Symbiosis, is everywhere around us if we know what to look for. Lichens, those scraggly little things that grow on rocks, are half algae half fungi. Fungi and Algae are two very distant families The algae provides the ability to photosynthesize and the fungi provides the physical structure and the ability to gather nourishment from rocks. Neither of the two species that makes up the lichen can exist anymore without the other.
Coral is a creature that forms all the coral reefs in the warm waters of the oceans. Coral is both an animal and an algae. The algae is what gives coral it's colour the greens, reds, and yellows. The animal, called a polyp, is what secretes the calcium carbonate or rock hard body of the coral. If the water stays too warm for too long it kills the algae. If the algae die, the coral dies, because the animal part cannot survive without the energy it gets from the photosynthesizing algae.
The largest structure made from living creatures is the Great Barrier Reef in Australia. This is a series of coral reefs 2600 kilometers long and 344,000 square kilometers. This huge living structure is bleaching out and dying because the algae part of the coral organism cannot tolerate the warmer waters.
Trees are in symbiotic relationships with soil fungi that live on their root tips. The fungi extract minerals and chemicals from the soil and feed them to the tree and the tree is able to feed the fungi with sugars manufactured through photosynthesis in it's leaves.
Termites, which can eat wood, digest the wood with the help of specialized bacteria in their stomachs. Cows and other grass eating herbivores are able to digest the cellulose in grass because of bacteria in their stomachs. Without the bacteria, the cow would not be able to digest the grass. Without the cow, the bacteria wouldn't have access to so much fresh grass,
There are bacteria in our intestines that help us process our waste, making it easier for our intestines to absorb Vitamins B12 and K. Without these vitamins we get blood disorders. When both creatures benefit this is called symbiosis.
There is, in every cell in our body a thing called a mitochondria. Much smaller than a cell, the are about the size of a bacterial cell. The mitochondria take oxygen and sugars and join them to phosphorus creating molecules that store energy. They're like little generators inside your cell. And there can be anywhere from one to a thousand or more of these little mitochondria in each cell, especially in cells that do a lot of work like muscle cells.
In fact, mitochondria are in every type of eukaryotic cell, the type of cell that makes up just about every living thing we know about . But they do not exist in any prokaryotic cells, which is what bacteria are. That means that mitochondria originated when eukaryotic cells originated, 1.2 billion years ago, after oxygen had become 21 % of the atmosphere. Bacteria could live without oxygen, but eukaryotic single celled creatures with their bigger size and more complex structures couldn't have done without the extra energy that oxygen provided.
One of the most interesting things about mitochondria is that they have their own DNA. Not only that, they appear to be one of the few organelles like plastids in plants and algae, that divides by itself.
Microbiologist Lynn Margulis was not the first scientist to suggest that mitochondria and plastids were actually forms of ancient bacteria, but her version was the first to gain acceptance in the biological community. This was largely because when it became technically feasible to analyze the DNA of mitochondria and plastids separately from the cell's nucleus, scientists discovered that the DNA of these organelles was more closely related to the DNA of ancient bacteria then to the DNA in the cell's nucleus.
Something happened 1.2 billion years ago. An oxygen breathing bacteria got swallowed by or invaded a non-oxygen breathing bacteria. Instead of harming each other they benefitted each other. The new cell couldn't survive without the oxygen breathing bacteria so they too were passed on whenever the cell divided. Over time the oxygen breathing bacteria lost some of it's independence, until it too could not survive outside the cell.
All algae, all plants, all animals, all fungi, all single-celled eukaryotes came from this symbiotic combination of bacteria 1.2 billion years ago. And the evidence for this caper is in every one of our cells.
One of the reasons it took so long to accept this theory of cell symbiosis is because this didn't quite fit the Darwinian picture. Natural selection was supposed to be imperceptively gradual and stepwise. But here we have the biggest revolutionary change in biology next to the origin of life, the evolution of eukaryotic cells from procaryotic cells, occurring through the fusion of two or more types of ancient bacteria.
This wasn't a gradual series of changes in the cells' characteristics. This was a relatively sudden jump in the structure and functioning of a cell due to the joining together of two or more distinct species. This fusion may have taken time and many generations to complete and it may have happened more than once, but the time frame was the opposite to the slow gradual time frame that Darwin had suggested.
The evolution of dinosaurs and human beings was child's play compared to the evolution of the eukaryotic cell. And it couldn't have happened without symbiosis.
Monday, November 9, 2009
Saturday, October 31, 2009
Eukaryotic Cells: Size Matters
Every living thing is either a cell or made up of cells. The fact is, every living thing starts life as a single cell. This divides and divides again as the body is constructed cell by cell.
Lewis Thomas in his famous essay “Lives of a Cell said: “ The uniformity of the earth's life, more astonishing than its diversity, is accountable by the high probability that we derived originally from a single cell.”
The cell is the basic building block of biology. It can be all there is to an organism as many creatures are single-celled, including all bacteria. For humans and other multi-celled creatures one cell can be a tiny fraction of our body, yet each and every cell in our bodies carries our entire genetic identity.
The cells of every living thing are unique. They all contain DNA molecules, the molecules of heredity, that are unique to that particular organism and nothing else. That's why my body can detect the cells of other organisms and produce antibodies that mark these alien cells for destruction by my immune system.
It was about a billion years ago I recall, when something very important happened and a new type of cell developed from bacterial cells. This new type of cell we call Eukaryotic.
