Chromists

The kingdom Chromista is almost entirely comprised of aquatic, photosynthesising eukaryotic organisms[1]. They include diatoms, dinoflagellates, and a number of algae species such as golden-brown algae, brown algae, and yellow-green algae[1]. Their ability to photosythesise makes them key primary producers in a variety of aquatic systems, much like plant species[5]. However, even though chromists often share photosynthesis as a common process for deriving energy, they are distinctly different from plants.

Quick fact

Chromists can range in size

from unicellular organisms (diatoms) all the way up to kelps that can grow to tens of metres in length (brown algae)[4]

Chromista physical features

Chromists possess physical features that are unique to their kingdom and, as a result, are crucial in differentiating them from other biota. All chromists have flagellated cells in at least some portion of their life cycle, and they typically contain chlorophyll–a and –c, as opposed to chlorophyll–a and –b, which is the chlorophyll composition normally found in plant and green algae species[3]. Chromists also have cell structure characteristics that physically separate them from other eukaryotes such as rough endoplasmic reticulum-bound chloroplasts and nuclei, tubular cristae in their mitochondria and, commonly, the ability to manufacture calcium carbonate or silica skeletons via their golgi apparatus[2].

Additional information:

• WildNet Species Search - Chromists
• Atlas of Living Australia - Chromista

References

1. ^ a b Cavalier-Smith, T (2018), 'Kingdom Chromista and its eight phyla: a new synthesis emphasising periplastid protein targeting, cytoskeletal and periplastid evolution, and ancient divergences', Protoplasma, vol. 255, pp. 297-357.
2. ^ Maneveldt, GW & Keats, DW (1997), 'The Chromista', Engineering in Life Sciences. [online] Available at: https://repository.uwc.ac.za/bitstream/handle/10566/1234/ManeveldtChromista1997.pdf?sequence=1&isAllowed=y.
3. ^ Mysliwa-Kurdziel, B, Latowski, D & Strzalka, K (2019), 'Chapter Three - Chlorophylls C-Occurence, synthesis, properties, photosynthetic and evolutionary significance', in Advances in Botanical Research, vol. 90, pp. 91-119.
4. ^ University of California Museum of Paleontology (2011), Introduction to the Chromista. [online] Available at: https://ucmp.berkeley.edu/chromista/chromista.html.
5. ^ Yoon, HS, Hackett, JD, Pinto, G & Bhattacharya, D (2002), 'The single, ancient origin of chromist plastids', PNAS, vol. 99, no. 24, pp. pp.-15507 - 15512.

Last updated: 5 October 2023