From Physorg.com, an example of biogeochemistry where microorganisms contribute to the deposition of sediments. Looking at Angel Terrace in Yellowstone National Park, the rate of precipitation of calcium carbonate (CaCO3) was reduced when there was not microbes. So depending on the layers of limestone, the age of the rock can be determined. Also, the microbes seem to create a pattern in the calcium carbonate crystals.

From EurekaAlert.com, this show the subtle way that changes in form can occur. By mucking about with a gene that regulates limb growth, scientists have created mice with long fore limbs.