The fossil record of early eukaryotic diversification

The Fossil Record of Early Eukaryotic Diversification

The Cambrian explosion can be thought of as the culmination of a diversification of eukaryotes that had begun several hundred million years before. Eukaryotes – one of the three domains of life — originated by late Archean time, and probably underwent a long period of stem group evolution during the Paleoproterozoic Era. A suite of taxonomically resolved body fossils and biomarkers, together wi...

Estimating diversification rates from the fossil record

Diversification rates are estimated from phylogenies, typically without fossils, except in paleontological studies. By nature, rate estimations depend heavily on the time data provided in phylogenies, which are divergence times and (when used) fossil ages. Among these temporal data, fossil ages are by far the most precisely known (divergence times are inferences calibrated with fossils). We pro...

Fossil embryos deep in the fossil record

Embryos have been found in ‘old’ rocks on four continents, especially in Siberia, Nevada, Australia and China. They have been discovered in sedimentary rocks of even Late Neoproterozoic age, assuming the evolutionary geological column1 (figure 1). The Neoproterozoic is the period, so called, between 1 billion and 550 million years ago. This discovery was in the Doushantuo Formation, Guizhou Pro...

The Primate Fossil Record

Oxygen-collagen priority and the early metazoan fossil record.

The thesis is developed that a low oxygen level Precambrian atmosphere presented early-evolving metazoan organisms with physiological connective tissue priorities resulting from the important molecular oxygen requirements in the biosynthesis of collagen hydroxyproline. Shells, cuticles, and carapaces which are not mandatory metazoan prerequisites but which directly or indirectly demand substant...