If you are old enough to remember, at that time there were no plants, no animals, only microscopic critters called bacteria. Lots and lots of bacteria, many different kinds of bacteria: bacteria that ate iron sulphate and produced sulphur and bacteria that ate sulphur and produced hydrogen sulphide, bacteria that produced methane and bacteria that ate methane. And while there was great diversity in the different metabolic processes that bacteria could do there wasn't much diversity in the size and shape of bacteria.
Why would diversity of size and shape matter? Think about what a world of nothing but bacteria would look like... We're talking soup, slime, and ooze, and PU, what a smell. Enough to literally kill you - not a particularly attractive place to raise your kids. And that was what life on Earth was like for maybe three billion years. Until eukaryotic cells came along, that is.
OK, now what does life look like? There's grass, human beings, seaweed, eagles, redwood trees, moss, elephants, sharks and whales. There's microscopic single-celled sea creatures with fantastic glass houses called diatoms, there's turtles and squids and giant clams and periwinkles. Talk about different shapes and sizes and temperments. Better than 60 degrees of slime any day.
Eukaryotic cells, which is what plants, animals, fungi, and diatoms are made of, are bigger and more complex than prokaryotic (bacterial) cells. They have more parts than bacterial cells and much more DNA, 1000 times more. Eukaryotic cells have more membranes that separate and protect all the numerous parts of the cell.
Eukaryotic cells can do more things, they can specialize and link up to other cells forming organs and entire bodies. They have structures and scaffolding that allow the cells to move about like amoeba or link together like bones, skin, nerves and muscles or layers and fibers in a tree. They can secrete shells of calcium carbonates or silicates to surround and protect themselves.
Bacteria just don't have it in themselves to do any of these things. Their masters of the slime universe but what do they do besides consuming and polluting and exchanging genetic calling cards?
Let's not be disrespectful to our elders now. After all it was out of bacteria that the eukaryotic cell evolved. And that's the amazing thing that I'd like you to contemplate, because if we're looking at the “tree of life” then bacteria aren't in the branches and they aren't part of the trunk. They are in the roots.
Charles Darwin conceived of evolution as a tree with successive species as successively smaller branches, as old species went extinct and new species came into being. New species developed by inheriting new characteristics that eventually separated them from the old species.
Darwin saw the mechanism behind the generation of new species as the competitive struggle to survive. But note: the roots of a tree don't compete with each other. They each extract nutrients from the ground and send them into the tree.
Just so, the first eukaryotic cell evolved not from bacterial competition but from bacterial cooperation. That's something that Darwin didn't anticipate. Tune in next week as I describe how this symbiosis came about.
Lewis Thomas in his famous essay “Lives of a Cell said: “ The uniformity of the earth's life, more astonishing than its diversity, is accountable by the high probability that we derived originally from a single cell.”
The cell is the basic building block of biology. It can be all there is to an organism as many creatures are single-celled, including all bacteria. For humans and other multi-celled creatures one cell can be a tiny fraction of our body, yet each and every cell in our bodies carries our entire genetic identity.
The cells of every living thing are unique. They all contain DNA molecules, the molecules of heredity, that are unique to that particular organism and nothing else. That's why my body can detect the cells of other organisms and produce antibodies that mark these alien cells for destruction by my immune system.
It was about a billion years ago I recall, when something very important happened and a new type of cell developed from bacterial cells. This new type of cell we call Eukaryotic.
If you are old enough to remember, at that time there were no plants, no animals, only microscopic critters called bacteria. Lots and lots of bacteria, many different kinds of bacteria: bacteria that ate iron sulphate and produced sulphur and bacteria that ate sulphur and produced hydrogen sulphide, bacteria that produced methane and bacteria that ate methane. And while there was great diversity in the different metabolic processes that bacteria could do there wasn't much diversity in the size and shape of bacteria.
Why would diversity of size and shape matter? Think about what a world of nothing but bacteria would look like... We're talking soup, slime, and ooze, and PU, what a smell. Enough to literally kill you - not a particularly attractive place to raise your kids. And that was what life on Earth was like for maybe three billion years. Until eukaryotic cells came along, that is.
OK, now what does life look like? There's grass, human beings, seaweed, eagles, redwood trees, moss, elephants, sharks and whales. There's microscopic single-celled sea creatures with fantastic glass houses called diatoms, there's turtles and squids and giant clams and periwinkles. Talk about different shapes and sizes and temperments. Better than 60 degrees of slime any day.
Eukaryotic cells, which is what plants, animals, fungi, and diatoms are made of, are bigger and more complex than prokaryotic (bacterial) cells. They have more parts than bacterial cells and much more DNA, 1000 times more. Eukaryotic cells have more membranes that separate and protect all the numerous parts of the cell.
Eukaryotic cells can do more things, they can specialize and link up to other cells forming organs and entire bodies. They have structures and scaffolding that allow the cells to move about like amoeba or link together like bones, skin, nerves and muscles or layers and fibers in a tree. They can secrete shells of calcium carbonates or silicates to surround and protect themselves.
Bacteria just don't have it in themselves to do any of these things. Their masters of the slime universe but what do they do besides consuming and polluting and exchanging genetic calling cards?
Let's not be disrespectful to our elders now. After all it was out of bacteria that the eukaryotic cell evolved. And that's the amazing thing that I'd like you to contemplate, because if we're looking at the “tree of life” then bacteria aren't in the branches and they aren't part of the trunk. They are in the roots.
Charles Darwin conceived of evolution as a tree with successive species as successively smaller branches, as old species went extinct and new species came into being. New species developed by inheriting new characteristics that eventually separated them from the old species.
Darwin saw the mechanism behind the generation of new species as the competitive struggle to survive. But note: the roots of a tree don't compete with each other. They each extract nutrients from the ground and send them into the tree.
