Our stadium of four million

Four million years of African herbivory.

The vast African continent is an ecological stage with ever-changing scenery and casts of characters that included human ancestors. The mammals that came and went upon this stage have been enlisted to help answer a compelling question relevant to our own evolutionary story: How do land animals respond to long-term environmental change? The paper by Cerling et al. (1) is a milestone in this ques...

Finding Four Million Large Random Primes

Nearly four million Californians are food insecure.

Food insecurity has increased significantly among low-income Californians over the last decade. According to data from the 2009 California Health Interview Survey, 3.8 million adults in households with incomes at or below 200% of the Federal Poverty Level (FPL) could not afford enough food at least once in the previous year. Low-income households with children and Spanish-speaking households su...

The first four million years of human evolution.

In one of the last paragraphs of The origin of species (1859), Darwin famously suggested that ‘Much light will be thrown on the origin of man and his history’. When he published The descent of man 12 years later, there was still no fossil evidence of our earliest evolutionary history, and nothing at all from the African continent. Yet our close biological relationship to the great apes, and esp...

Four hundred million years of silica biomineralization in land plants.

Biomineralization plays a fundamental role in the global silicon cycle. Grasses are known to mobilize significant quantities of Si in the form of silica biominerals and dominate the terrestrial realm today, but they have relatively recent origins and only rose to taxonomic and ecological prominence within the Cenozoic Era. This raises questions regarding when and how the biological silica cycle...