The Biggest Events in the Journey of Life on Earth
What, who, where, when, why, and their importance
I recently summarized what I see as the biggest events in the human journey. This will be what I see as the biggest events in the journey of life on Earth, and going back a little earlier.
What: Universe
Event: The beginning, the story since then, and where it may be heading
When: It began 13.6 billion years ago
Why: God only knows
Importance: It brought our physical universe into existence
Discussion: At age 16, I began having paranormal experiences. Some were spectacular, and I know that materialist theories of consciousness are false. Those experiences ruined me as a mainstream scientist before my career began. But I resumed my scientific studies after my life-ruining adventures in the energy business, which even I sometimes have a hard time believing happened.
A close friend was given a demonstration of technologies that would upend orthodox physics if they were publicly available. So I know that orthodox theories fall woefully short of describing our reality. According to orthodox cosmology, in which our universe was born with a Big Bang and is still expanding (although there are still dissident views in orthodoxy to that view), everything in our universe is comprised of energy, but the greatest scientists admitted that we do not know what energy is or where it came from. The most basic questions remain unanswered. My studies of near-death experiences make it clear that time and space are features of physical reality that don’t exist in other dimensions like they do here. There is a great deal of scientific investigation of these issues, which the defenders of orthodoxy either ignore or attempt to invalidate with pedestrian and irrational exercises, if not fraudulent ones.
One of my favorite channeled sources stated that the Big Bang and the idea of an expanding and collapsing universe have a certain validity, as our universe vacillates between matter and antimatter states, and that the expansion and collapse of our universe has happened more times than there are stars in our universe, which our puny brains cannot really comprehend.
With those limitations acknowledged, this post will be more of a tour of the orthodox theories and evidence of the journey of life on Earth. With all of these events, even in orthodoxy there is dissent and alternative hypotheses, and I am generally presenting what I believe to be the leading versions of events.
The leading theory is that the visible universe is almost completely comprised of its simplest element, hydrogen, and enough hydrogen and its attendant gravity is what makes stars. I’ll leave dark matter and dark energy aside for now. They have never been observed, and even in orthodox circles they are suspected to be fudges to preserve Einstein’s equations, like a phantom planet was proposed to preserve Newton’s equations.
All elements other than the simplest ones (hydrogen, helium, and a little lithium) were created either in the fusion processes of stars or collisions of stars and their remnants. For instance, iron is the heaviest element that our Sun will create in its lifetime. Earth’s gold and uranium, for instance, are thought to have been born in those star-sized collisions.
What: Sun
Event: A star is born
When: 4.6 billion years ago
Why: It seems that the Sun formed from the detritus of previous stars and primordial hydrogen, triggered by a local supernova explosion
Importance: It made our solar system
Discussion: The leading theory is that a nearby supernova (or multiple ones) created the disturbance that led to the collapse of a molecular cloud, which is how our Sun formed. In that cloud were also heavier elements from former stars and star collisions, which is what our solar system is comprised of. The Sun has been slowly brightening since its formation, and will be in its main sequence for billions more years before it becomes a red giant and then a white dwarf.
What: Earth
Event: The creation of the home for all life that we know of
When: 4.5 billion years ago
Why: Formed from the accretion disk that made the Sun
Importance: The ground that we stand on
Discussion: Earth is thought to have formed less than 100 million years after the Sun did, from the spiral of stardust of the accretion disk. Earth had the good fortune of forming in what is called the habitable zone, in which Earth retained its water and atmosphere. Venus likely never had standing water, and its atmosphere is almost all carbon-dioxide at 100 times the pressure of Earth’s. Mars had water and an atmosphere, but it was largely lost to space billions of years ago. Earth is the unique planet in our solar system that had the right conditions for life as we know it to form. Earth will be able to host life for another billion years or so, before carbon starvation and the brightening Sun ends the game.
What: Moon
Event: An awesome collision
When: 4.5 billion years ago
Why: The early solar system was crowded
Importance: Earth’s oceanic tides, for example
Discussion: Today, there are no completely satisfying theories on how the Moon formed, but the general idea is that a Mars-sized planet collided with Earth about 50 million years into Earth’s life, and the Moon was the result. There is nothing else like the Earth-Moon system in our solar system. The Moon is so large in comparison to Earth that the Earth-Moon system has been called a two-planet system. The Moon may help maintain Earth’s magnetic field, and is responsible for Earth’s tides, which affected the evolution of life on Earth.