Just so, the first eukaryotic cell evolved not from bacterial competition but from bacterial cooperation. That's something that Darwin didn't anticipate. Tune in next week as I describe how this symbiosis came about.
Thursday, October 22, 2009
May the Phosphorous be With You
Our brains require both sugar molecules and oxygen to remain conscious. Sugar is the product of photosynthesis. Oxygen is also the product of photosynthesis. Consciousness would not be possible without photosynthesis.
Imagine that. We think we are so independent, we can understand things not seen, see things that are no longer there, and predict things that haven't happened, yet we could not do any of these things without the existence of photosynthesizers.
Oxygen has great potential, electrically speaking. And molecules with phosphorous are the key to tapping its potential. Phosphorous is essential to bone formation and basic metabolism in most animals. It forms a part of ATP, otherwise known as Adenosine triphosphate and ADP, or Adenosine diphosphate. These are the molecules that are the workhorses of “ cellular respiration”
And DNA – the molecule of heredity, is non-functional without phosphorus. Maybe it's the power of love between Oxygen and Phosphorous that has really made it possible for life to endure longer than the mountains and the continents
Phosphorous burns with desire for Oxygen. To prove its love it will even burn under water. Carbon won't do that. So it is Phosphorous that makes Oxygen potential food rather than poison. Without Phosphorous Oxygen would have remained on the dark side of life. A deadly toxin that was killing off it's photosynthetic producers. We should be thankful for this intense love affair between Phosphorous and Oxygen, for without it we wouldn't exist.
In cellular respiration oxygen atoms are passed from one molecule to the next in a controlled stepwise process that extracts the maximum energy from an oxygen atom and makes it available to the cell for work. It is molecules of ATP and ADP that makes this possible.
Microbiologist Lynn Margulis is the scientist who first brought to our attention the idea that oxygen played a major role in shaping the direction of early evolution.
“Whereas fermentation typically produces two molecules of ATP for every sugar molecule broken down, the respiration of the same sugar molecule utilyzing oxygen can produce as many as thirty-six.”
“With greater quantities of energy available to them cyanobacteria exploded into hundreds of different forms. They spread into greater extremes of the environment, from cold marine waters to hot freshwater springs.”
“Cyanobacteria's continuing air pollution forced other organisms to acquire the ability to use oxygen too. This set off waves of speciation and the creation of elaborate forms and life cycles among them.”
“Growing, mutating and trading genes, some bacteria producing oxygen and others removing it, they maintained the oxygen balance of the entire planet.”
Oxygen has been twenty-one percent of the atmosphere for hundreds of millions of years. This is a sign of the endurance of the balance of nature. It shows that there has been a balance between photosynthesizers and respirers for at least that long.
If oxygen was much higher than 21% then all the plants on land would burn even if they were wet. But if there was much less oxygen than 21% then all animals, including humans would asphyxiate. So as animals that need to breathe and depend on plants for food we are lucky that there is just the right proportion of oxygen in the atmosphere.
How could this be? Some lovers of certainty think that there must be an intelligent designer behind it all. On the other hand, strict Darwinists, like Richard Dawkins can't explain this as anything but a coincidence. Neither considers that new properties can emerge from the ground up. In fact, living things maintain themselves. They sometimes adapt to change by changing the environment.
When too much oxygen was produced its dark side came into play. There was massive extinctions. When new forms of life evolved to take advantage of oxygen, the new form of energy, they quickly expanded in population. A new balance was created between the creatures that produce oxygen and the creatures, like us, that consume it. All this occurred over a timescale of millions of years.
There is a parallel between oxygen and oil. We humans have changed the face of the Earth much faster than any other creature. We discovered coal and oil in the ground and developed technologies like steam, diesel, and internal combustion engines to utilize the new form of energy. This occurred over a few hundred years.
Developing transportation, agricultural and extraction technologies based on machines that run on fossil fuels allowed the human population to grow rapidly because it gave us the ability to get more resources from the ground, to grow more food, and to provide more amenities for ourselves.
The greater population led to the greater utilization of fossil fuels which in turn is leading to a greater output of carbon dioxide. It is carbon dioxide that regulates global temperature and ocean acidity. Increasing the amount of carbon dioxide in the atmosphere along with other stresses on other life forms caused by increases in human population is leading to a new major extinction event.
Many creatures will go extinct. Carbon dioxide will stabilize at some higher level until millions of years from now new life forms evolve to fill the empty niches left behind by the mass extinctions and they draw down the amount of carbon dioxide in the atmosphere once again.
The balance of nature is a metaphor, but it represents a real process. In maintaining itself life uses energy and creates pollution. Pollution is toxic to many organisms and many of them die off. New life forms evolve to take advantage of the pollution creating a balance.
But remember the sand pile. Adding a single grain of sand can sometimes effect the entire pile. The global combination of all living creatures may keep the content of oxygen and carbon dioxide in the atmosphere in stable proportions until a new creature, in this case one that adds huge amounts of carbon dioxide, tips the entire system over.
Imagine that. We think we are so independent, we can understand things not seen, see things that are no longer there, and predict things that haven't happened, yet we could not do any of these things without the existence of photosynthesizers.
