Final answer:
Biogeographic patterns on Earth include the latitudinal gradient of increasing species richness towards the equator, the concentration of small-ranged endemic species in specific regions, and significant endemism in geographically isolated areas such as Australia.
Step-by-step explanation:
The biogeographic patterns on Earth that dictate species richness and composition are influenced by several factors. One of the primary biogeographic patterns is the latitudinal gradient in biodiversity, which follows a general pattern where species richness increases as one moves towards the equator. This is one of the oldest and most consistent patterns observed in biogeography, with nearly all taxonomic groups following this trend. The second pattern involves the concentration of small-ranged species, which are geographically concentrated in areas that may not necessarily have the highest number of species overall but do have a high degree of endemism. The third pattern is related to regions that have been physically isolated by geographic barriers for millions of years, such as Australia, where there is a significant number of endemic species found only in those regions.
These patterns reflect both historical and contemporary processes such as speciation rates, dispersal capabilities, and the availability of diverse habitats. They also highlight the uniqueness of different biogeographic regions around the globe, and the importance of preserving such areas due to their high levels of endemic and threatened species.