A phylogenetic analysis of galaxies in the Coma Cluster and the field: a
  new approach to galaxy evolution
  We propose a phylogenetic approach (PA) as a novel and robust tool to detect
galaxy populations (GPs) based on their chemical composition. The branches of
the tree are interpreted as different GPs and the length between nodes as the
internal chemical variation along a branch. We apply the PA using 30 abundance
indices from the Sloan Digital Sky Survey to 475 galaxies in the Coma Cluster
and 438 galaxies in the field. We find that a dense environment, such as Coma,
shows several GPs, which indicates that the environment is promoting galaxy
evolution. Each population shares common properties that can be identified in
colour magnitude space, in addition to minor structures inside the red
sequence. The field is more homogeneous, presenting one main GP. We also apply
a principal component analysis (PCA) to both samples, and find that the PCA
does not have the same power in identifying GPs.