Oxygen has great potential, electrically speaking. And molecules with phosphorous are the key to tapping its potential. Phosphorous is essential to bone formation and basic metabolism in most animals. It forms a part of ATP, otherwise known as Adenosine triphosphate and ADP, or Adenosine diphosphate. These are the molecules that are the workhorses of “ cellular respiration”
And DNA – the molecule of heredity, is non-functional without phosphorus. Maybe it's the power of love between Oxygen and Phosphorous that has really made it possible for life to endure longer than the mountains and the continents
Phosphorous burns with desire for Oxygen. To prove its love it will even burn under water. Carbon won't do that. So it is Phosphorous that makes Oxygen potential food rather than poison. Without Phosphorous Oxygen would have remained on the dark side of life. A deadly toxin that was killing off it's photosynthetic producers. We should be thankful for this intense love affair between Phosphorous and Oxygen, for without it we wouldn't exist.
In cellular respiration oxygen atoms are passed from one molecule to the next in a controlled stepwise process that extracts the maximum energy from an oxygen atom and makes it available to the cell for work. It is molecules of ATP and ADP that makes this possible.
Microbiologist Lynn Margulis is the scientist who first brought to our attention the idea that oxygen played a major role in shaping the direction of early evolution.
“Whereas fermentation typically produces two molecules of ATP for every sugar molecule broken down, the respiration of the same sugar molecule utilyzing oxygen can produce as many as thirty-six.”
“With greater quantities of energy available to them cyanobacteria exploded into hundreds of different forms. They spread into greater extremes of the environment, from cold marine waters to hot freshwater springs.”
“Cyanobacteria's continuing air pollution forced other organisms to acquire the ability to use oxygen too. This set off waves of speciation and the creation of elaborate forms and life cycles among them.”
“Growing, mutating and trading genes, some bacteria producing oxygen and others removing it, they maintained the oxygen balance of the entire planet.”
Oxygen has been twenty-one percent of the atmosphere for hundreds of millions of years. This is a sign of the endurance of the balance of nature. It shows that there has been a balance between photosynthesizers and respirers for at least that long.
If oxygen was much higher than 21% then all the plants on land would burn even if they were wet. But if there was much less oxygen than 21% then all animals, including humans would asphyxiate. So as animals that need to breathe and depend on plants for food we are lucky that there is just the right proportion of oxygen in the atmosphere.
How could this be? Some lovers of certainty think that there must be an intelligent designer behind it all. On the other hand, strict Darwinists, like Richard Dawkins can't explain this as anything but a coincidence. Neither considers that new properties can emerge from the ground up. In fact, living things maintain themselves. They sometimes adapt to change by changing the environment.
When too much oxygen was produced its dark side came into play. There was massive extinctions. When new forms of life evolved to take advantage of oxygen, the new form of energy, they quickly expanded in population. A new balance was created between the creatures that produce oxygen and the creatures, like us, that consume it. All this occurred over a timescale of millions of years.
There is a parallel between oxygen and oil. We humans have changed the face of the Earth much faster than any other creature. We discovered coal and oil in the ground and developed technologies like steam, diesel, and internal combustion engines to utilize the new form of energy. This occurred over a few hundred years.
Developing transportation, agricultural and extraction technologies based on machines that run on fossil fuels allowed the human population to grow rapidly because it gave us the ability to get more resources from the ground, to grow more food, and to provide more amenities for ourselves.
The greater population led to the greater utilization of fossil fuels which in turn is leading to a greater output of carbon dioxide. It is carbon dioxide that regulates global temperature and ocean acidity. Increasing the amount of carbon dioxide in the atmosphere along with other stresses on other life forms caused by increases in human population is leading to a new major extinction event.
Many creatures will go extinct. Carbon dioxide will stabilize at some higher level until millions of years from now new life forms evolve to fill the empty niches left behind by the mass extinctions and they draw down the amount of carbon dioxide in the atmosphere once again.
The balance of nature is a metaphor, but it represents a real process. In maintaining itself life uses energy and creates pollution. Pollution is toxic to many organisms and many of them die off. New life forms evolve to take advantage of the pollution creating a balance.
But remember the sand pile. Adding a single grain of sand can sometimes effect the entire pile. The global combination of all living creatures may keep the content of oxygen and carbon dioxide in the atmosphere in stable proportions until a new creature, in this case one that adds huge amounts of carbon dioxide, tips the entire system over.
Thursday, October 15, 2009
Oxygen: Saviour
We're the blue planet. That's us. When you're talking planets - blue is associated with life. The blue colour comes from oxygen which makes up a large portion of the weight of a water molecule. And the blue sky also comes from the element oxygen. Oxygen comprises twenty-one percent of our atmosphere.
The colour red also has to do with oxygen. Rust, gets it's red colour because it is oxidized iron. Blood gets it's red colour from the iron and oxygen in hemoglobin. The planet Mars gets it's red colour from oxidized minerals which means that Mars used to have oxygen, probably in the form of water.
Oxygen, with it's all consuming hunger for electrons, has a lot of potential energy. But it is potential for good or ill. Free oxygen has the potential to destroy biological molecules. That's why we use bleach to get out stains. Bleaching is an oxidation process. Oxygen, by grabbing electrons from other elements, weakens covalent bonds in organic molecules leading to their disintegration.
Atmospheric oxygen is the source for ozone, a molecule made up of three oxygen atoms. Ozone is a toxic pollutant, an ingredient in automobile exhaust, but it also exists in the atmosphere where it protects life on Earth from ultraviolet rays. High up in the atmosphere a layer of ozone absorbs the ultraviolet light that would otherwise harm living creatures.
Not only does ultraviolet light harm living things but for time periods of billions of years it has even greater potential for harm. The high energy content of ultraviolet light means that it has the power to break the bonds of water molecules.
Once liberated from water, hydrogen can escape Earth's gravity into space. Without protection, over billions of years, the sun's ultraviolet rays could deplete the oceans of water.
