Significance of Protists

The vast majority of living organisms in the world can be broadly classified into six kingdoms, those being Animalia, Plantae, Fungi, Archaea, Bacteria, and Protista. The Protista kingdom houses the organisms that usually do not fall under any of the other classifications. They are usually microscopic and are made up of a single cell (unicellular). In this article, we will learn about the significance of the protists, the different types of organisms under them, as well as the characteristics that make them a member of this kingdom.

Types of Protists

Protists are divided into broadly three categories- animal-like protists, plant-like protists and fungi-like protists (also called the protozoa the algae and the moulds) How the protist acquires their food forms the basis of this classification. The protists can of course be divided based on several diverse factors like size, shape, the structure of the nucleus, types of organelles, etc., and the similarities it shares with other kingdoms highlight the significance of the protists. Protists reproduce both sexually and asexually, and most of them are aquatic when it comes to their habitat. Some of the protists, however, are parasitic, and thus live inside the body of their host.

The Animal Kingdoms

The six animal kingdoms are as follows:

Archaea: These are primitive single-celled organisms (or prokaryotes) with RNA as their cell wall helps them to survive in difficult conditions like hot springs.

Eubacteria: These organisms are considered to be “true” in nature. They are of various shapes and sizes and can be found in many diverse places. Although a lot of bacteria harmlessly live in our bodies, some bacteria can be harmful and cause diseases.

Fungi: The main difference between fungi and most other kingdoms is that fungi have chitin inside their cell walls. They can be microscopic, single-celled in nature, or even multicellular like mushrooms. Fungi release chemicals to break down organic matter around them, which is then consumed as food.

Plantae: This, of course. Refers to the plants. Plants are characterized by the fact that they are usually multicellular, and have a green pigment called chlorophyll, which they use to synthesize food.

Animalia: The animal kingdom. The organisms in this group can range from unicellular to multicellular, and depend on other organisms for nutrition. Animals are further divided into chordates(animals with a spinal cord) and non-chordates (animals without a spinal cord

Protista: Protists are unicellular, and share similarities with most of the kingdoms. They mark the point in evolution where the well-defined nucleus in a unicellular organism was first seen. This is one of the explanations as to what is special about protists.

Characteristics of Protists

Here are some characteristics of protists:

Protists are eukaryotic, i.e. their cells have a well-differentiated nucleus, as well as other organelles. These organelles are membrane-bound, which means that they are separated from the cell cytoplasm by membranes, and are differentiated as specialized for particular jobs.

Protists possess a mitochondrion- a special organelle that has the responsibility of turning imbibed nutrition into energy for the cell to use.

Protists are usually aquatic when it comes to habitat. Some of them live in moist soil as well, and the parasitic protists live in the body of the host.

The vast majority of protists are unicellular, with a few exceptions. Kelp, for example, is multicellular and can grow up to a hundred feet tall.

When it comes to nutrition, protists can be autotrophic (makes their food through photosynthesis), heterotrophic (depends on other organisms for food) and symbiotic (exists in synthesis with another organism, providing shelter in exchange for food)

Protists exhibit special organs for locomotion like cilia or flagella which they use to move around. A lot of them also have pseudopodium or “false feet” for moving around.

Protists usually reproduce asexually, but when under stress, or in extremely rare cases, they participate in sexual reproduction.

For examples Amoeba proteus, Euglena gracilis, Paramecium aurelia and more.

Importance of Protists

To understand the importance of kingdom Protista, one must look at the various ways in which they have come to our use. The place they hold in evolutionary history also emphasizes the significance of the protists, as they form an integral component in researching the world’s natural history.

The advent of protists (about two billion years ago) marks the first time a well-defined nucleus and membrane-bound cell organelles were seen. This hints at the earlier stages of cells slowly forming multicellular organisms, and then developing into the complex and advanced human cell.

Through the process of photosynthesis, plant-like protists or algae release almost half of the total amount of oxygen on earth

Many protists are used in medical research to make medicines for arthritis, blood pressure, digestion problems, etc.

They also form a huge part of scientific research. Some protists are used to study the implementation of chemical signals within the cells for performing different tasks.

Conclusion

We as human beings have to acknowledge the huge amount of help and indirect guidance we get from other organisms. The huge significance of protists in our lives- an organism that is so small that it is invisible to us- is a true testimony of this. It is a humbling thought that humans have lived on the earth with the help of others, no matter how advanced we become.