Читать книгу Principles of Microbial Diversity - James W. Brown - Страница 21

Underlying all of these different aspects of diversity is genetic diversity, perhaps more specifically viewed as evolutionary diversity. Microbes are far more evolutionarily diverse than are macroscopic creatures; the macroscopic world is just the tip of the iceberg of life. Even most plants and animals are microscopic! So microbial diversity is actually the same as biological diversity, with just a few of the more ponderous organisms overlooked.

Evolutionary diversity is usually expressed in terms of trees: branched graphs that trace the genealogies of organisms (Fig. 1.9). When these trees are based on genetic diversity (gene sequences), they can be both quantitative and objective.

This is the perspective on diversity we are using in this book.

Figure 1.9 Phylogenetic tree of representative organisms based on small-subunit rRNA sequences. (Redrawn from an image provided by Norman R. Pace.) doi:10.1128/9781555818517.ch1.f1.9