There is evidence on Mars – the famous “Canals” - that there was once water there. Now there is no water and only a thin atmosphere of carbon dioxide. No oxygen in the atmosphere. No ozone to protect against ultraviolet light. No water anymore. And without water there is no life.
No life without water and no water without life. Earth has both. Mars had only one and now has none.
Twenty years ago there was an international treaty signed to protect the ozone layer from a man-made substance called freon. Freon was used as the main coolant in virtually all refrigerators and air conditioners. The problem was that when it was released into the air , which is what happens eventually when all fridges and air conditioners are discarded, it rose high into the atmosphere where it chemically reacting with ozone - destroying it.
Sometime during the 1990's Scientists discovered a “hole” in the Ozone in the southern hemisphere. The Ozone hole has gotten smaller since countries complied with the treaty and stopped manufacturing freon, but not before it took it's toll on Australia, where the incidence of skin cancer has increased considerably.
When bacteria first existed there was no oxygen so there was no ozone to protect living things from ultraviolet rays. It took millions of years for oxygen to reach a high enough percentage for the protective ozone layer to develop. We call that a “Time-lag. In that time bacteria were on their own to develop resistance to these deadly toxins: oxygen and ultraviolet light.
Life is autopoietic, but in maintaining itself life alters the chemistry of the Earth. And when that chemistry changed from zero free oxygen to twenty-one percent free oxygen, life developed in a radical new direction.
From photosynthesis, to – “respiration” – the utilization of oxygen to supply chemical energy to life, oxygen,which was first a pollutant and a toxin, became the basis for all new forms of life.
Tune in next week when we learn who helped Oxygen turn from the “dark side” and transform into a Creator.
The colour red also has to do with oxygen. Rust, gets it's red colour because it is oxidized iron. Blood gets it's red colour from the iron and oxygen in hemoglobin. The planet Mars gets it's red colour from oxidized minerals which means that Mars used to have oxygen, probably in the form of water.
Oxygen, with it's all consuming hunger for electrons, has a lot of potential energy. But it is potential for good or ill. Free oxygen has the potential to destroy biological molecules. That's why we use bleach to get out stains. Bleaching is an oxidation process. Oxygen, by grabbing electrons from other elements, weakens covalent bonds in organic molecules leading to their disintegration.
Atmospheric oxygen is the source for ozone, a molecule made up of three oxygen atoms. Ozone is a toxic pollutant, an ingredient in automobile exhaust, but it also exists in the atmosphere where it protects life on Earth from ultraviolet rays. High up in the atmosphere a layer of ozone absorbs the ultraviolet light that would otherwise harm living creatures.
Not only does ultraviolet light harm living things but for time periods of billions of years it has even greater potential for harm. The high energy content of ultraviolet light means that it has the power to break the bonds of water molecules.
Once liberated from water, hydrogen can escape Earth's gravity into space. Without protection, over billions of years, the sun's ultraviolet rays could deplete the oceans of water.
There is evidence on Mars – the famous “Canals” - that there was once water there. Now there is no water and only a thin atmosphere of carbon dioxide. No oxygen in the atmosphere. No ozone to protect against ultraviolet light. No water anymore. And without water there is no life.
No life without water and no water without life. Earth has both. Mars had only one and now has none.
Twenty years ago there was an international treaty signed to protect the ozone layer from a man-made substance called freon. Freon was used as the main coolant in virtually all refrigerators and air conditioners. The problem was that when it was released into the air , which is what happens eventually when all fridges and air conditioners are discarded, it rose high into the atmosphere where it chemically reacting with ozone - destroying it.
Sometime during the 1990's Scientists discovered a “hole” in the Ozone in the southern hemisphere. The Ozone hole has gotten smaller since countries complied with the treaty and stopped manufacturing freon, but not before it took it's toll on Australia, where the incidence of skin cancer has increased considerably.
When bacteria first existed there was no oxygen so there was no ozone to protect living things from ultraviolet rays. It took millions of years for oxygen to reach a high enough percentage for the protective ozone layer to develop. We call that a “Time-lag. In that time bacteria were on their own to develop resistance to these deadly toxins: oxygen and ultraviolet light.
Life is autopoietic, but in maintaining itself life alters the chemistry of the Earth. And when that chemistry changed from zero free oxygen to twenty-one percent free oxygen, life developed in a radical new direction.
From photosynthesis, to – “respiration” – the utilization of oxygen to supply chemical energy to life, oxygen,which was first a pollutant and a toxin, became the basis for all new forms of life.
Tune in next week when we learn who helped Oxygen turn from the “dark side” and transform into a Creator.
Wednesday, October 7, 2009
Why Bacteria Invented Sex
Bacteria are the ultimate survivors. They've been around for three and a half billion years. Longer than the continents, and all the mountain ranges on Earth. In contrast, the animal kingdom has been here only a paltry six hundred million years – one sixth of that time.
Bacteria are the simplest of creatures being as they were the first of all creatures to exist. They are single-celled. They are so small,that they are invisible to the naked eye. But they are not solitary creatures and they live in huge communities that are sometimes visible in the form of coloured blobs of slime, the kind you might see in a petri dish or on rotting food. It's easy to look down on them as disgusting and smelly but without them we would not exist.
It is bacteria, more than any other creature that has altered the face of the Earth – breaking down it's rocks, and adding to it's atmosphere gases such as carbon dioxide - which is crucial to Earth's temperature regulation, methane, and oxygen – without which we animals could not survive.