What: Life
Event: A miracle
When: Over four billion years ago
Why: Nobody is quite sure
Importance: We would not be here otherwise
Discussion: All hypotheses for the beginning of life on Earth that I have seen have been inspired guesses. Did it begin on volcanic events on the ocean floor, in freshwater environments, or was it seeded here from a Martian meteorite or even by ETs? I like Nick Lane’s work on the idea of “white smoker” volcanic events, but scientists will never know for sure. In Lane’s latest book, he ranked energy above reproduction, which makes sense, as life had to exist before it could reproduce. But those were the two main tricks of life: acquire energy and reproduce.
What: Enzymes
Event: Life created proteins that made chemical reactions far easier to achieve
When: Probably one of life’s first inventions, at or near the beginning
Why: Speed up chemical reactions
Importance: Life would have never progressed without it
Discussion: Early on, life evolved to make proteins (from the RNA blueprint – DNA came later) that made chemical reactions happen faster, by up to billions of times. We call them enzymes. Without that immense energetic boost, life would have never progressed much, if at all.
What: Photosynthesis
Event: Life captured light
When: Maybe 3.4 billion years ago
Why: Life sought a new energy source
Importance: Life would be a very minor curiosity, of some microbes eking by, if not for photosynthesis
Discussion: The earliest life took advantage of the energy in chemical bonds (called chemosynthesis), but after hundreds of millions of years, some life learned to capture light. It may have originally been infrared light near volcanic vents on the ocean floor, but eventually sunlight was captured. Photosynthesis has been the primary energy source for Earth’s life ever since. This is an event that is considered to have happened one time with one organism, and all photosynthesizers are descended from that organism.
What: Oxygen
Event: One bacterium evolved to split water to get its electrons for photosynthesis
When: As long as 3.5 billion years ago
Why: Electrons are not easy to obtain
Importance: It saved Earth’s ocean from being blasted into space, and thus saved all life on Earth
Discussion: This is another event that is considered to have happened one time with one organism. An enzyme was repurposed to split water to get its electron to power photosynthesis. It was the beginning of oxygenating Earth’s surface. Oxygen is the second-most electron greedy of all elements, and taking an electron from water was no easy trick. The waste byproduct of that new process was oxygen gas. That gas not only began oxidizing Earth’s surface (including forming most of the iron deposits that are mined today), but life also learned to use oxygen in respiration, which supercharged it and led to the rise of complex life. Another outcome was that that liberated oxygen formed the ozone layer that protects Earth’s surface from ultraviolet light, which is very damaging to life’s molecules. That atmospheric oxygen also bonded with the hydrogen that was making its way to space, which made water again and largely stopped the process of the Sun’s blasting Earth’s ocean into space. Mars likely lost its ocean that way, and we all have to thank that lone bacterium for learning that trick. Earth is the only place in the known universe with so much free oxygen.
What: Mitochondria
Event: An Archaean and a bacterium formed a partnership
When: Likely between 2.1 and 1.6 billion years ago
Why: It was likely initially an act of either predation or parasitism, but it turned into symbiosis
Importance: It was perhaps the key to the rise of complex life
Discussion: There is plenty of debate on just how complex cells came into being, but a key event, and maybe the key event, was when a bacterium came to live inside of an Archaean. It became the first mitochondrion. Once again, this is an event that is considered to have happened one time with one organism. The first mitochondria may have respired with hydrogen, but mitochondria were eventually adapted to use oxygen, which was a supercharging event, without which complex life might not have arisen at all. About 10% of the human body by weight is mitochondria. This was generally the last step in the evolution of life so that, pound-for-pound, complex life uses energy 100,000 times as fast as the Sun produces it. There is nothing else like it in the known universe.
What: Chloroplasts
Event: An oxygenating photosynthetic bacterium formed a symbiosis with early complex life.
When: Likely between 1.6 billion years ago and 600 million years ago.
