Please consider that astrophysicists do not know the beginning of the universe or the beginning of Being. Scientists prefer to stay within their ability to perceive and measure.
What they perceive they describe as energy and mass. Rocks have mass, and a rock's energy is detectable when its atoms are split. Scientists date rocks by measuring radiation decay (uranium breaking down into lead), and with this they estimate the Earth's age at 4.4 billion years — a challenge to our imagination.
Astronomers have mapped celestial bodies, and they see bodies in space moving away from a center: an explosion at a central point, the "Big Bang". They see it as energy concentrated at extremely high density, cooling as it moves outward and forming subatomic particles and simple atoms. Scientists consider that something unknown is pushing the universe apart, and they call this something "Dark Energy". And they see evidence of a force the call gravity that has brought particles together in the form of stars and galaxies. That is what they see, and they call it the universe without knowing whether there are or have been other universes.
In our solar system, gravity pulls bodies toward the sun. Inertia is the tendency of bodies to move in a more-or-less straight line, and without gravity everything would fly outward. Without inertia everything would crash into the sun. Together these two forces produce orbiting around the sun.
Gravitation formed the Earth as denser matter (iron and nickel) settled toward its center. Rocks settled upward toward the Earth's surface. Gasses settled on the surface and became atmosphere. When the temperature was right, gasses in the atmosphere produced clouds that contained moisture – hydrogen and oxygen. It began to rain, and water began to cover much of the Earth's surface.
From the sun, electro-magnetic radiation of various wave lengths extends to the Earth. One of the wave lengths we see as light. Other wave lengths we measure with instruments: gamma rays, x-rays, microwaves, ultra-violet light, radio waves and more.
Astrophysicists estimate that the sun has made 23 revolutions around our galaxy since the sun and earth were formed. One revolution of the sun around our galaxy is said to take 200 million years.
On the earth's surface, molecules (two or more atoms) bounced off each other and bonded. Within the chaos a bit of regularity had begun. Molecular interactions produced single cell organisms: bacteria, archaea, protozoa, algae, and fungi. According to the Encyclopedia Britannica, bacteria developed between 419.2 to 358.9 million years ago. Sunlight on single-cell matter released oxygen into the atmosphere — photosynthesis. With more mixing and chemical bonding more order formed: multicellular organisms appeared. Life had begun, and seeds. Part of the cellular structures were deoxyribonucleic and ribonucleic acids (DNA and RNA) carrying in seeds what we call genetic instructions for development of these organisms. Only those organisms thrived that were constructed in a way that made its survival possible. Biological evolution had begun.
Plant life arose after fungi had been putting nitrogen and oxygen into soil. Depending on environmental circumstances, species of trees evolved from ferns and other plant life. In addition to plant life there were insects and other creatures with a sensory nervous system – systems that served them in seeking moisture, nutrition and escaping danger.
Plant life evolved with characteristics that were allowed by their environment. (Therefore today we have trees with broad leaves in the warmer climates and trees whose leaves fall or are needle-like in the colder climates.
And the evolution of different living things involved sequence. Theoretically, before there were animals there was the plant life on which the animals were to feed, and after there were animals came those insects that lived off sucking blood.
With bacteria change was sequential and continual. Today, we have antibiotics, invented to destroy a bacteria population, but a mutant bacterium that has an immunity to an antibiotic can survive and reproduce a new generation of bacteria that makes the antibiotic ineffective. Of the different kinds of bacteria, what has been described as "fast bacteria" divides every twenty minutes or so.
Some small creatures have genes that program them for death in days. Other creatures are programmed to live for decades if they manage to escape catastrophe. An ability to escape danger allows a species to mutate to a longer life. Small birds can defend themselves by flying away have a normal life of a decade or more. Mice, on the other hand, die of old age in a year or two. In the plant world – also governed by genetics – giant trees have had extraordinary security through their size, and this is matched by a lifespan for some species that span more than 1,000 years.
In addition to lifespan as a characteristic determined by genetics there are behavioral traits that play a role in species survival. Big cats in the wild inherit what we call hunting instincts. Today we see survival of this instinct in domesticated cats when they chase a toy or a bird. And in domesticated dogs we see inheritances from wolves – characteristics that made living in a pack and survival possible. This includes a capacity for empathy and bonding among pack members.
The evolution of living things involves a change in genes and an organism transmitting that change to subsequent generations. Across millions of years a great variety of species has developed – a species defined by its ability to interbreed. And that interbreeding produces births that are less than perfect copies of their parents — a platform for more evolution.
Around 245 million years ago giant lizards appeared that we call dinosaurs. These dinosaurs divided into more than fifty different species that were to be labeled by scientists as the Triassic dinosaurs. (Triassic refers to the Earth's geologic period between roughly 252.17 to 201.3 million years ago.)
During the Jurassic geological period – 199 to 145.5 million years ago – when land was breaking up into separate continents, the Triassic dinosaurs were extinct and a new species of dinosaurs appeared. One was Brachiosaurus. There was also a pigeon-size dinosaur, Epidexipteryx, that had tail feathers. And living between 155 to 150 million years ago was the bird-dinosaur, Archaeopteryx, the size of today's eagles.
Around 115 million years ago a bird-like creature with wings of skin rather than feathers and a wingspan of around 16 feet was in the skies of what today is Brazil. Today it is called a pterosaur.
Among the last of the non-flying dinosaurs was Tyrannosaurus Rex, believed to have lived from approximately 68 to 65 million years ago. It was as much as 43 feet long including tail, and it was 13 feet tall with a running speed of approximately 18 miles per hour. No dinosaurs have been found in a layer of earth dated less than 65 million years ago, giving us a rough date as to when dinosaurs became extinct. (Being as large as a dinosaur had its disadvantages. Small creatures could burrow into the ground to protect themselves and didn't need as much food.)
Something like 17 million years after the great dinosaurs disappeared, changes in a mammalian creature on earth allowed it to become aquatic, and in the sea the mutations continued. Eventually this produced the variety of species that we call whales.
One of the creatures that didn't disappear with the dinosaurs was a small mammal to be classified as a primate. Evolution produced many primate species. Some of them became extinct. And around 7 to 5 million years ago, according to scientists, a species of primate was the common ancestor of today's chimpanzees and today's humans. The Encyclopaedia Britannica states that comparisons of "specific DNA sequences" between humans and the chimpanzee reveal a percentage of genetic identity in the upper nineties.
According to Britannica, research suggests that humans and Neanderthals had a common ancestor between 700,000 and 500,000 years ago and that by 370,000 years ago they had become largely genetically separate. Some interbreeding between Neanderthals and humans is thought to have occurred between 60,000 and 50,000 years ago, leaving a Neanderthal contribution to the DNA of modern humans. And Neanderthals are thought to have become extinct about 40,000 years ago.
CONTINUE READING: Humanity out of Africa
Copyright © 2018 by Frank E. Smitha. All rights reserved.