The technical name for bacterial cells is “Prokaryotes” , which refers to the fact that bacteria don't have a nucleus. All “Eukaryotic cells” - the kind of cells that we have in our bodies – have a nucleus. The nucleus contains all our genetic material wound up like the rubber strands in a golf ball only way tighter – if the DNA in the nucleus of one of your cells was unwound it would stretch to the moon and back several times.
That extra genetic material and the protective membrane means that eukaryotic cells can do more things and make up more complex multicellular organisms like us.
In contrast bacteria don't have as much genetic material. And the genes are looser, not packed as tight because they are not surrounded by a nuclear membrane.
But, bacteria have an advantage over eukaryotic cells. Bacteria are the original party animals. They love to hang out in huge numbers, and they're not so particular that they have to hang out with their own species. They love to mix and when they mingle they can easily exchange genetic material with whoever they please. They have no shame and the whole thing is over in seconds. Which means that bacterial evolution has been fantastically quicker than the evolution of eukaryotes
This bacterial promiscuity is the basis for genetic engineering, by the way. Because it's so easy to get bacteria to take on different genetic material bacteria can be given genes that will manufacture just about anything we want. That kind of stuff is just not possible for eukaryotic cells, thank God.
Technically speaking, “sex” is the exchange of genetic material between different organisms. It isn't necessarily tied to reproduction the way it is for bigger eukaryotic creatures. Bacteria aren't male and female because they pre-date reproductive sex.
It's immaculate conception. Bacteria can split all by themselves, And go on making millions of exact copies of themselves. They don't need love. But they need protection from toxins.
Ultraviolet light coming from the sun is hazardous to life. It can damage biological molecules. It damages DNA molecules,the genetic material for all forms of life. In Microcosmos, Lynn Margulis and Dorion Sagan's book about microbial evolution, the authors hypothesize about this connection: “The pressure to patch up damaged DNA or die induced the development of DNA repair systems. Sometimes instead of using healthy copies of their own genetic material, crowded bacteria borrowed DNA from their neighbours.”
“By adapting to life under harsh light the microcosm had invented sex. Though this first sex was different from the kind of sex animals are involved in, it was sex all the same...”
This was probably their most important means of evolving rapidly in the face of environmental danger. We now know why it was so easy for bacteria to aquire resistance to deadly toxins like anti-biotics. Bacterial sex takes advantage of the natural variety in the population to provide resistance to new toxins.
It's easy enough to say that bacteria should have just kept away from the sun's dangerous rays, and then they would have survived. Because if that's all they ever did they would never have developed photosynthesis and then we wouldn't exist. It's autopoieses. Life maintains itself. And life that survives over time does so because it adapts to Earth's changing environment. In next week's article we will discover how life can also change the odds for itself in a positive direction by altering the environment.
Bacteria are the simplest of creatures being as they were the first of all creatures to exist. They are single-celled. They are so small,that they are invisible to the naked eye. But they are not solitary creatures and they live in huge communities that are sometimes visible in the form of coloured blobs of slime, the kind you might see in a petri dish or on rotting food. It's easy to look down on them as disgusting and smelly but without them we would not exist.
It is bacteria, more than any other creature that has altered the face of the Earth – breaking down it's rocks, and adding to it's atmosphere gases such as carbon dioxide - which is crucial to Earth's temperature regulation, methane, and oxygen – without which we animals could not survive.
The technical name for bacterial cells is “Prokaryotes” , which refers to the fact that bacteria don't have a nucleus. All “Eukaryotic cells” - the kind of cells that we have in our bodies – have a nucleus. The nucleus contains all our genetic material wound up like the rubber strands in a golf ball only way tighter – if the DNA in the nucleus of one of your cells was unwound it would stretch to the moon and back several times.
That extra genetic material and the protective membrane means that eukaryotic cells can do more things and make up more complex multicellular organisms like us.
In contrast bacteria don't have as much genetic material. And the genes are looser, not packed as tight because they are not surrounded by a nuclear membrane.
But, bacteria have an advantage over eukaryotic cells. Bacteria are the original party animals. They love to hang out in huge numbers, and they're not so particular that they have to hang out with their own species. They love to mix and when they mingle they can easily exchange genetic material with whoever they please. They have no shame and the whole thing is over in seconds. Which means that bacterial evolution has been fantastically quicker than the evolution of eukaryotes
This bacterial promiscuity is the basis for genetic engineering, by the way. Because it's so easy to get bacteria to take on different genetic material bacteria can be given genes that will manufacture just about anything we want. That kind of stuff is just not possible for eukaryotic cells, thank God.
Technically speaking, “sex” is the exchange of genetic material between different organisms. It isn't necessarily tied to reproduction the way it is for bigger eukaryotic creatures. Bacteria aren't male and female because they pre-date reproductive sex.
It's immaculate conception. Bacteria can split all by themselves, And go on making millions of exact copies of themselves. They don't need love. But they need protection from toxins.
Ultraviolet light coming from the sun is hazardous to life. It can damage biological molecules. It damages DNA molecules,the genetic material for all forms of life. In Microcosmos, Lynn Margulis and Dorion Sagan's book about microbial evolution, the authors hypothesize about this connection: “The pressure to patch up damaged DNA or die induced the development of DNA repair systems. Sometimes instead of using healthy copies of their own genetic material, crowded bacteria borrowed DNA from their neighbours.”
“By adapting to life under harsh light the microcosm had invented sex. Though this first sex was different from the kind of sex animals are involved in, it was sex all the same...”
This was probably their most important means of evolving rapidly in the face of environmental danger. We now know why it was so easy for bacteria to aquire resistance to deadly toxins like anti-biotics. Bacterial sex takes advantage of the natural variety in the population to provide resistance to new toxins.
