1. Diversity among microbes   1.1 How diverse are microbial communities ? Diversity of habitats which selects for biodiversity of microbial communities. Characteristic microbes from specific ecosystems. Spacial heterogeneity: patterns of microbial diversity in soils. Temporal changes of community composition: patterns of diversity in time. Regulation of organismic ecosystem structure: how bacteriaplankton is regulated. Amounts of microbial biomass on earth: human gut contains more prokaryotic cells than the entire body consist of eukaryotic cells. Biogeography and co-evolution of bacterial diversity.   1.2 How can microbial diversity be sampled and quantified? Diversity based on cultivation vs. diversity based on molecular phylogenetic techniques. Basic molecular techniques: PCR of rDNA, cloning and sequencing, single-cell hybridization, etc. Designing primers which anneal to group specific and to universally conserved sequences of 16S-rRNA-genes. Analysis of sequence information: software packages for statistical methods. Known and unknown diversity: how to account for not yet culturable microorganisms.   1.3 Developments in molecular ecology 1970s: Discovery of a hidden diversity, the Archaea domain (kingdom). 1980s: Use of microbial models to test evolutionary hypotheses. 1990s: Application of molecular tools to study microbial diversity in ecosystems: RFLP, T-RFLP, DGGE, FISH, etc.
	microeco