Why: A likely predation event that turned into a symbiosis
Importance: It made plants possible
Discussion: Yet again, this is an event that is considered to have happened one time with one organism. That cyanobacterium that came to live in a complex cell is what led to plants. For land animals like me, its importance cannot be overstated. Plants are the basis for nearly all land-based complex life. Plants capture the energy that powers land-based ecosystems.
What: Animals
Event: Complex cells entered into a symbiosis that formed large organisms that relied on photosynthesizers for their energy
When: 760 to 665 million years ago, but maybe even a billion years ago
Why: Another symbiotic event
Importance: I am an animal
Discussion: As this list may make clear, symbiosis has often been a key way that evolution has led to new lifeforms. The earliest animals were sponges and other immobile creatures, and stationary animals generally dominated for many millions of years, but they largely went extinct, and relatively few animals are stationary today (it went from 80/20 to 20/80).
What: Ecosystems
Event: The Cambrian Explosion
When: Beginning 541 million years ago
Why: There are several schools of thought on that
Importance: The first “modern” ecosystem, which led to increasing diversity and nearly all animal phyla were established in the Cambrian
Discussion: The Cambrian Explosion is considered the most important event in the history of complex life. Why it happened has been one of paleology’s more enduring debates. The rise in oxygen levels has long been suspected to be a trigger for it, but the history of oxygen levels themselves is one of the liveliest controversies in paleology that I have seen. What nobody debates is the eonic significance of it. That event began what has been called the Phanerozoic, which is the eon of complex life that we still live in. One of the most fascinating related topics is the Cambrian Period’s precursor, the recently named Ediacaran. The Ediacaran’s creatures have been long debated as early animals, plants, or neither. They weren’t what would be generally recognized as animals today, but the leading idea is that they were early animals.
The Cambrian was the first time that recognizable ecosystems appeared, with what we now call food chains with apex predators, even though in the Cambrian, 80% of all animals were immobile. All but one of the recognized phyla today originated in the Cambrian, including vertebrates, which humans belong to. The Cambrian became the template for all that followed with complex life.
What: Extinctions
Event: Species extinctions, which go back to the earliest life; in the eon of complex life, there have been many mass extinctions
When: Probably began over four billion years ago and life on Earth will end with the last extinction
Why: Always primarily an energy issue, with many proximate causes
Importance: An essential feature of evolution
Discussion: More than 99.9% of all species that ever lived are extinct. Extinction is an essential feature of evolution. The first species on Earth went extinct, and a fossil record of them will likely never be found. When Earth’s atmosphere became oxygenated, there may have been the first event that is called a mass extinction, when many or most species go extinct at the same time. I have listed the most significant ones here. Today’s humans are the only surviving species of the line that split from apes several million years ago, and our turn will come.
What: Land
Event: Life moved to land from the ocean
When: Maybe began 2.4 billion years ago
Why: It was a frontier to settle
Importance: Life took new directions on land
Discussion: Scientists think that there is evidence of life on land over two billion years ago. None of it would have been too impressive to modern eyes until plants began the migration to land. It could have begun 600 million years ago, but the first plant fossils on land are dated to about 470 million years ago. Plants competed for sunlight and other benefits, and about 40 million years later, along came animals, mainly arthropods at first, which also dominated the Cambrian. For the next 300 million years or so, plants defended against animals, with bark, thorns, toxins, and the like. After 40 million years or so of arthropod tenure on land, fish began to invade. Push-pull dynamics were likely involved, as the lobe-finned fish that migrated to land were losers to ray-finned fish in the ocean. What began as an act of survival became an opportunity. The big evolutionary innovations often came from the fringes, where the risk-reward ratio was high for marginal species that did not have much to lose. Those innovations often led to dominance for the inventors.
Land-based ecosystems were radically different from aquatic ones, partly due to the adaptations needed to survive on land, and most phyla have not made the transition. Animals dominate the ocean, and cyanobacteria form the oceanic food-chain’s base. Plants comprise 82% of the world’s biomass today, and it was nearly 90% before the human Domestication Revolution wiped out half of plant biomass. Land made that all possible.
