Enter Oxygen

On Wednesday, we asked: how does science know all this stuff? The answer: rocks.

Rocks store old information. First, a rock holding such critical information must be found. Once found, then the rock that held that information must be dated. In the rock are elements that have a “nuclear decay” — they shoot off a little energy which basically creates a new element. Time is measured by the amount of the new element in the old rock. The equipment used is pretty sensitive.

Logic also gets involved. If the rock fossils are all single celled, then that rock existed before multicellular life appeared. The single cells are at the lower level; multi-cells one layer up.   In a big, broken stone or a cliff with many layers, clearly each new layer appeared after the one below. By piecing all this information together, geologists can make reasonably accurate estimates for timing of ancient events.

When scientists asked, “What happened?” and “What are the steps that made it happen?” the response usually falls back on Charles Darwin’s natural selection interpretation.   Most people have heard that term “evolution”; unfortunately, however, a large percentage do not really understand the details. All at once, first life was under attack. The next step (which saves the prokaryotes) in the story is an example of now Darwin’s approach works.

Those first little bacteria were flourishing, thriving on an oxygen-free environment. They were having a jolly time covering the earth. But then — the plot thickens — they came under attack.

What attacked them? Oxygen. Photosynthesis arrived near the middle of the Reign of the Prokaryotes. Bacteria capable of photosynthesis were ingesting carbon dioxide and spewing out oxygen. Soon the atmosphere had a lot of oxygen. To the existing prokaryotes, oxygen was poison; they were dying off in droves. If they all die, well, this story ends and there would be no you or me.

Why didn’t then all die? Darwinian interpretation involves a two-step process.

Those bacteria reproduce by splitting in two. After the split, both parts have exactly the same DNA structure. But random accidents happen; sometimes one of the cells does NOT have exactly the same DNA structure. That oddball cell is called a mutation. So start with the first step: random mutation.

The second step is called natural selection. Change is triggered by those reproductive mistakes. The mutation fights to survive – to find food, to reproduce. Most mutations die off; after all, they happened by chance. But along comes a mutation that CAN survive even if oxygen is in the air. That mutation flourishes, reproduces like crazy, and starts dominating. A change has occurred in that bacteria cell’s DNA. Children who come from this somewhat changed DNA are also better-able to handle oxygen. That new, DNA-altered bacteria thrived. The “random” part is the mutation. The “natural selection” here is that nature selected the bacteria that reproduced and thrived most successfully.

Another question: Did this change occur because of just one mutation in one cell? Many believe that other bacteria, under the same strained conditions, could also have created mutations that could thrive on oxygen and be successful. Perhaps there were hundreds of such mutations and, probably, they were not all exactly the same. They could all a little different BUT all can handle living in oxygen. Over time, they will converge to one big happy family, all of whom have a DNA structure altered in a manner allowing them to thrive on oxygen.

A lot of time had passed, but the Reign of the Prokaryote finally came to an end. In their nearly two billion year dominance, evidence shows that all over the Earth, where there was water, some form of bacteria was growing. Sometimes it made its way onto land.

Soon more complex life will join them on Earth. That more complex cell only formed because two groups of bacteria species joined together, merging permanently.

The beginning steps – life beginning, the new life form flourishing and then a more complex form appears – happened in an environment capable of making dramatic changes. Like it or not, each new life form had to be in harmony with the environment around it. Next week, we’ll look at a sort of short description of how these dramatic environmental shifts happen.

Next post: A look at the dramatic environmental shifts that allowed for a new form of life!

Previous post: The Reign of the Prokaryotes

Raising Student Performance with Foundation for Excellence

Foundation for Excellence is a detailed, objectives-driven program designed to raise student performance every year.

In addition to annual performance growth, Foundation For Excellence includes:

  • An annual validity check linked to commonly known academic performance measures;
  • A connection between academic performance to a career-directed secondary school experience, based on the student’s personal likes and dislikes, beginning at age 12.
  • A long-range viewpoint, beginning at Grade 2 and carrying through post-secondary school education.

First, let’s take a look at annual performance growth.

In most K-8 schools, at the end of a unit (e.g. Long Division), after quizzes and homework, a unit test appears. The time devoted to this unit is limited by the teacher’s year-long schedule.

At the end of that group instruction, some students have total mastery, some have just a little error baggage, and some leave with a lot, as the following graph shows:

Usual performance distribution after new unit is taught.

Usual performance distribution after new unit is taught.

That error baggage may (or may not) be corrected by another teacher.

