A timeline of human emergence on our planet.
Look around you. We are human & we've overtaken this planet. How did this happen? Let's take a look by highlighting the major natural & manmade events in time which have led to what we are today...
- 14,000,000,000,000 years ago - This Universe. Our universe comes into existence in a massive explosion of energy everywhere, possibly due to the resonations of two 'branes' (parallel universes or dimensions of space). The fabric of our brane unfolds defining the laws of physics as they exist in our universe. The universe cools, and leftover matter is comprised of the lightest elements: hydrogon and helium. Over time, these gases coalesce into the earliest stars where nuclear fusion creates heavier elements (like carbon, key to life on Earth) released as those stars die in violent supernova explosions.
- 4,600,000,000 years ago - Earth. The Sun and orbiting protoplanets in our solar system coalesce from condensed gas, dust, and rocks - likely triggered from the shock of a nearby supernova in our Milky Way galaxy. Our planet formed with relatively active plate-tectonics, which provides an electromagnetic shield from the Sun's atomic bond-breaking radiation (unlike Mars).
- 4,000,000,000 years ago - Abiogenesis, or the emergence of "life" (self-replicating organized matter). The earliest life was most likely RNA-like compounds, which emerged from complex combinations of amino acids in early Earth's organically-rich (methane, ammonia) waters. Extremely active deep sea volcanic vents may have perpetuated and catalyzed the reactions generating these amazing compounds and initiating the process of Darwinian selection.
- 2,000,000,000 years ago - Oxygenic photosynthesis. Cyanobacteria proliferates introducing the first photosynthetic life which will continually produce O2 as a by-product of sequestering carbon from CO2, increasing oxygen concentration in the atmosphere. This atmospheric O2 will support the biochemical energy pathways of respiration in later animal life.
- 1,500,000,000 years ago - Sexual Reproduction. Sexual recombination produces greater variety in the genomes of life, and thus accelerates the process of natural selection which previously relied solely on mutation for variety.
- 1,200,000,000 years ago - Multicellular life. Complexity of life - including plants and animals became possible once life organized on the multicellular level. This allowed cell differentiation into specialized structures like the eye, digestive system, nervous system, and other organs. This eventually led to the Cambrian 'explosion' about 550,000,000 years ago, in which a vast number of animals suddenly appear in the fossil record.
- 200,000,000 years ago - Cerebral cortex in mammals. This folded layer of brain tissue supplemented the reptilian instinctive brain, providing mammals enhanced learning and associative abilities to better adapt to their environment. The cortex grew larger as mammals emerged from nocturnal life and dominated the daytime after the age of dinosaurs.
- 60,000,000 years ago - Primates. These tree-dwelling mammals evolved opposable thumbs (for grasping limbs and vines), forward turned eyes (for depth perception), and a larger cortex (for adapting to more complex social and natural environment).
- 6,000,000 years ago - Bipedalism. Some primates took to the savannah, possibly in search of new food due to receding jungle. Bipedal skills became an adaptation for seeing over tall grasses, and carrying offspring and perhaps sticks for protection from predators.
- 5,000,000 years ago - Symbolic communication (vocalizations, gestures). The first primates (australopithecines) who adapted to the savannah had their hands freed for other purposes. Cooperation and communication became useful in these new, open environments and simple communication and gestures became instictively advantageous. (Chimpanzees have already been proven to have the capacity to learn sign language)
- 2,000,000 years ago - Primitive language, tools, & cranial expansion. Basic communication and cognitive abilities exist with the appearance of the genus Homo (Homo habilus, then Homo erectus) . Fire and hunting are new skills of this species, and simple language undoubtedly helped for cooperative hunting and social interaction. Homo will continually evolve larger craniums over the next two million years.
- 100,000 years ago - Modern language & cognitive abilities. Syntax structures (supported by evolution of Broca's area of the brain) have co-evolved with improved cognitive abilities to process information passed via language by Homo sapiens sapiens. The result is this hunter-gatherer species with cranial capacity twice that of H. erectus, and increased technological and cultural complexity.
- 10,000 years ago - Agriculture & civilization. Mastery of controlled agriculture allows people to support larger populations in permanent settlements. This allows for specialization of skills and trade, spurring more complex economic and government systems.
- 600 years ago - Printing press. This technology started the original information age, as the populous became literate and able to bulid upon the knowledge of others. This initiated a new age in religious and scientific thought.
- 200 years ago - Combustion, mechanics, and industrialization. The invention of engines enabled new powerful and productive tools for manufacturing, agriculture, and transportation. This revolutionized the scale of economic structures and businesses, as well as social structures. War would have airplanes. Cities would have automobiles.
- 100 years ago - Electro-magnetic technology. Applications of this science included electricity, light, and communications (telegram, telephone, radio, and television). This technology changed lifestyles: powering new machines in homes, allowing long-distance communication, and opening up new channels for media and entertainment.
- Present day - Computing & Information networking. Data processing and information access grew exponentially with the creation of personal computer networking and the internet. Process efficiencies would be gained and businesses would become more global. Media, business, and education will continue to be transformed as the Internet integrates into our lives.