Most people — including most professional biologists — think that one either accepts the neo-Darwinian theory of the universal common ancestry of life via undirected natural causes, or else one is a “creationist,” meaning someone who advocates multiple independent starting points for life, all of them specially created.
In the neo-Darwinian picture (the upper left quadrant), all organisms on Earth share a common ancestor, often abbreviated as “LUCA,” for Last Universal Common Ancestor.
In the horizontal axis of the matrix, this historical geometry is designated as “monophyly” [mono (single) phylum (tribe)]. “Polyphyly” designates a geometry with multiple independent starting points [poly (many) phylum (tribe)].
In the lower right quadrant, one finds the viewpoint diametrically opposed to the single Tree picture, held historically by persons such as the great Swedish botanist Linneaus, or the 19th century Harvard zoologist Louis Agassiz. This view maintains that organisms spring from separate original ancestors, and owe their existence to purposeful design.
But other views are possible, and have been pursued both in the past and today by prominent biologists. In the upper right quadrant, evolutionary theoreticians argue that life came to be via strictly natural causes, but did so multiple times, and some of those independent lineages survive to the present. In the lower left quadrant, by contrast, one finds those scientists who support the single-tree-of-life picture, but who also argue that design (of some form) is necessary for life’s existence.
ASA is the American Scientific Affiliation, a group of Christians in the sciences. CRS is the Creation Research Society, another group of Christians in the sciences, who support special creation as a scientific theory.