When we think of unicellular or single-celled organisms, we usually think of microorganisms that are not visible to the naked eye. We may not be wrong in thinking so because most of the unicellular organisms are extremely tiny and can be seen only through microscopes. But there are certain single-celled organisms that are visible to us, and some can grow to be even a foot long. Surprised? Come, let’s find out more about one such organism.
They’re macroscopic
Single-celled organisms that are visible to the naked eye are called macroscopic unicellular organisms. Specific types of amoeba, bacteria, and algae fall under this category. One such organism is Ventricaria ventricosa. Also known as bubble algae and sailors eyeball, they are considered one of the largest single-celled organisms. Earlier called Valonia ventricosa, this spherical algal species can grow to even five cm in diameter. They are found in the tropical oceans, and are seen in coral rubble.
Though they come in shades of green, in water they appear darker or silver-coloured.
Just like some such single-celled organisms, these algae have just one cell but several nuclei. Meaning, in the original cell, there is division of the nucleus, but not the division of cytoplasm (the thick fluid in the cell). The division of cytoplasm is what gives rise to more cells in multi cellular organisms. The division the nucleus helps the bubble algae grow large enough to be visible to the human eye. In addition, they are also said to have a large central vacuole – a space within a cell that does not contain cytoplasm – which could play a role in their size.
Picture Credit : Google