Concepts

Viroids are the smallest known infectious pathogens in the world. It is composed of a short strand of circular, single stranded RNA but protein coat is absent.

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Points to Remember Viroids are subtype […]

If no holotype was designated, then any one of two or more specimens that is listed known to be syntype

Number of variety of species that are represented in a given community

Sexual reproduction is fusing of two morphologically distinct types of specialized reproductive cells

Sexual Reproduction Explanation

It involves a female’s large ovum (or egg) and a male’s smaller sperm

Unicellular organism that do not have a membrane – bound nucleus (karyon), mitochondria and other membrane-bound organelle

Introduction of contaminants into the natural environment that is causing adverse changes in the environment

Distinguishing different types of organisms that considers all relevant criteria

Level in taxonomic rank below kingdom and above Class

Phylum Explanation

In botany the term division has been used instead of phylum

Forming a single branch of the “tree of life” based on the smallest group of individuals with a common ancestor

Other than the holotype or isotype if any specimen is cited in the protologue it is known to be as paratype