slime mold
(Photo : Pexels / Chris F )

While multicellular organisms contain multiple cells, single-celled, or unicellular organisms, just have one organism to make up their being.

Single Cell Organisms

As implied in their name, single cell organisms depend on just one cell for them to carry out all necessary functions. These organisms include yeast, bacteria, and protists.

The biggest single cell organisms may be classified as eukaryotes or prokaryotes. Eukaryotes have a membrane-bound nucleus that holds genetic material, while prokaryotes lack the said genetic material-containing nucleus.

ALSO READ: Single-Cell Slime Mold Can Remember Food Locations, Puzzling Scientists

World's Largest Single Cell Organisms

Despite only consisting of one cell, there are some single cell organisms that can stretch remarkably long or grow quite big in size.

Caulerpa Taxifolia

The world's largest single cell organism is the Caulerpa taxifolia, which comes in the form of seaweed. This unicellular organism can stretch up to 10 feet in length. It is known to be quite invasive and to negatively affect other species and even humans.

Despite being an aquatic organism, the Caulerpa taxifolia is capable of surviving outside of water for 10 days. It can thrive in different kinds of habitats, including rocky outcroppings, sandy bottoms, natural meadows, and mud.

This creature is remarkably hardy. It can also reproduce from small pieces of the entire organism.

Slime Molds

Slime molds are also considered massive single cell organisms. While this is not the official name of these unicellular organisms, there are up to 900 different slime mold species. The biggest ones are capable of spanning 3 feet.

Though these creatures begin as tiny creatures that are like amoeba, they can end up merging in particular conditions. For one, plasmodial slime molds can merge together to form a single cell with several nuclei.

Syringammina Fragilissima

Syringammina fragilissima is another single celled organism, that is an amoeba by nature, that can span up to 8 inches in diameter. Its single cell expands and forms several interconnecting and hollow-branched tubes, which secrete a form of organic cement that sand and sediment particles adhere to.

Acetabularia

This algae appears to have a mushroom shape, but it can grow to a height of four inches and live in huge clusters. This single cell organism, which is also referred to as Mermaids Wineglass, is also a multinucleate organism. This means that it has several nuclei within its cell.

This unicellular organism is particularly known because it was utilized by Joachim Hammerling to reveal that genes are encoded inside the DNA of eukaryotes.

Spiculosiphon Oceana

This big eukaryote can grow up to two inches in length. Its looks and behavior is quite similar to some sponge species. Like some sponges, it creates spicule shells.

Spiculosiphon Oceana is also quite a new discovery, as it was discovered in just 2013 off the Spanish coast. The scientists behind the discovery found the species similarities with sponges quite surprising.

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