The Reign of the Prokaryotes

Here we pick up from Saturday, with the formation of the planets in our solar system and the continents on our planet, Earth. Most of the junk flying around in space had been gobbled up by the Sun, Jupiter, and the rest of the continents. The Earth finally was freed from a constant bombardment of comets and good-sized asteroids. Damaging asteroid strikes did not disappear; they just became much less frequent.

Volcanoes erupted regularly. Between those violent crashes and the volcanoes, the earth’s boiling hot surface included an atmosphere of methane, steam, hydrogen sulfide (the rotten egg smell), and carbon dioxide, in addition to nitrogen and carbon dioxide. No oxygen, though! The earth finally cooled a little, turning the steam into water. Rain poured down for a long time, filling the oceans.

Around four billion years ago, conditions were cruel. The atmosphere and the oceans were a chemical soup. The oceans were green and acidic, the skies orange with high levels of methane, ammonia and carbon dioxide. A complete list of all the ingredients of both the ocean and the atmosphere are not known for certain, but any living plant or animal of today would immediately die if placed in that environment.

Despite these horrific conditions, life appeared. Out of that fiery, dense Big Bang explosion comes the itty-bitty little particles out of which you, your parents, the ground you walk on, the Moon, the stars – everything! – is made. Little bits of that stuff got together just right and out came the first DNA.

Life begins. In the water. Life’s first DNA. That DNA, though, was NOT simple.

Well-preserved bacteria from the era 3.6 to 3.2 billion years ago was found in Western Australia. General agreement for life’s beginning is 3.7 to 3.8 billion years ago.

What arrived was the earth’s simplest form of life. But what is life?

  • A simple explanation: on one hand are living things, plants and animals; on the other hand, inorganic matter.
  • A more precise definition: Living things take in food, grow, and have wastes; they reproduce; and have DNA.

Those first living organisms were single celled. Biology calls them prokaryotic; “bacteria” is easier to remember.

Here is an introduction to that first life form, the prokaryotes. Each organism was surrounded by a thin membrane. Inside the membrane, nutrients moved around, messages were sent, and a variety of other complex tasks carried out. The instructions for all this action were in the DNA. The DNA directions included how to do those things—move, use food for energy, eliminate waste, and reproduce.

Those first living cells were tiny, tiny, tiny. A piece of paper is about one millimeter thick. Those first cells were 1/1000 of a millimeter! Two examples of prokaryotic organisms today are bacteria and green algae.

Those tiny organisms stored essential genetic information coiled up inside. To create this two-for-one step called reproduction, the cell first had to grow to twice its own size. Then it split into two, creating a matched copy of the original. The process was not really that simple but that is an outline.

Reproduction required no external help. The cell was on its own to grow-split-grow-split- … and on and on. Do not scoff at these prokaryotic cells. They are by far Earth’s most consistently successful organism. The reign of the prokaryotes begins and continues for more than two billion years.

Here is a timeline of the beginning of the story from Big Bang to you.

big bang to you

These little bacteria cells had a little tail; they could move about in the water. Today, they exist in plants and animals as well as in the atmosphere. In your body, they help digest food. They also cause you sickness.

The enquiring mind is saying, “How does science know all this stuff? Do they just make it up?” A complete answer would take a book. Next week, a brief explanation!

Next post: How does science know all this stuff?

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The Big Bang: Energy, meet Matter

How did we get here?

Maria, played by Julie Andrews in the movie The Sound of Music, provided this advice: “Let’s start from the very beginning. That’s a very good place to start.” OK. In the very beginning, there was nothing.

Nil. Zip. Nothing.

Time? Nil. Space? None. Matter? Zero. Energy? Forget it.

The situation changed dramatically 13,700,000,000 years ago. Time and space and energy and matter began. Thirteen point seven billion years ago. That’s even longer than a 15-inning baseball game.

The Big Bang happened – a big, big, BIG bang.  From nil, zip, nothing to all of the mass and energy now still in the Universe. Matter and energy hurled in every direction. The time clock started ticking.   Einstein put mass on one side and energy on the other of his famous equation E = mc2. In that equation, “c” means “speed light travels.” The speedometers in all that flying stuff read “c.”

All the mass and energy that exist in the Universe today came from that one Big Bang. No new energy has been created. No energy has been lost.

Energy flying in every direction. Think of a fireworks display. A rocket flies up high then explodes. Pretty white bright lines shoot in a straight in every direction. Crowd cheers. Picture those Big Bang speed-of-light lines shooting in every direction.

matterNewton’s first law says a body in motion stays in motion unless some external force gets in the way. According to that rule, the matter should have just kept going – forever – since no friction existed. That would have led to a flat and featureless Universe.   No stars, no planets, no rivers and mountains, no me, no you, and not a single McDonald’s yellow arch.

So, is that the end of the story?

Dumb question because we ARE alive. That fast-moving stuff flying in every direction contained a surprising hidden something-or-other. That was the external force. The external force caused matter to be attracted to other matter. By that something-or-other force.

Stuff happened. Most of us older people think that electron, proton, and neutron are the smallest particles. Wrong. After Big Bang, that stuff flying through space had fancy new names. Whatever the names, they were banging into each other. After a while, they stuck together and BECAME electrons, protons and neutrons. Then atoms, made from electrons, neutrons and protons, began appearing. First was hydrogen, the simplest atom.

Back to that unexplained force.

Next post: Gravitational attraction at work