In 1800 New England farmers (seeding by hand, with ox-drawn wooden plows and brush harrows, sickles, and flails) needed 150-170 hours of labor to produce their wheat harvest. By 1900 in California, horse-drawn gang-plowing, spring-tooth harrowing, and combine harvesting could produce the same amount of wheat in less than nine hours. In 1800 New England farmers needed more than seven minutes to produce a kilogram of wheat, but less than half a minute was needed in California's Central Valley in 1900, roughly a 20-fold labor productivity gain in a century.
Only a tiny part of the incoming radiant energy, less than 0.05%, is transformned by photosynthesis into new stores of chemical energy in plants, providing the irreplaceable foundation for all higher life
A telling comment on the complexities of energy transformations - we understood how to release nuclear energy sooner (theoretically by the late 1930s, practically by 1943, when the first reactor began to operate) than we knew how photosynthesis works (its sequences were unraveled only during the 1950s).
Several first principles underlie all energy conversions. Every form of energy can be turned into heat, or thermal energy. No energy is ever lost in any of these conversions. Conservation of energy, the first law of thermodynamics, is one of the most fundamental universal realities. But as we move along conversion chains, the potential for useful work steadily diminishes.
This inexorable reality defines the second law of thermodynamics, and entropy is the measure associated with this loss of useful energy. While the energy content of the universe is constant, conversions of energies increase its entropy (decrease its utility). A basketful of grain or a barrelful of crude oil is a low-entropy store of energy, capable of much useful work once metabolized or burned, and it ends up as the random motion of slightly heated air molecules, an irreversible high-entropy state that represents an irretrievable loss of utility.
This unidirectional entropic dissipation leads to a loss of complexity and to greater disorder and homogeneity in any closed system. But all living organisms, whether the smallest bacteria or a global civilization, temporarily defy this trend by importing and metabolizing energy. This means that every living organism must be an open system, maintaining a continuous inflow and outflow of energy and matter. As long as they are alive, these systems cannot be in a state of chemical and thermodynamic equilibrium.
Their negentropy—their growth, renewal, and evolution-results in greater heterogeneity and increasing structural and systemic complexity. As with so many other scientific advances, a coherent understanding of these realities came only during the nineteenth century, when the rapidly evolving disciplines of physics, chemistry, and biology found a common concern in studying transformations of energy.