Diatoms - PowerPoint PPT Presentation

by cheyenne cheung n.
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Diatoms

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  1. By: Cheyenne Cheung Diatoms

  2. Diatoms and Photosynthesis • Photosynthetic micro-organisms—autotrophic • Contain chlorophyll that are yellowish in color • An important source of food for marine organisms because they are photosynthetic Chloroplasts

  3. Structure of Diatoms • Single-celled with intricate skeletons • Bilateral symmetry, radial symmetry or asymmetrical • Shells made of silica with a layer of organic material • Skeleton called ‘frustule’

  4. Some are motile • Along the raphe (slit alongside cell) there are tiny microfibrils that help diatoms move • Can be found in long chains or colonies • Have both freshwater and marine habitats Chain Colony

  5. Symmetry • Centrate diatoms generally have radial symmetry • Pennate diatoms typically have bilateral symmetry • Both found in either fresh or salt water Radial symmetry Bilateral symmetry

  6. Did You Know? • Diatoms are responsible for 20-25% of all organic carbon fixation on the planet • Fossilized rocks composed of diatoms, known as diatomaceous earth, are commercially mined as abrasives or filtering aids • Diatoms are a major component of plankton • Many toothpastes contain diatom skeletons

  7. Video • http://www.youtube.com/watch?v=BH6l2Maq2eI&feature=related • http://www.youtube.com/watch?v=JYB5529hDPI&feature=related

  8. Review • What are diatom shells composed of? • How do diatoms get their food? • What kinds of symmetry do diatoms have? • What is the skeleton called? • Are diatoms motile? • What percentage of organic CO2 fixation are diatoms responsible for? Answers: 1. silica 2. photosynthesis 3. bilateral, radial, asymmetrical 4. frustule 5. yes 6. 20-25%

  9. Bibliography Pictures • http://www.ucmp.berkeley.edu/chromista/diatoms/diatomdiverse.jpg • http://i.treehugger.com/images/2007/10/24/diatoms-jj-001.jpg • http://botit.botany.wisc.edu/images/130/Protista_I/Diatom_Images/Grouped_diatoms_MC_.jpg • http://www.ucmp.berkeley.edu/chromista/diatoms/diatomsy.html • http://www.bgsu.edu/departments/biology/facilities/algae/html/P_and_G_ESF.html Information • http://www.mbari.org/staff/conn/botany/diatoms/jennifer/introa.htm • http://www.ucmp.berkeley.edu/chromista/diatoms/diatomsy.html • http://www.ucmp.berkeley.edu/chromista/bacillariophyta.html • http://www.microscopy-uk.org.uk/mag/indexmag.html?http://www.microscopy-uk.org.uk/mag/wimsmall/diadr.html