It's easy enough to say that bacteria should have just kept away from the sun's dangerous rays, and then they would have survived. Because if that's all they ever did they would never have developed photosynthesis and then we wouldn't exist. It's autopoieses. Life maintains itself. And life that survives over time does so because it adapts to Earth's changing environment. In next week's article we will discover how life can also change the odds for itself in a positive direction by altering the environment.
Friday, September 18, 2009
Oxygen: Destroyer
Oxygen gas is an anomoly. Earth's atmosphere should not be 21% molecular oxygen because oxygen is a very greedy element. It wants electrons badly and would much rather take those electrons by binding with elements on Earth's surface, then hanging around with other oxygen atoms in the atmosphere. As long as these elements are out there oxygen will "oxidize" them, which is what happens when iron rusts or something catches fire.
So why is there always 21% oxygen in the atmosphere? No other planet in our solar system has free oxygen in it's atmosphere (even though it's the third most abundant element in the universe). But no other planet in our solar system has liquid water and no other planet in our solar system has life. That's where the connection lies. It all hinges on a metabolic process called photosynthesis that was invented about two billion years ago by the bacterial ancestor of cyanobacteria or "bluegreen algae".
Lynn Margulis and Dorion Sagan, in their book, What is Life?, call photosynthesis: "the most important metabolic innovation in the history of the planet." Why? Because with photosynthesis life could derive energy from freely available sunlight for the first time.
The first bacteria probably lived off hydrogen sulphide bubbling up from volcanic vents under the sea. They derived their energy from catalyzing the hydrogen bonds, combining hydrogen with carbon to make simple sugars. Eventually, different kinds of bacteria evolved that were able to catalyze various non-organic substances such as iron and sulphur, then other bacteria evolved that could derive still more energy by fermenting the waste products of previous kinds of bacteria. Note that all early bacteria were "anaerobic", that is they did not use oxygen in any metabolic process.
There's a pattern here. First, an organism develops a way of getting energy from one substance. Then it grows and multiplies until it exhausts that resource. A crisis ensues which leads to the evolution of new life that is able to utilize new forms of energy, then those resources are exhausted and a new crisis ensues. Out of these series of life-crises bacteria came to invent every single metabolic process utilized by living things. Margulis and Sagan's point is that the development of photosynthesis temporarily bypassed this boom and bust process. By utilizing the energy from sunlight the ancestor of cyanobacteria was able to metabolize enough energy to split water molecules into hydrogen and oxygen, obtaining hydrogen from a virtually limitless source - the oceans - something that no bacteria before it was able to do.
But photosynthesis wasn't just a brilliant solution for bacteria, it rewrote the rule book for every single new life-form that has evolved since that time two billion years ago. Because, other than bacteria, all forms of life are either photosynthesizers themselves or they survive by eating photosynthesizers or by eating animals that eat photosynthesizers. That's what we mean by "the food chain".
Let's go back to that connection between oxygen in the atmosphere, water, and life. Because they had just liberated themselves from energy scarcity, the new kids on the block - bluegreen bacteria - were able to grow and multiply and grow and grow and grow until they had covered Earth's surface, wherever there was moisture. We're talking all the oceans and most of the surface rocks. We're talking a vast global empire of bluegreen slime.
But in the process of splitting water into hydrogen and oxygen, bluegreen bacteria gave off oxygen gas as a waste product. Thus the second type of crisis: pollution. Life multiplies up to it's limit, but in this case, because we are talking about sunlight and water as raw materials there was no imminent shortage. But there was a problem with pollution. Oxygen was created as a waste product and oxygen was toxic to bacteria in those times. In fact if sufficient atmospheric oxygen had been around at the time that life originated it wouldn't have originated. The oxygen would have burned up all the organic molecules before they had a chance to react with each other. Like I said, oxygen is greedy.
At first the oxygen pollution wasn't much of a problem, because oxygen was reacting with all the surface rocks, so it didn't stay long in the atmosphere. There are red bands of oxidized iron and other oxidized minerals in the layers of ancient rocks that date back to that time about two billion years ago. And, in fact, that's the strata of rocks that supplies us with iron ore to this day. From the rock record of oxidized iron we can read back the time it took for oxygen to get a foothold in the atmosphere - four hundred million years. But once everything was oxidized, all the oxygen that was produced by photosynthetic bacteria stayed in the atmosphere, creating a vast die-off of anaerobic bacteria.
Nowadays anaerobic bacteria are far less dominant, existing only in earth, mud, stagnant water, and in the guts of animals, all places where they are safe from the ravages of free oxygen.
This global event, when oxygen increased from one millionth to one fifth of the atmosphere was, according to Margulis and Sagan, in their book: MicroCosmos, "..by far the greatest pollution crisis the earth has ever endured." Unfortunately, there is no fossil record of this event, as bacteria, not having bones or hard shells have left very little in the way of fossils.
Since animals evolved,six hundred million years ago, and three billion years after bacteria evolved, there have been five major extinction events recorded in the fossil background. These were global catastrophes, where from fifty to ninety-five percent of all species on Earth were wiped out. The most famous of these was the Jurassic-Cretaceous event sixty-five million years ago, believed to be caused by a giant meteorite striking the Earth, leading to the extinction of the dinosaurs and paving the way for warm-blooded species like birds and mammals.