The Foundation for Excellence model also begins with timed group instruction, but includes no exam at the end of the unit.

Instead, each student begins working through diagnostics—shorts list of items designed to identify ANY and ALL of that student’s error baggage.

The student works alone at his or her own rate. When diagnostics have been completed, the mastery test is given.

As the following graph shows, no student leaves this unit until he or she can show a 90% mastery of the content:

Same unit, performance distribution with Foundation for Excellence.

Same unit, performance distribution with Foundation for Excellence.

Next post (Thursday, March 5): How does this lead to annual student performance growth?

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?

Previous post: Gravitational attraction at work

Gravitational Attraction at Work

Take a pencil off the desk. Hold it above the desk. Drop it. The pencil clunks on the desk just like you knew it would. But why?

It falls because the pencil has mass. The Earth has a lot more mass. A force starting at the center of the huge Earth mass is attracted to the mass of that little pencil. The two objects, pencil and earth’s center, are about 4000 miles apart but still close enough to cause the earth to grab that pencil and hug it. Call it what you want — the force of gravity or gravitational attraction – but here is a good way to remember: Matter likes matter. Every piece of matter in the Universe likes every other piece of matter in the Universe. Maybe it should be called the “Hey, let’s get together!” syndrome.

Newton called “liking each other” gravitational attraction, a much more boring name. His equation said the bigger the two masses were and the closer together they got, the more would be the force to pull them together.

Gravitational attraction at work: For about a half billion years after Big Bang, the sky was filled with a sort of dense fog but was also very, very bright. Then all went dark; light returning later from an exploding star.

Around seven billion years later, a giant cloud of matter formed the Milky Way. Our sun was there, one of the new folks on the block; its tremendous gravity had convinced a whole lot of other matter to tag along.. Out of that came our planet, third from the Sun with the moon (about the size of the planet Mercury) flying around it.

Picture it. Our sun was in the Milky Way but all matter was still trying to zoom away from the Big Bang explosion site. Our planet has been attracted to this huge chunk of matter (our sun.) Gravitational attraction existed; yet everything – Sun and planet surrounding it – still had the momentum to fly in a straight line away from the Big Bang explosion site.

But the Sun has a mass much, much larger than ours. The force of attraction between our earth and that much-bigger sun was strong. A real conundrum!   Momentum wanted the earth to keep going in a straight line. But gravitational attraction wanted to bring earth down and to crash into the Sun. Gravity and momentum are in a fight to the death!

Eureka! A tie! Earth’s inertia to fly off further into space was balanced by the gravitational attraction between Earth’s mass and the Sun’s mass. And, since Newton’s rule that some external force is needed change things, the tie will continue. The same type of combination of forces keeps the Moon in a pretty constant orbit around us.

The Earth’s hot center is metallic, the source of Earth’s magnetic field.   The magnetic field is what pulls your compass needle to N (north), but more importantly, that magnetic field shields Earth from those death rays sent down by the Sun. A strong burst from the Sun, though, can send enough through to provide us with those magnificent Northern Lights.

Our planet’s surface was dry at first but water was in the atmosphere. As our earth cooled, the water vapor in the atmosphere became water; then came the oceans. Many scientists feel a good deal of our water came from colliding comets made of frozen water. Wherever the water came from, for a long time the Earth was just one long, uninterrupted ocean of water.

Volcanoes interrupted. Sometimes that collection of lava got high enough to peak over the top of the constant ocean. Volcanoes, however, were not the only source of land. What else could there be? Colliding candy bars.

Imagine taking a thin chocolate candy bar and, holding both ends. Apply a little pressure. The bar splits into a bunch of funny-shaped flat surfaces. Since our Earth is a sphere, how could those funny-shaped flat plates cover the earth? The only way it worked was to have gaps between them.

As the earth’s molten surface cooled, the hard crust—now eight of them. Think of a whole bunch of broken chocolate pieces pressed all around a round scoop of ice cream. Those eight plates covering the earth float on top of the boiling molten center of the earth, protecting what is above from that intense heat.

“Float.” Those plates slowly floated around, large and small, banging into one another, parting company, crashed again (sometimes hard enough to lift up today’s mountains), and kept moving – as they still do today! (Plate-drivers must have been texting while they drove.) The very ground on which you live has been all over the globe – below the equator at times, close to the South Pole at times and really, really cold, near the equator and really hot, and finally setting here at the mid-latitudes of the Northern Hemisphere.   The continents began to take their places.

Next post: The Reign of the Prokaryotes

Previous post: The Big Bang: Energy, Meet Matter

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