Anecdotal observations by John Thomas

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Eukaryot:  Eukaryotes are organisms whose cells have a nucleus enclosed within membranes, unlike prokaryotes (Bacteria and Archaea), which have no membrane-bound organelles.  Eukaryotic cells also contain other membrane-bound organelles such as mitochondria.

Unlike unicellular archaea and bacteria, eukaryotes may also be multicellular and include organisms consisting of many cell types forming different kinds of tissue. Animals and plants are the most familiar eukaryotes.

Prokaryot: A prokaryote is usually a unicellular organism, sometimes a multi-cellular organism, that lacks a membrane-bound nucleus, mitochondria, or any other membrane-bound organelle.

Protist: any eukaryotic organism contains a nucleus, but is not an animal, plant or fungus. Protists do not form a natural group since they exclude certain eukaryotes; but, like algae or invertebrates, they are often grouped together for convenience

Protists do not have much in common, and are considered similar-appearing but diverse biological groups that do not have an exclusive common ancestor, but are composed of eukaryotes with different life cycles, trophic levels, modes of locomotion and cellular structures.

Bacteria: [singular]; bacterium [plural] us a type of biological cell that constitute a large domain of prokaryotic microorganisms of different shapes ranging from spheres to rods and spirals.

Virus: a small infectious agent that replicates inside the living cells of an organism. Viruses can infect all types of life forms, from animals and plants to microorganisms, including bacteria and archaea.

Archaea: single cell organisms that have no cell nucleus, as opposed to bacteria that contain a nucleus.

Parasite: an organism that exploits and lives off of a host.

Symbionts: different organisms that assist each other in either an obligatory or facultative fashion, meaning each is required for the other to live, or each merely assist each other, but can live independently.

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