The Origins of Evolutionary Innovations - A Theory of Transformative Change in Living Systems
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Interesting. How nature innovates?
If you want to have a good invention, have a lot of them.
-- Attributed to T.A. Edison
CHAPTER 1 - Introduction
The history of life is a history of innovations. We are all familiar with countless examples, but are there principles behind them? Is there a property that facilitates innovations, regardless of their physical manifestation?
Every macroscopic organism has visible traits that were dramatic, transformative innovations when they first became fully formed. They changed not only organismal lifestyles, but also the future evolutionary path of life. Examples include plants with flowers, animals with a hard skeleton, birds and insects with wings, organisms living in groups, and, most fundamen- tally, multicellularity itself. Others include teeth to digest hard foodstuffs, vascular systems of plants and animals, syringes to deliver venoms, the endosperm storage tissues of seeds, and the silk production of arthropods.
Underneath this surface of macroscopically visi- ble innovations is a universe of microscopic and submicroscopic innovations. Ultimately, they are the basis of all macroscopic innovations.
An exam- ple is oxygen-producing photosynthesis. It origi- nated with light-harvesting molecules that can split water to produce oxygen, and with mechanisms to incorporate carbon dioxide into biomass. By allow- ing oxygen to accumulate in the atmosphere, it changed not only the entire geochemistry of the planet, but also the future trajectory of life.
It permitted the macroscopic innovations of higher plant life, and ultimately supports most of the 1000 billion tons of biomass that exist today on earth
Other similarly profound innovations involve the ability of organisms to thrive on unusual (for us) food sources, such as minerals, natural gas, or crude oil; the ability to synthesize keratins, a critical component of the outer covering of many animals, such as the scales of reptiles, the feathers of birds, and the hairs of mammals; the ability to incorporate gaseous nitrogen—an otherwise growth-limiting element for many plants—directly into biomass; the origin of myelin, an electrical insulator that allows mammalian neurons to conduct electrical signals efficiently, and that may have promoted the evolu- tion of complex brains.
Towards a theory of innovation
During Charles Darwin’s era, molecular innovations were inaccessi- ble to science. In his theory of evolution by natural selection, Darwin thus focused on complex macro- scopic innovations, such as our eyes, “organs of extreme perfection and complication,”
Darwin empha- sized his conviction that such complex innovations could evolve from simpler antecedents through grad- ual variation that is preserved by natural selection. Since then, eyes have become a textbook example of evolutionary innovation. We now know that they have evolved multiple times independently.
As the geneticist Hugo de Vries put it in 1904 , “Natural selection may explain the survival of the fittest, but it cannot explain the arrival of the fittest.”
This question about the origins of new things is still fundamen- tally unanswered. What is it about life that allows innovation through random changes in its parts?
150 years later, we are in a completely different position. We understand the nature of genotypes, the genetic material (DNA or RNA) of organisms.
These molecules and net- works together ultimately determine all observable characteristics of organisms, their phenotype.