Background
The relationship between 2 organisms can have varying degrees of association. In a commensal relationship, one organism is unharmed and the other benefits, e.g., the mealworm and gregarines. In a symbiotic relationship, 2 organisms form a partnership that can be (but isn’t always) beneficial to both. There are degrees of symbiosis, which range from a temporary association to one that persists from generation to generation, e.g., termites and their digestive tract protozoa.
Symbionts are sometimes so mutually dependent that they cannot exist separately, but more often there is a lack of cooperation between 2 organisms, resulting in parasitism. In parasitism, the parasite benefits at the expense of the host. Examples of this include 2 parasites that infect humans, causing serious diseases. The first, Plasmodium falciparum, causes malaria; and the second, Trypanosoma brucei, causes African sleeping sickness.
Symbionts are sometimes so mutually dependent that they cannot exist separately, but more often there is a lack of cooperation between 2 organisms, resulting in parasitism. In parasitism, the parasite benefits at the expense of the host. Examples of this include 2 parasites that infect humans, causing serious diseases. The first, Plasmodium falciparum, causes malaria; and the second, Trypanosoma brucei, causes African sleeping sickness.
Trichonympha
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Pyrsonympha feeding in termite gut.
A bit more about flagella...and an introduction to the diversity of various phyla.
A flagellate is an organism with one or more whip-like organelles called flagella. Some cells in animalsmay be flagellate, for instance the spermatozoa of most phyla. Flowering plants do not produce flagellate cells, but ferns, mosses, green algae, some gymnosperms and other closely related plants do. Likewise, most fungi do not produce cells with flagellae, but the primitive fungal chytrids do. Many protists take the form of single-celled flagellates.
The word flagellate describes a particular construction of eukaryotic organism and its means of motion. The term does not imply any specific relationship or classification of the organisms that possess flagellae. However, the term "flagellate" is included in other terms (such as "dinoflagellate" and "zooflagellate") which often are more formally characterized.
A flagellate is an organism with one or more whip-like organelles called flagella. Some cells in animalsmay be flagellate, for instance the spermatozoa of most phyla. Flowering plants do not produce flagellate cells, but ferns, mosses, green algae, some gymnosperms and other closely related plants do. Likewise, most fungi do not produce cells with flagellae, but the primitive fungal chytrids do. Many protists take the form of single-celled flagellates.
The word flagellate describes a particular construction of eukaryotic organism and its means of motion. The term does not imply any specific relationship or classification of the organisms that possess flagellae. However, the term "flagellate" is included in other terms (such as "dinoflagellate" and "zooflagellate") which often are more formally characterized.
Procedure
We will study the digestive tract protozoa of termites using Termite Digestive Symbionts and some basic equipment. We will especially focus on the relationship between diet and symbiosis and examine the protozoans, such as the flagellate Trichonympha, found in the digestive tracts of termites. Here’s how.
- Place a termite on a microscope slide.
- Use dissecting needles to separate the tip of the abdomen from the rest of the body. Be careful not to damage the gut.
- Place the hindgut (enlarged section) in a drop of 0.5% saline solution and tease it apart. Wash the protozoa free of the mucosa with a little more saline.
- Discard the gut, cover the protozoa with a cover glass, and examine them under a compound microscope.
Assignment
Prepare a labelled drawing at at least two different magnifications (separate drawing for each student).
At some point during the class period, complete a microscope operation check out (with teacher).
At some point during the class period, complete a microscope operation check out (with teacher).
