Protists are a diverse group of eukaryotic creatures, meaning they have a nucleus, organelles, and a cell membrane. These guys, on the other hand, are unique. Even though they aren’t technically plants, animals, or fungi, they have many traits with other eukaryotic life forms. A protist is an organism that cannot be classified into any of the other kingdoms based on its morphological or genetic characteristics. Plant-like protists, for example, aren’t close enough to plants to qualify as such.
Plants Like Protists
The ability to do photosynthesis is what distinguishes algal protists (also known as “algae”) from plants. Plant-like protists have chloroplasts, which contain the pigment chlorophyll, which gathers and transforms light into energy, just like plants do. Algal protists can be green, but they can also be red, brown, or gold. Their colours derive from pigments that hide chlorophyll’s green colour.
Understandably, small, swimming organisms aren’t welcomed to the plant table; after all, when was the last time you saw a tiny swimming tree? But what about the seaweed? Even though seaweeds have leaves, stalks, and roots, they are not allowed in the plant club. Plant-like protists are simply protists in disguise, no matter how much they resemble plants.
A closer examination reveals that these organisms are only superficially similar to plants. Pine needles have many different sorts of cells, as demonstrated in the photographs here. Plants, for example, have external cells that protect them in the same way as our skin does. Algal protists are clumps of cells wrapped in a slimy layer known as the extracellular matrix (ECM), which you can see on your computer right now.
Unicellular Plant-Like Protists
There are billions of minute animals floating around in pond water, including many unicellular plant-like protists like Chlamydomonas and Euglena. Because this and other minuscule algae have no resemblance to plants, it’s easy to see why they aren’t considered plants. However, enormous unicellular protists such as the seaweed Caulerpa may be found deep within the dirt and muck. These enormous animals can reach a height of two feet (60 cm), but they are still just one cell. What’s more amazing is that when Caulerpa begins to grow, each organism can produce up to 5,000 leaves that all belong to the same cell. Unfortunately, Caulerpa is a single cell, no matter how much it resembles a plant. As a result, it isn’t a plant and cannot be placed on the plant table.
Multicellular Plant-like Protists
Multicellular algae are organisms made up of two or more cells that function as one. If you observe pond scum forming in the water, it’s probably because there are multicellular algae present. Multicellular algae, like unicellular plant-like protists, can be gigantic or minute.
Colonial algae are clusters of algae implanted in an ECM that can take on a variety of morphologies, such as leaves, roots, and stems. Volvox is a type of microscopic colonial algae that has a ball-like appearance. Ulva may resemble a plant, but they are little more than a clump of algae cells caught in slime, much like the Volvox.
While colonial plant-like protists can take on a variety of morphologies, filamentous algae create lengthy chains of cells linked by their cell walls and an extracellular matrix (ECM). They resemble long strands of spaghetti with green cells crammed inside. Some filamentous algae even resemble plants, but because they don’t create specialised tissues, they’re just clever algal disguise artists and can’t be considered plants.
Conclusion
We conclude that Photosynthesis is used by plant-like protists to synthesise over half of the oxygen on the earth. Other protists break down and recycle nutrients required for human survival. Protists make up a significant portion of the food chain.