What evidence supports the idea that a stentor is an heterotroph?

Answer 1

Autumn (the Fall) is a good time of year to find Stentor because leaves falling into a pond increase the bacteria population feeding on the decaying vegetation. This leads in turn to an increase in the population of protozoa such as Stentor which feed on the bacteria.

Colonies of Stentor often occur, in which the lower parts of the animals are covered with a mucilaginous substance which they secrete.

The rim of the trumpet is surrounded by a crown of cilia (vibrating hairs) which beat to produce a current that draws particles of food down into the gullet.To find new feeding grounds, the animal swims by means of cilia that cover the body.

Stentor can be very colourful - there are green, blue and amethyst colored species. The figure on the left shows a green form using dark field illumination. The green color is a result of the microscopic green algae which Stentor ingests. The algae live in symbiosis with the Stentor, ie the algae and Stentor mutually benefit from the close association. The algae uses photosynthesis to convert Stentor's waste products to useful nutrients.

Answer 2

Cilia surround the "mouth" end and sweep the surrounding water toward the entrance.

Stentor extends out into the water and waves the cilia ... especially when the pH is a little on the low side indicating that bacteria are in the area.