Species Definition ·Eukaryotic species: A group of closely related organisms that breed among themselves Prokaryotic species: A population of cells with similar characteristics Clone:Population of cells derived from a single cell Strain:Genetically different cells within a clone 。Viral species: Population of viruses with similar characteristics that occupies a particular ecological nicheSpecies Definition • Eukaryotic species: • A group of closely related organisms that breed among themselves • Prokaryotic species: • A population of cells with similar characteristics • Clone: Population of cells derived from a single cell • Strain: Genetically different cells within a clone • Viral species: • Population of viruses with similar characteristics that occupies a particular ecological niche