BIOG 1106 - Unit 4 Slides / slide 24

 

Slide 24.	Light micrograph of Oscillatoria sp. (brown strands), a filamentous blue-green alga or cyanobacterium. The strands of alga are in fact linear colonies of primitive, single-celled, prokaryotic organisms, more closely related to bacteria than to algae. They are considered to be one of the most primitive organisms, dating back to pre-Cambrian times. The strands (known as trichomes) of Oscillatoria exhibit swaying motion & can also move backward & forward. The mechanism for this movement is not yet fully understood. Magnification: x200 at 35mm size. Credit: Andrew Syred / Photo Researchers, Inc.	Light micrograph of the filamentous blue-green algae Oscillatoria sp. A small ciliate protozoan is also visible as the small oval body towards lower left. Blue-green algae are considered to be among the most primitive organisms dating back to pre-Cambrian times. A single row of cells such as one of these strands is called a trichome. When surrounded by a gelatinous sheath it is called a filament. Oscillatoria lacks a slimy sheath. The strands of Oscillatoria exhibit a swaying motion & can also move backward & forward. The mechanism for this movement is not yet understood. Magnification: x40 at 35mm, x80 at 5x7cm size. Credit: S. Stammers / Photo Researchers, Inc.