Paramecium is a simple, single celled organism, but even that can respond to its environment.
From the victoriaellis.scienceblog.com
But when the paramecium moved, signals in the zebrafish brain tracked the movement across the visuotopic map.
From the newscientist.com
If you compressed the Universe into a disk, it would be about 200 microns thick, or about the size of a paramecium.
From the scienceblogs.com
Paramecium aurelia, the best known of all ciliates.
From the en.wikipedia.org
Readers may be familiar with motile cilia, which can be found on a paramecium or in our trachea or reproductive organs.
From the sciencedaily.com
Phagocytosis has been maintained during evolution and was shown to have important functions in organisms such as amoeba and paramecium.
From the nature.com
Kubrick's work on screen tends to be the eye of a scientist examining humanity as if it were a paramecium under a microscope.
From the en.wikipedia.org
There was no response when the paramecium was motionless, but when it started swimming, signals in the zebrafish brain matched the movement of its prey.
From the newscientist.com
So the fish's tiny brain needs to recognize and track a swimming paramecium against a visual background that is rich in distracting patterns.
From the sfgate.com
More examples
Any member of the genus Paramecium
Paramecium (parr-u0259-MEE-sh(ee-)u0259m, /u02CCpu00E6ru0259u02C8miu02D0u0283u2071u0259m/ or parr-u0259-MEE-see-u0259m, /u02CCpu00E6ru0259u02C8miu02D0siu0259m/) is a genus of unicellular ciliated protozoan, commonly studied as a representative of the ciliate group. Paramecia are widespread in freshwater, brackish, and marine environments and are often very abundant in stagnant basins and ponds...
Protist commonly found in pond water; slipper-shaped with coordinated parallel lines of rowing cilia
Contains a reservoir of membrane-forming material in discoid vesicles for the purpose of producing food vacuoles. The food vacuoles form at the cytopharynx when the cytopharyngeal membrane and the discoid vesicles fuse. ...
A free living unicellular animal, a protozoan. The surface of paramecium is covered in cilia, that beat in wave patterns to power swimming. (section 7.2)
Is larger than the ameba. It can be found in ponds with scum on them. It has more of a shape than an ameba, looking like the bottom of a shoe. It is covered with tiny hairs that help it move. These hairs are called cilia. The paramecium is able to move in all directions with its cilia.
A ciliated protist that lives in fresh water and eats other tiny organisms for food.