What: Ice
Event: Earth has experienced several ice ages
When: Beginning more than two billion years ago to today
Why: Primarily declining greenhouse gases and continental configurations
Importance: Dramatic environmental changes and elevated extinctions
Discussion: Ice ages are times of environmental tumult and elevated extinctions. Earth’s first ice age began about 2.4 billion years ago, and the leading hypothesis is that the oxygenation of Earth’s atmosphere (see above) removed methane from the primordial atmosphere, and methane is a far more potent greenhouse gas than carbon dioxide is. That same oxygenation is also thought to have driven many microbial species to extinction, as oxygen was highly toxic to them. That is hypothesized as Earth’s first mass extinction. That ice age lasted for hundreds of millions of years, and the next one that began about 720 million years ago and ended about 635 million years ago (when I wrote my essay the included it in 2014, it was thought to have begun 850 million years ago, to show how flimsy those old dates can be). That was the notorious “snowball Earth” ice age. Complex life began its rise after the ice age ended, and it was likely no coincidence. Low levels of greenhouse gases are implicated in all of Earth’s ice ages, through either lower volcanism (which introduces carbon to the carbon cycle) or higher deposition (which removes carbon from the carbon cycle). Also, the continental configurations seem relevant. In the eon of complex life there have been three ice ages, including the one that we are in today, and elevated extinctions accompany the process. The end of the previous ice age coincided with the greatest extinction event in the eon of complex life. Humans may have ended this ice age by burning up Earth’s hydrocarbon deposits to power humanity’s industrial Epoch. We will see about those extinctions.
What: Dinosaurs
Event: The arrival of dinosaurs and their archosaur cousins and their domination of Earth (land, water, and air)
When: Dinosaurs appeared about 233-to-243 million years ago, dominated after 201 million years ago, and a bolide drove them to extinction 66 million years ago
Why: Likely their ability to rapidly grow to huge sizes
Importance: A key evolutionary period in the eon of complex life
Discussion: Rock stars among children, dinosaurs are among the most fascinating life forms in Earth’s history. The ancestors of mammals dominated during the Permian Period, while the ancestors of dinosaurs were fringe dwellers. But after the greatest extinction event in the eon of complex life, the ancestors of dinosaurs soon rose to prominence, while what became mammals became fringe dwellers. Dinosaurs appeared between 243 and 233 million years ago, about 10 million years before mammals did. Early dinosaurs vied with other reptilians while rat-sized mammals lived on the fringes, in burrows which they left at night to feed. After the Triassic Extinction, which was one of the major ones, dinosaurs and their archosaur cousins dominated land, sea, and air for the next 135 million years, until a bolide event ended it all. The only dinosaurs to survive were beaked birds, probably because they were seed eaters and enough seeds survived for some of them to survive that cataclysm.
Why dinosaurs rose to prominence has been one of the many controversies in paleology, but it likely was related to how fast they grew to sizes never seen before or since, their speed, which is thought to be related to their metabolism, temperature regulation, and breathing behavior, and they survived a mass extinction at 230 million years ago, which wiped out a proto-mammalian line. The ground shook when those giants roamed the land. There were three basic types of dinosaurs: browsers like stegosaurs and triceratops, the immense sauropods, and the bipedal theropods that often preyed on them, although birds are theropods.
Some dinosaurs had relatively large brains so were likely highly intelligent (many bird species are), and some even had hands. If not for the bolide event, maybe Earth would host spacefaring dinosaurs today instead of spacefaring mammals.
What: Flowers
Event: Plants evolved to feed animals instead of defend against them
When: Maybe began 190 million years ago, but certainly by 125 million years ago
Why: Feeding animals lowered the reproductive costs of plants
Importance: The greatest symbiosis of plant and animal ever, which had dramatic evolutionary impacts
Discussion: For hundreds of millions of years, plants defended against animals, with bark, thorns, toxins, and the like. Plant reproduction was also very costly. A fir tree could produce a million cones for every one that lived to become a large tree, and vast amounts of pollen were released, to fertilize neighboring members of the species. Between 190 million and 125 million years ago (I used 160 million in my original essay), flowering plants appeared, and they turned plant strategies on their head. Instead of defending against animals, they fed them, as a way to not only reduce their reproductive costs, but animals that ate pollen, nectar, and fruit were less likely to eat the vital plant parts. It is the greatest symbiosis between plant and animal ever. Flowering plants soon became a hit with dinosaurs and other animals. Flowering plants also grew and matured faster than animal-defending plants did, and they dominate Earth’s warm climates today.
