The Boring Billion, a slingshot for Complex Life on Earth

Abstract

The period 1800 to 800 Ma (“Boring Billion”) is believed to mark a delay in the evolution of complex life, primarily due to low levels of oxygen in the atmosphere. Earlier studies highlight the remarkably flat C, Cr isotopes and low trace element trends during the so-called stasis, caused by prolonged nutrient, climatic, atmospheric and tectonic stability. In contrast, we suggest a first-order variability of bio-essential trace element availability in the oceans by combining systematic sampling of the Proterozoic rock record with sensitive geochemical analyses of marine pyrite by LA-ICP-MS technique. We also recall that several critical biological evolutionary events, such as the appearance of eukaryotes, origin of multicellularity & sexual reproduction, and the first major diversification of eukaryotes (crown group) occurred during this period. Therefore, it appears possible that the period of low nutrient trace elements (1800–1400 Ma) caused evolutionary pressures which became an essential trigger for promoting biological innovations in the eukaryotic domain. Later periods of stress-free conditions, with relatively high nutrient trace element concentration, facilitated diversification. We propose that the “Boring Billion” was a period of sequential stepwise evolution and diversification of complex eukaryotes, triggering evolutionary pathways that made possible the later rise of micro-metazoans and their macroscopic counterparts.

Recycled selenium in hot spot–influenced lavas records ocean-atmosphere oxygenation

“…This "lost-and-resurfaced" abyssal Se record complements the shallower marine pyrite record preserved on Earth's surface, which was used for reconstruction of the ocean-atmosphere redox evolution (Fig. 5, C and E) (7,19,28 g/g (1s) for the recycled pyrite. This range depends on the relative contributions of pyrite and other matrices (organic matter, clay, and other silicates) to bulk Se budget in global black shales (section S5 and Fig.…”

Oxygen, evolution and redox signalling in the human brain; quantum in the quotidian

“…), though this has recently been contested given that numerous critical biological evolutionary events, such as the appearance of eukaryotes, origin of multicellularity and sexual reproduction and the first major diversification of eukaryotes, occurred during this period, triggering evolutionary pathways that facilitated the later rise of micro‐metazoans and their macroscopic counterparts (Mukherjee et al . ). Furthermore, the concept of a two‐step transition from a virtually anoxic environment to present day conditions has been challenged by the suggestion of a more gradual increase in O 2 levels, termed the Great Oxidation Transition (Lyons et al .…”

“…Figure 1A illustrates the major evolutionary and developmental events that have been inextricably linked to atmospheric O 2 'pulses' over two oxidation events, the Great Oxidation Event (GOE) and Neoproterozoic Event (NOE), interspersed by the Boring Billion, a period between ß1.8 and 0.8 Gya ago in Earth's history characterised by geobiological stasis (an unchanging pattern of atomic isotopes and redox states) and unremarkably stable atmospheric and oceanic O 2 levels (Holland, 2006). This lack of O 2 has been linked to a delay in the evolution of complex life (Lyons et al 2014), though this has recently been contested given that numerous critical biological evolutionary events, such as the appearance of eukaryotes, origin of multicellularity and sexual reproduction and the first major diversification of eukaryotes, occurred during this period, triggering evolutionary pathways that facilitated the later rise of micro-metazoans and their macroscopic counterparts (Mukherjee et al 2018). Furthermore, the concept of a two-step transition from a virtually anoxic environment to present day conditions has been challenged by the suggestion of a more gradual increase in O 2 levels, termed the Great Oxidation Transition (Lyons et al 2014).…”

A review of biotic signatures within the Precambrian Vindhyan Supergroup: Implications on evolution of microbial and metazoan life on Earth

“…A large part of the Precambrian biosphere was dominated entirely by the microbiota and devoid of any major biological evolution, hence it is considered to be 'boring billion' (1.8-0.8 Ga) (Brasier and Lindsay, 1998;Mukherjee et al, 2018). The sedimentary records of the early biotic signatures are poorly preserved, and therefore scientists search for indirect evidence of early life.…”