Download 09. Paramecium Species Reading B

Paramecium bursaria
Paramecium bursaria is a species of ciliate
protozoan that has a mutualistic symbiotic relationship with green alga called
Zoochlorella.
Habitat:
Paramecia are widespread in freshwater environments, and are especially
common in scums.
Predators:
In the 1930's a Russian biologist named Gause used Paramecium and Didinium to
examine the predator-prey relationship. Both are microscopic organisms.
Paramecium is the prey and Didinium is the predator.
Prey:
Paramecium feed on micro-organisms like bacteria, algae, and yeasts. To gather
its food, the paramecium uses its cilia to sweep the food along with some water
into the cell mouth after it falls into the oral groove. The food goes through the
cell mouth into the gullet, which is like the stomach. When there is enough food
in it so that it has reached a certain size it breaks away and forms a food
vacuole. The food vacuole travels through the cell, through the back end first. As
it moves along enzymes from the cytoplasm enter the vacuole and digest it. The
digested food then goes into the cytoplasm and the vacuole gets smaller and
smaller. When the vacuole reaches the anal pore the remaining undigested waste
is removed.
Anatomy:
P. bursaria is 80-150 µm long, with a wide oral groove, two contractile vacuoles,
and a single micronucleus as well as a single macronucleus.
Historical information:
The first eukaryotic kingdom was the kingdom Protista. 1 billion year ago, the
diverse protists appeared.
Interesting information:
The algae live inside the Paramecium in its cytoplasm and provide it with food,
while the Paramecium provides the alga with movement and protection.
P. bursaria is the only species of Paramecium that forms symbiotic relationships
with algae, and are often used in biology classrooms as examples of protozoans,
and as examples of symbiosis.