c. 4.6 billion years ago (“bya”)

Back in life’s early days, some creatures discovered another source of energy and nutrients besides the chemical brew of volcanic vents: other life forms. Predation was then born. Evolution has plenty to answer for, and opportunistically robbing creatures of their lives to eat them is perhaps evolution’s primary “negative” outcome.

Below is a diagram of two hydrogen atoms before and after reaction, as they bond to form H2.

From their through their and in the Eocene, primates continued evolving. About 35 mya, and monkeys, called (also called simians or anthropoids), split. Simians seem to have split from a group also ancestral to . Today’s prosimians include , , , and . During the , Africa and Southeast Asia became primate refugia. Tarsiers have , and the live on islands near Southeast Asia. Primate history in the late Eocene and Oligocene is controversial today. The fate of an from primates’ is debated, but they seem at least cousins to ancestors of , if not ancestral to them.

Organisms begin to capture chemical energy.

Those energy and chemistry concepts should make this essay easier to digest.

The was the first mass extinction of organisms that could be seen with the naked human eye. There was an soon before the eon of complex life began, and there may have been mass extinctions of microbes before then, but the evidence is so thin for anything before then that scientists may never know just how many mass extinctions there were. However, bacteria and archaea, those , and those communities do not have the apparent instability of complex life’s food chains, so there may have been few mass extinctions in Precambrian times. Cyanobacteria have not fundamentally changed in billions of years, which means that its mode of living has always worked well enough to ensure its survival. No animals have anything close to such a lengthy pedigree.

Ability to make tree-stored energy available to ecosystems.

Because of the stupendous energy demands of flight, birds not only have the superior air sac system for breathing, but their , the cell’s energy-generation centers, are far more efficient than mammalian mitochondria. Parrots in captivity can , scientists have noted an , and scientists may discover that wild albatrosses live to be 100 or more, when their tagging programs get that old. The may explain bird longevity, as the efficient mitochondria of birds . The theory is controversial and will be for many years, but I think that an engine analogy can help. A bird is a piece of high-performance biological technology, and when operating at peak output it puts all land-bound animals to shame. But a bird’s metabolism is usually in its slack state, only maximized during flight. Simply put, a bird has a great energy capacity that is rarely used to its fullest. It is like a high-performance engine that rarely runs near its . Such engines will last far longer than those regularly running near redline. High-performance technology that usually “loafs” in its slack state and is rarely taxed is expensive and long-lasting. The increased investment in superior technology allows for high performance and long life. High-quality technology is more economical in the long run, if the initial investment can be afforded.

Confers energy advantage to tool user.

Another energy-related activity probably appeared on a large scale during the reign of dinosaurs: . Although territoriality , , , , and today, it is most common among birds and mammals. Territoriality is primarily about preserving an animal’s energy base from competition, and it is usually a behavior oriented toward others of the same species, which would eat the same food resources and mate with the same potential partners. Just as what scientists call , territorial behavior may go all the way back to the . But the social behaviors apparent in dinosaurs probably also meant territorial behavior, and probably on a scale never experienced before on Earth. Even the suspected display function of implies territorial behavior. All are territorial, and human political units such as are little more than ape territoriality writ large, as peoples protect their energy and mating bases. In light of the (with its apotheosis in the peacock, although, as usual, ), and the phenomenon perhaps goes , along with the discovery of dinosaurian mass nesting sites, herd behaviors, and the like, many scientists believe that .