Table 5. The various components of Neotropical biodiversity, examples of major aspects known about them, and some of the key topics that remain to be understood.

Biodiversity components	Known knowns	Known unknowns	Unknown unknowns
Taxonomic diversity	Approximate species numbers for macroscopic organisms; human impacts tend to decrease overall diversity	Large portions of biodiversity are unexplored (i.e., microbes, invertebrates, fungi)	Taxonomic units used in biodiversity studies may not represent comparable ecological or evolutionary units
Genetic variation (within species)	Patterns of genetic variation known for very selected taxa	Overall patterns of genetic variation	How generalizable are conclusions drawn by such limited patterns of genetic diversity
Phylogenetic diversity	General understanding of the tree (or network) of life	Drivers of diversification	Potential biases in phylogeny reconstruction and time-calibration
Spatial patterns of diversity	Hotspots and general patterns of species richness and diversity; broad species ranges for charismatic taxa	Areas of endemism; known patterns of biodiversity are biased; ecological preferences of species; drivers of diversity	Human impact to overall spatial patterns
Functional diversity	Large scale productivity patterns	Biotic interactions	Relevance of current functional diversity measures; equivalency in functional traits; relationship between current and future functional diversity