How Does Life Work? Symbiosis Crossing the Kingdoms Algae & Protozoa
Paramecium bursaria, a freshwater protozoan, typically harbors hundreds of sym- symbiotic algae is stable and mutually beneficial in natural environments. Some protozoans, such as Paramecium bursaria, have developed symbiotic relationships with eukaryotic algae, while the amoeba Paulinella chromatophora . Chlorella algae as distributed within a single Paramecium bursaria cell. tested the symbiotic relationship of the protozoa and algae across.Is Zooxanthellae Algae?
Organisms from these groups are the causative agents of human diseases such as malaria and African sleeping sickness. Owing to the prevalence of these human pathogens, and to the ecological importance of the free-living protozoan groups mentioned above, much is known about these groups.
- A far from perfect host
This article therefore concentrates on the biology of these comparatively well-characterized protozoans.
At the end of this article is a summary of the contemporary protistan classification scheme. The coordinated beating of cilia propels protozoans through water. Natural history Size range and diversity of structure Protozoans range in diameter from a few thousandths of a millimetre to several millimetres. Because the group contains many unrelated or loosely related organisms, enormous diversity in structure and form exists. Courtesy of the American Museum of Natural History, New York City Flagellated protozoans The flagellated protozoans range from a simple oval cell with one or more flagella to the structural sophistication of the collared flagellates choanoflagellates, supergroup Opisthokonta.
The collared flagellates lack photosynthetic pigments and are therefore colourless. They have a single flagellum surrounded by a delicate circular collar of fine pseudopodia microvilli on which they trap food particles. In some marine species the whole cell is enclosed in an elaborate, open latticelike basket formed from strands of silica. Although some dinoflagellates supergroup Chromalveolata still contain plant pigments and rely to a greater or lesser degree on photosynthesismany members have lost the ability to photosynthesize.
All dinoflagellates are surrounded by a cell wall armour with a complicated pattern and possess two flagella, one of which beats in a transverse plane around the equator of the cell while the other beats in a longitudinal plane. For example, a wasp is a strongly-defended model, which signals with its conspicuous black and yellow coloration that it is an unprofitable prey to predators such as birds which hunt by sight; many hoverflies are Batesian mimics of wasps, and any bird that avoids these hoverflies is a dupe.
Amensalism is an asymmetric interaction where one species is harmed or killed by the other, and one is unaffected by the other.
Symbiosis in protozoa
Competition is where a larger or stronger organism deprives a smaller or weaker one from a resource. Antagonism occurs when one organism is damaged or killed by another through a chemical secretion. An example of competition is a sapling growing under the shadow of a mature tree.
The mature tree can rob the sapling of necessary sunlight and, if the mature tree is very large, it can take up rainwater and deplete soil nutrients.
Throughout the process, the mature tree is unaffected by the sapling.
Indeed, if the sapling dies, the mature tree gains nutrients from the decaying sapling. Zoanthus sociatus is a polyp colony that gets half its food from zooxanthellae protozoans, much like warm water reef corals.
This Trachelomonas euglenid grows a clear shell for protection; its single flagellum emerges from a tube at one end. Its green plastids originated in an ancient symbiosis with cyanobacteria Euglenas live partly on photosynthesis from chloroplasts that originated in an ancient symbiosis with cyanobacteria. They are called mixotrophs mixed eaters.
Symbiosis in protozoa - Faculty of Science Repository
This ocean acoel flatworm lives partly on photosynthesis from its symbiosis partners zooxanthellae, also found in corals Image credit Chris Loban Nutrition and Defense: Protists and Bacteria The toxic dinoflagellate protozoan Ostreopsis lenticularis hosts a variety of bacterial symbionts.
These bacteria not only provide nutrients but also create the toxins that poison fish that eat the tiny dinoflagellates.
When they have a sudden upwelling of nutrients, their numbers surge to create dangerous "red tides. Anabena azollae, the cyanobacterium symbiont of the floating fern Azolla.