What: Mammals
Event: Mammals arrived on the evolutionary scene, with markedly different biology and behaviors from their reptilian cousins
When: Mammals evolved about 225 million years ago
Why: The arrival of mammals reflected different evolutionary trends, such as in their teeth, jaws, brains, fur, and how they fed their infants
Importance: After that bolide event ended the reign of dinosaurs, mammals have dominated Earth for the past 66 million years
Discussion: From their arrival on the evolutionary scene 225 million years ago to the bolide event of 66 million years ago, mammals were fringe-dwellers, trying to survive in a world dominated by dinosaurs. Early mammals were about the size of rats and never got bigger than raccoons before that bolide event. They generally lived in burrows and were nocturnal feeders, as dinosaurs dominated the daylight hours.
From the beginning, mammals were relatively brainy, thought to be to support the keen senses that mammals need to survive. They developed teeth that were only replaced once, a different jaw that allowed for larger brains, fur, most of them developed live birth instead of laying eggs, and they provided milk to their infants. It was a very different direction in evolution, which might have gone nowhere if not for that bolide. But that bolide did hit, and those fringe-dwelling mammals survived when dinosaurs, other than beaked birds, did not. As the biomes recovered from that cataclysm, mammals wasted no time in rising to dominance and often becoming huge, if not nearly so large as dinosaurs. Nearly all mammals today had recognizable ancestors by 50 million years ago. Just then, however, the past 200 million years of a warm Earth began to end, and with a few blips, Earth steadily cooled to today’s ice age. And then one mammal rose to dominance and has wiped out nearly all mammals that it did not domesticate, as well as half of Earth’s plant biomass, most coral ecosystems, and that species has taken Earth to the brink of an extinction event that might exceed all others. That is quite a feat. Were mammals a “good” evolutionary idea? Is “intelligence” an evolutionary dead-end?
What: Grasslands
Event: Grasses came to prominence in a cooling, drying Earth
When: Grasses evolved at least 100 million years ago, and by five million years ago, all continents other than Antarctica had extensive grasslands
Why: A new evolutionary strategy for flowering plants, which became highly successful as Earth cooled
Importance: Not as dramatic as the evolution of flowering plants, but grasses led to new biomes, with profound evolutionary consequences
Discussion: People are generally surprised to learn that grasses are fairly new on the evolutionary scene, and especially that the rise of grasslands is quite recent. It was not until about five million years ago that grasslands became dominant biomes. The Earth has been cooling and drying for 50 million years because of declining carbon dioxide levels, right-wing protestations notwithstanding. Another piece of evidence for that is that somewhere around 30 million years ago, plants invented a new process of photosynthesis, which conserves carbon dioxide and water. Grasses are the most common plants that use that new form of photosynthesis, called C4.
As forests and woodlands gave way to grasslands, browsers of trees evolved to become grazers of grass. Eventually, Earth hosted the spectacle of speedy predators that chased fleet-footed grazers. That biome was new in the journey of life on Earth. It was eventually dominated by bipedal apes with weaponry, which became the most successful predators in Earth’s history, and they began driving large animals to extinction, especially those of the grasslands.
What: Humans
Event: Bipedal apes flourished and conquered Earth
When: The conquest may have begun with the making of stone tools
Why: A likely series of positive feedbacks between growing brains, energy acquisition, and increasingly sophisticated tools
Importance: No other species ever dominated Earth like humanity has
Discussion: I made a recent post on the biggest events in the human journey, so there is no need to recapitulate them, and I have sketched the evolutionary path of primates that led to bipedal apes. Humans are the most successful predators in Earth’s history, due to their unprecedented intelligence and tools. Nothing on Earth could compete with that, and the most advanced tool users drove all other human species to extinction, leaving Homo sapiens alone on that evolutionary branch. But humans are at the stage where they might become too “successful” and make Earth uninhabitable. My life’s work has largely about avoiding that outcome and restoring Earth to something like paradise, as humanity will then live in an Epoch of unprecedented abundance.
As I finished that human-journey post with, time is short, and I have a plan.