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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.
Many eukaryotes are unicellular; the informal grouping called protists includes many of these, with some multicellular forms like the giant kelp up to 200 feet (61 m) long. [10] The multicellular eukaryotes include the animals, plants, and fungi , but again, these groups too contain many unicellular species . [ 11 ]
The last eukaryotic common ancestor (LECA) is the hypothetical last common ancestor of all living eukaryotes, around 2 billion years ago, [3] [4] and was most likely a biological population. [8] It is believed to have been a protist with a nucleus, at least one centriole and cilium , facultatively aerobic mitochondria, sex ( meiosis and syngamy ...
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.
Eukaryotes have a nucleus in their cells, and include: Protists – many unicellular eukaryotes including malarial parasites, amoeba, and diatoms. [69] Kingdom Fungi – eukaryotes such as mushroom, yeast, and mould; all fungi. Kingdom Plantae – all plants. Kingdom Animalia – all animals.
Sexual reproduction appears to have arisen very early in eukaryotic evolution, implying that the essential features of meiosis were already present in the last eukaryotic common ancestor. [ 71 ] [ 67 ] [ 72 ] In extant organisms, proteins with central functions in meiosis are similar to key proteins in natural transformation in bacteria and DNA ...
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 is any eukaryotic organism (that is, an organism whose cells contain a cell nucleus) that is not an animal, plant, or fungus.While it is likely that protists share a common ancestor, the last eukaryotic common ancestor, [1] the exclusion of other eukaryotes means that protists do not form a natural group, or clade.