| Slide
20. | Light micrograph of Gloeocapsa sp.,
a type of blue-green algae or cyanobacteria. They reproduce
solely by fission, a form of asexual division in which two identical
algae are produced. LM 250x at
35mm Credit: Michael Abbey / Photo Researchers, Inc.
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Cyanobacteria. Colored Transmission electron micrograph
of a single cell of a cyanobacterium also called blue-green alga Pseudanabaena sp.
Blue-green algae maybe
the first oxygen-producing organisms to evolve,
thereby being responsible for the Earth's atmosphere. They are
related to bacteria (prokaryotes) containing no membrane-bound nucleus;
instead
nuclear material is dispersed throughout the cell. Photosynthetic lamellae
(layered structures green) are the primitive chloroplasts. The red circles
at center are polyphosphate granules. Pseudanabaena occurs as motile filaments
of cells, called trichomes. Magnification: x24,000 at 6x6cm size.Credit:
Dr. Kari Lounatmaa / Photo Researchers, Inc. |
