About microscopic forms of life, including Bacteria, Archea, protozoans, algae and fungi. Topics relating to viruses, viroids and prions also belong here.
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I'm having trouble finding out about how protozoans (specifically the euglena, paramecium and ameba) sense their environment. Does this mean they can't? I know the euglena has an eye spot for detecting light, but what about the others?
Please let me know, even an informative website will help.
Actually, I'm interested in the same thing and I've come across very little on single celled animal sense. I would offer this, though:
The paramecium (which I've been observing for a few weeks now), do have some senses. They have a sense of touch and a sense of taste. This is clear from their behavior. They may also be sensitive to light, but I haven't noticed that really.
Now, they clearly don't have the senses in the same manner that we do. They're only one cell, so they don't have a nervous system of any kind, so these senses must clearly be chemical in nature and their responses are simply reflexes to stimuli that have been adapted through evolution.
But most of this is pretty much simply through observation and drawing my own conclusions. As I said, I've come across very little information on the topic.
This maybe of some help to you.
Protozoa are animals that no two people can agree on, or so it seems. Most protozoans, not all, are somewhat phototropic and galvanotropic. The presence of a photosensitive spot is not always necessary in detecting light. Stentors and Paramecia are good examples. As for them being aware of their surroundings, most of them seem to respond to various stimuli by trial and error behavior, at least to my observations. Also in my observations they seem to be opportunistic in their feeding habits and the amoeba can be quite selective in what it will ingest as food. You also may try searching "Kingdom Protista." This site will give you a basic rundown of the kingdom and breifly discuss some of the lighter subject data on them. There is tons of information on protozoa on the interenet and on individual species. A good way to start is to begin searching such things as "free-living protozoa, free-living amoeba, ciliophora, sarcodina, and mastigophora"
Ken Ramos, Aviation Ordnanceman USN Ret.
Western North Carolina
"If you see an explosives handler running...try to keep up with him!"
Ken's Nature Study
Paramecium uses its cilia to some extent for detecting objects by touch. Current thinking is that when the ciliate touches something, a transmembrane electrochemical event occurs that is somehow tranferred through at least some of the cytoskeleton, and thereby causing such phenomena as the avoiding reaction....monovalent and divalent cation flux across the membrane is involved too. The eyespot of euglenoid flagellates transduces light energy into changes in the bending of the flagellum (at its base) and this bending is transmitted along the rest of the flagellum. Amoebae seem to sense their environment via surface glycoprotein receptors (they can for example determine what they are engulfing in this way)...hope this is helpful.
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