In biology, the strain is a low-level taxonomic rank used in different contexts:
In microbiology, a strain is a part of a bacterial species different from other bacteria of the same species by a minor but identifiable difference. Strains are often created in the laboratory by mutagenesis existing strains or wild-type examples of bacterial species.
In zoology, a strain corresponds to an individual or group of individuals who are at the origin of a line of descendants, sometimes called the holotype, paratypes, etc. A strain is a population of organisms that descends from a single organism or pure isolate culture. Strains of the same species may differ slightly from each other in many respects.
A strain thus consists of a group of organisms of the same species possessing certain differential traits based on their relationship; either they come from the same region, as the same watershed of a river, or they are the fruit of a particular breeding program (exists as a whole interbreeding without introductions from external sources).
<span>Algae is a prime example of a pioneer species that would be found where a glacier has retreated, because the glacial retreat allows for its growth. This process is called succession and usually starts with lichen, an relative of algae. Lichen grows on bare rock which is left behind. Afterwards, acids produced in this environment cause dirt and soil to be created.</span>
The pentose sugars ribose and deoxyribose are part of the nucleotides that make up the crucial nucleic acids like DNA and RNA .