What is the Difference Between Chromista and Protista

The key difference between chromista and protista is that chromista is a biological kingdom comprised of unicellular or multicellular eukaryotic species such as algae, diatoms, oomycetes, and protozoans, while protista is a biological kingdom comprised of unicellular eukaryotic species such as protozoa, protophyta, and molds.

Understanding the relationships in an aquatic food web is very important for the survival of an ecosystem. Some small and large organisms, including bacteria, fungi, plants, animals, protista, and chromista, make their homes in aquatic ecosystems. Protista and chromista are usually grouped under plankton. Hence, the plankton group consists of both unicellular and multicellular eukaryotic species.

CONTENTS

1. Overview and Key Difference
2. What is Chromista  
3. What is Protista
4. Similarities – Chromista and Protista
5. Chromista vs Protista in Tabular Form
6. Summary – Chromista vs Protista

What is Chromista?

Chromista is a biological kingdom that consists of unicellular or multicellular eukaryotic species such as algae, diatoms, oomycetes, and protozoans. It is a biological kingdom that was created by British biologist Thomas Cavalier Smith in 1981. Initially, algae were the only group included in this group. But later, some protozoans also were included, and new kingdoms such as Plante and Animalia were created. Chromista contains the following groups: heterokonts, haptophytes, and cryptomonads. The species in this group contain photosynthetic organelles called plastids. Plastids have photosynthetic pigments such as chlorophyll c. Their plastids are surrounded by flour membranes. It is believed that they acquired the plastids from some red algae.

Figure 01: Chromista Structure

The members of chromista contain basic features like possessing plastids and cilia. The plastids lie within an extra periplastid membrane in the lumen of the rough endoplasmic reticulum. The cilia are either tripartite or bipartite rigid tubular hairs like structures. Through evolution, many have retained plastids and cilia, while some have lost them. Moreover, the diversity of chromista stems from degeneration, replacement, or loss of their plastids in some lineages. Kelp, seaweeds, brown algae, and red algae are some popular members of this kingdom.

What is Protista?

Protista is a biological kingdom that consists of unicellular eukaryotic species such as protozoa, protophyta, and molds. This term was first coined by Ernst Haeckel in 1866. Protista is traditionally subdivided into three groups: protozoa, protophyta, and molds. Protozoa subgroup contains unicellular animal-like organisms such as flagellata, cilophora, amoeba and sporozoa. Protophyta subgroup is composed of autotrophic organisms like unicellular algae, dinoflagellates, and Euglena like flagellates. Molds usually refer to fungi. But slime molds and water molds are fungi like saprophytic protists.

Figure 02: Protista – Dinobryon

However, some protists have been considered to be both protozoa and algae or fungi. They are called ambiregnal protists. Protists do not have much in common besides their relatively simple levels of the organization. Furthermore, in cladistic classification system, there is no equivalent to the taxa protista. It is generally a popular paraphyletic group in the classification.

What are the Similarities Between Chromista and Protista?

  • Protista and chromista are usually grouped under plankton and they are two biological kingdoms.
  • They contain eukaryotic organisms.
  • Both kingdoms contain organisms that have chlorophyll pigments.
  • They contain heterotrophic and autotrophic organisms.

What is the Difference Between Chromista and Protista?

Chromista is a biological kingdom of unicellular or multicellular eukaryotic species such as algae, diatoms, oomycetes, and protozoans, while Protista is a biological kingdom of unicellular eukaryotic species such as protozoa, protophyta, and molds. So, this is the key difference between chromista and protista. Furthermore, the chromista kingdom has organisms that have chlorophyll a, b, c, d, carotenoids, and phycobilin pigments, while Protista kingdom has organisms that have chlorophyll a, b, and c pigments.

The following tabulation presents a side by side comparison of the difference between chromista and protista.

Summary – Chromista vs Protista

Protista and chromista are normally grouped under plankton. They are eukaryotic species. Chromista is a biological kingdom that consists of unicellular or multicellular eukaryotic species such as algae, diatoms, oomycetes, and protozoans. Protista, on the other hand,  is a biological kingdom that consists of unicellular eukaryotic species such as protozoa, protophyta, and molds. Thus, this is the summary of the difference between chromista and protista.