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iLabs: “Catch of the Day” – Paramecium: The Tarheel Protist!

August 16, 2014

Today’s blog post was created by our Investigate Lab staff and Kai, one of our wonderful volunteers!  Enter the underwater world of a special “Tarheel” – the Paramecium

by the Micro World Investigate Lab staff and volunteers:

Every state has a state bird, but North Carolina’s also got a wonderful candidate for state protist: Paramecium. It looks a bit like a foot with a tarheel, a great match for the Tar Heel State.

A Paramecium feeding on algae in the Micro World lab culture

A Paramecium feeding on algae in the Micro World lab culture

According to Rice University’s Experimental Biosciences Department, a paramecium is pretty large for a protist. It measures roughly half a micrometer in length, about one-sixteenth the length of an eyelash.

All paramecium are entirely covered in cilia, hairlike organs. They beat all at once to propel the paramecium forward, or wherever it wants to go.

Paramecium are well-known for hasty retreats. MicrobeWiki says that paramecium have been seen rotating up to 360 degrees to escape from predators.

Though it probably prefers flight over fight, a paramecium is definitely not defenseless. This protist has spinestrichocysts—lying right underneath its outer cell membrane. If a situation gets too dicey, it shoots them at predators to stave them off.

Another view of a Paramecium in culture

Another view of a Paramecium in culture

Paramecium, like humans, is a heterotroph, a hearty consumer of both plant and animal life.

Because a paramecium is clear, we can easily see what it’s eaten just by looking at it. This particular one seen above, seems to have been eating a lot of microscopic salad: it’s full of green plant matter from algae. That makes complete sense, given the paramecium’s living conditions. They’re lucky enough to be surrounded by their food 24/7. That’s the murky green stuff in the picture.

Paramecium have a mouth-like area called an oral groove running along the upper side of their bodies. It’s lined with fast-moving cilia that work like a conveyer belt to move food down into a paramecium’s body.

Instead of making use of a permanent stomach, a paramecium feeds via a process called phagocytosis. When it takes up food, the paramecium makes itself a temporary “stomach” out of its cell membrane. This vesicle encapsulates the food while the paramecium’s extremely small organs—organelles—pump in digestive enzymes to break down the food product.



Paramecium feeding by phagocytosis

Paramecium feeding by phagocytosis

The paramecium here are exploring, maybe even going out to dinner for some ubiquitous algae.

Sometimes, certain algae live in the body of a paramecium and provide food to it as a sort of “rent.”   That’s a symbiotic relationship, one where both involved species benefit from the arrangement. The bacteria that live in our digestive tracts are part of a symbiotic relationship that humans are part of. The gut bacteria get a place to live, and a share of the food we digest. We can’t digest our food without them, so we benefit, too.


4 Comments leave one →
  1. goldfire407 permalink
    August 16, 2014 3:01 pm

    Hi Deb, love this

    • August 29, 2014 1:09 pm

      Thanks so much! I appreciate your comments, and so do my staff members who write for the blog. 🙂

  2. August 18, 2014 5:02 pm


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