There are countless ways in which ecology and evolution may feed back each other, and biologist have long appreciated how the interplay between ecology and evolution can lead to the generation of biodiversity over relatively long time scale (generally represented as a benching tree with the taxa at the tips of the branches, see below ). Adaptive radiation is a example of how ecological can drive the process of speciation, resulting in an increase in the diversity of form and function  within a community, which in turn has consequences for community and ecosystem processes. Only recently, however, have ecologists come to recognize that evolutionary changes in species traits driven by selection over a relatively few generation can result in eco-evolutionary feedbacks in contemporary time. Eco-evolutionary feedbacks is defined as "the cyclical interaction between ecology and evolution such that changes in ecological interactions drive evolutionary change in organismal traits that, in turn, alter the form of ecological interactions." 

Árvore filogenética

A phylogenetic tree, also known as a phylogeny, illustrates the inferred evolutionary relationships among a groups of organisms (taxa) that are descendent from a common ancestor. The tips represents descendant taxas, A - F at the figure, these are often species, but could be higher taxonomic units such as genera or families. A node represents a taxonomic unit, internal nodes represents shared ancestors and terminal nodes represents contemporaneous species. Speciation events are inferred to occur at the internal nodes. The branches of the tree define the relationships among species; the pattern of branching is referred as the tree's topology.  Branch lengths may or may not have meaning, for exemple if a phylogeny is constructed based on molecular data, such as DNA nucleotide substitutions, then the branch lengths may represent the number of nucleotide substitutions. If the substitutions rate is calibrated by molecular clock, then the branch lengths may represents evolutionary time in years. Most phylogenies includes an outgroup, taxa F at the figure, or distantly taxon, which is useful for rooting the tree and defining the relationship among the taxa of interest.  A monophyletic linage within a phylogeny is called a clade. By definition a clade can be separated from the root of the tree by cutting a single branch two descendent that split from the same node are called sister taxa.   


Community phylogenetics

A phylogeny describes the hypothesized pattern of evolutionary relationship among a set of organism. Although evolutionary relationship and phylogenies have been studied for a very long time, the application of phylogenetic analysis to the study of comparative biology is surprisingly recent, beginning in earnest  in the 1980s. The application of phylogenetics to study of communities is even more recent. A comment by Darwin, however, suggested on of the first application of phylogenetic analysis to community ecology. Darwin noted that closely related species might compete strongly with one another "species of the same genus have usually, though by no means invariably, some similarity in habits and constitution, and ways in structure". In modern parlance Darwin recognized that species' functional traits may be conserved across phylogenies.

If species with similar functional traits use resources and habitat in similar ways, close relatives may therefore compete more strongly with one another than more distant relatives. Thus, we would expect interspecific competition and limiting similarity to lead to communities that contains fewer closely related species than expected by chance. On the other hand, if closely related species have similar environmental requirements and ecological needs, we might expect the selective effects of environmental factors, referred to as habitat filtering, to lead to communities that contain more closely related species than expected by chance.

If strong Interspecific competition determines which species coexist in a community, then we would expect community composition to show phylogenetic over-dispersion; that is, species should be more evenly dispersed in phylogenetic space that would occur by chance. On the other hand if closely related species similar environmental requirements, then we would expect communities contain more closely related species than would occur by chance, or phylogenetic clustering. Thus phylogenetic analysis has the potential to help to resolve this question and reveal the relative importance of competition versus habitat filtering in determining the  species composition communities.

Are closely related species stronger competitors?

Tests of the competitive-relatedness hypothesis to date have yielded mixed results. There have been direct tests of the assumption that closely related species are stronger competitors than distantly related species.