Quote by Yuval Noah Harari

“As the species of the same genus usually have, though by no means invariably, much similarity in habits and constitution, and always in structure,…

— Charles Darwin

Phylogeny and ontogeny are, therefore, the two coordinated branches of morphology. Phylogeny is the developmental history [Entwickelungsgeschichte] of the abstract, genealogical individual; ontogeny, on…

— Ernst Haeckel

“Just as a concept becomes a unit when integrated with others into a wider concept, so a genus becomes a single unit, a species,…

— Ayn Rand

The thing that defines a species is that all members have the same addressing system for their DNA.

— Richard Dawkins

“around, some microbiologists have suggested that classifying bacteria by species is futile. It seems as if all bacteria belong to one mega-species, and different…

— Anne E. Maczulak

Splitting and gradual divergence of genera is exemplified very well and in a large variety of organisms.

— George Gaylord Simpson

“Taxonomy, also called systematics, is the science-based hierarchical classification of the world's species. The area had traditionally been an obscure academic discipline dominated by…

— Stephen J. O'Brien

I had found again and again that the most aberrant population of a species - often having reached species rank, and occasionally classified even…

— Ernst Mayr

We are a naturally hierarchical species.

— Octavia E. Butler

Each species may have had its origin in a single pair, or individual, where an individual was sufficient, and species may have been created…

— Charles Lyell

Established species are evolving so slowly that major transitions between genera and higher taxa must be occurring within small rapidly evolving populations that leave…

— Steven M. Stanley

“Biochemists assume that the three cellular kingdoms evolved from a single common ancestor, because the alternative of supposing an independent origin of life two…

— Phillip E. Johnson