Phylogenies for ecologists

1. Molecular genetic information is becoming widely available and can reveal when (in relative or absolute time) pairs of individuals within a species or pairs of higher-level taxa last shared a common ancestor. 2. Such genealogical or phylogenetic information is usually ignored by ecologists when performing cross-taxonomic analyses, probably because ecological and evolutionary time-scales are considered to be very different. 3. Whenever ecologists attempt to understand which traits or characteristics allow different taxa to be successful in different ecological circumstances, phylogenetic information should be incorporated into their analyses whether the data are experimental or observational. Closely related species share many traits in addition to those responsible for ecological success in particular circumstances, and phylogenetically controlled analyses help to eliminate the effects of such confounding variables. 4. When genealogical information is available showing when, in relative time, a sample of individuals from a population or species last shared a common ancestor, it is often possible to infer the population dynamic history. In particular, some modes of population change (e.g. linear or exponential growth, population stasis, population decline) can be shown to provide a much better fit the data than others. 5. Phylogenetic analysis can show the relative extent to which new species evolve into vacant niches rather than partition old niches.