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All eukaryotes apart from animals, plants and fungi are considered protists. [1] Its field of study therefore overlaps with the more traditional disciplines of phycology , mycology , and protozoology , just as protists embrace mostly unicellular organisms described as algae , some organisms regarded previously as primitive fungi , and protozoa ...
A protist (/ ˈ p r oʊ t ɪ s t / PROH-tist) or protoctist is any eukaryotic organism that is not an animal, land plant, or fungus.Protists do not form a natural group, or clade, but are a polyphyletic grouping of several independent clades that evolved from the last eukaryotic common ancestor.
A protist (/ ˈ p r oʊ t ɪ s t /) is any eukaryotic organism (one with cells containing a nucleus) that is not an animal, plant, or fungus.The protists do not form a natural group, or clade, since they exclude certain eukaryotes with whom they share a common ancestor; [a] but, like algae or invertebrates, the grouping is used for convenience.
Since protists are eukaryotes (and not prokaryotes) they possess within their cell at least one nucleus, as well as organelles such as mitochondria and Golgi bodies. Many protist species can switch between asexual reproduction and sexual reproduction involving meiosis and fertilization. [6]
Protists are distributed across all major groups of eukaryotes, including those that contain multicellular algae, green plants, animals, and fungi. If photosynthetic and fungal protists are distinguished from protozoa, they appear as shown in the phylogenetic tree of eukaryotic groups.
The dinoflagellate nucleus was termed 'mesokaryotic' by Dodge (1966), [36] due to its possession of intermediate characteristics between the coiled DNA areas of prokaryotic bacteria and the well-defined eukaryotic nucleus. This group, however, does contain typically eukaryotic organelles, such as Golgi bodies, mitochondria, and chloroplasts. [37]
The tree of life. Two domains of life are Bacteria (top branches) and Archaea (bottom branches, including eukaryotes). The two-domain system is a biological classification by which all organisms in the tree of life are classified into two domains, Bacteria and Archaea.
In contrast to prokaryotic cells, eukaryotic cells are highly organised. Prokaryotes are the bacteria and archaea, while eukaryotes are the other life forms — protists, plants, fungi and animals. Protists are usually single-celled, while plants, fungi and animals are usually multi-celled.