2010 3 Upper Temperature Tolerances Fish 38 Vascular plants 45 Insects 50 Ostracods 50 Mosses 50 Protozoa 56 Algae (eukaryotic) 60 Fungi 62 Cyanobacteria 73 Photosynthetic bacteria 73 Group Approximate upper limit ( o C)
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This note was uploaded on 11/14/2010 for the course NRM 2305 taught by Professor Staff during the Spring '08 term at Texas Tech.

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Week13 - 4/16/2010 Unusual or Extreme Habitats (Chapter 15)...

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