A small number of cactus species in the tribes Hylocereeae and Rhipsalideae have become adapted to life as climbers or epiphytes, often in tropical forests, where water conservation is less important.
Second, all four appear to have become adapted for arboreal life, as in the lower primates, the "four-handed folk".
To the extent that the evolutionary viewpoint emphasized the processes by which individuals become adapted to their environment, as in the teachings of the English philosopher Herbert Spencer, their influence was profoundly conservative.
Coevolution between birds and fruit-bearing plant species is even more complicated than that between flowers and pollinators or between models and mimics, because so many plant species have evolved fleshy fruits for dispersal by birds and so many bird species have become adapted to eat fruits as part of their diets.
These junction zones often contain species of each of the overlapping communities as well as some species that have become adapted specifically for living in these zones.
As organisms become adapted to their environments through their habits, modifications occur.
Community structure can become stratified both vertically and horizontally during the process of succession as species become adapted to their habitat.
This form of allopatric speciation is particularly apparent when colonizers reach geographically remote areas, such as islands, where they find few or no competitors and have an opportunity to diverge as they become adapted to the new environment.
Similarly, Gagneux et al. have recently proposed that the major M. tuberculosis lineages have evolved so as to become adapted to specific host genetic backgrounds and are much more likely to transmit and cause disease among patients of the same ethnicity [ 36].
As some insects become adapted to these metabolites, interactions between the two groups of organisms occasionally lead to highly specific relationships, as in the case of M. aquatica and the herbivore Chrysolina herbacea.