We are now, as we speak, involved in the sixth (or seventh, if you include "the Oxygen Holocaust") global extinction event, an event which is predicted to lead to the extinction of more than fifty percent of all species in our lifetime. This one is due to carbon dioxide pollution and habitat destruction caused by our clever utilization of a previously unused energy source - hydrocarbons. What goes around comes around, as they say. Whether we will survive it or not, is an open question. Stay tuned.
So why is there always 21% oxygen in the atmosphere? No other planet in our solar system has free oxygen in it's atmosphere (even though it's the third most abundant element in the universe). But no other planet in our solar system has liquid water and no other planet in our solar system has life. That's where the connection lies. It all hinges on a metabolic process called photosynthesis that was invented about two billion years ago by the bacterial ancestor of cyanobacteria or "bluegreen algae".
Lynn Margulis and Dorion Sagan, in their book, What is Life?, call photosynthesis: "the most important metabolic innovation in the history of the planet." Why? Because with photosynthesis life could derive energy from freely available sunlight for the first time.
The first bacteria probably lived off hydrogen sulphide bubbling up from volcanic vents under the sea. They derived their energy from catalyzing the hydrogen bonds, combining hydrogen with carbon to make simple sugars. Eventually, different kinds of bacteria evolved that were able to catalyze various non-organic substances such as iron and sulphur, then other bacteria evolved that could derive still more energy by fermenting the waste products of previous kinds of bacteria. Note that all early bacteria were "anaerobic", that is they did not use oxygen in any metabolic process.
There's a pattern here. First, an organism develops a way of getting energy from one substance. Then it grows and multiplies until it exhausts that resource. A crisis ensues which leads to the evolution of new life that is able to utilize new forms of energy, then those resources are exhausted and a new crisis ensues. Out of these series of life-crises bacteria came to invent every single metabolic process utilized by living things. Margulis and Sagan's point is that the development of photosynthesis temporarily bypassed this boom and bust process. By utilizing the energy from sunlight the ancestor of cyanobacteria was able to metabolize enough energy to split water molecules into hydrogen and oxygen, obtaining hydrogen from a virtually limitless source - the oceans - something that no bacteria before it was able to do.
But photosynthesis wasn't just a brilliant solution for bacteria, it rewrote the rule book for every single new life-form that has evolved since that time two billion years ago. Because, other than bacteria, all forms of life are either photosynthesizers themselves or they survive by eating photosynthesizers or by eating animals that eat photosynthesizers. That's what we mean by "the food chain".
Let's go back to that connection between oxygen in the atmosphere, water, and life. Because they had just liberated themselves from energy scarcity, the new kids on the block - bluegreen bacteria - were able to grow and multiply and grow and grow and grow until they had covered Earth's surface, wherever there was moisture. We're talking all the oceans and most of the surface rocks. We're talking a vast global empire of bluegreen slime.
But in the process of splitting water into hydrogen and oxygen, bluegreen bacteria gave off oxygen gas as a waste product. Thus the second type of crisis: pollution. Life multiplies up to it's limit, but in this case, because we are talking about sunlight and water as raw materials there was no imminent shortage. But there was a problem with pollution. Oxygen was created as a waste product and oxygen was toxic to bacteria in those times. In fact if sufficient atmospheric oxygen had been around at the time that life originated it wouldn't have originated. The oxygen would have burned up all the organic molecules before they had a chance to react with each other. Like I said, oxygen is greedy.
At first the oxygen pollution wasn't much of a problem, because oxygen was reacting with all the surface rocks, so it didn't stay long in the atmosphere. There are red bands of oxidized iron and other oxidized minerals in the layers of ancient rocks that date back to that time about two billion years ago. And, in fact, that's the strata of rocks that supplies us with iron ore to this day. From the rock record of oxidized iron we can read back the time it took for oxygen to get a foothold in the atmosphere - four hundred million years. But once everything was oxidized, all the oxygen that was produced by photosynthetic bacteria stayed in the atmosphere, creating a vast die-off of anaerobic bacteria.
Nowadays anaerobic bacteria are far less dominant, existing only in earth, mud, stagnant water, and in the guts of animals, all places where they are safe from the ravages of free oxygen.
This global event, when oxygen increased from one millionth to one fifth of the atmosphere was, according to Margulis and Sagan, in their book: MicroCosmos, "..by far the greatest pollution crisis the earth has ever endured." Unfortunately, there is no fossil record of this event, as bacteria, not having bones or hard shells have left very little in the way of fossils.
Since animals evolved,six hundred million years ago, and three billion years after bacteria evolved, there have been five major extinction events recorded in the fossil background. These were global catastrophes, where from fifty to ninety-five percent of all species on Earth were wiped out. The most famous of these was the Jurassic-Cretaceous event sixty-five million years ago, believed to be caused by a giant meteorite striking the Earth, leading to the extinction of the dinosaurs and paving the way for warm-blooded species like birds and mammals.
We are now, as we speak, involved in the sixth (or seventh, if you include "the Oxygen Holocaust") global extinction event, an event which is predicted to lead to the extinction of more than fifty percent of all species in our lifetime. This one is due to carbon dioxide pollution and habitat destruction caused by our clever utilization of a previously unused energy source - hydrocarbons. What goes around comes around, as they say. Whether we will survive it or not, is an open question. Stay tuned.
Tuesday, September 1, 2009
The Carbon Connection
“Only connect!... Only connect the prose and the passion and both will be exalted, and human love will be seen at its height. Live in fragments no longer. Only connect...” E. M. Forster
What do we mean when we say that life is an interdependent web? Partly it's a metaphor that points to the way that living things make up of a vast network of interrelations. How are living things connected? All life-forms are made from the same types of molecules: water, proteins, carbohydrates, lipids, DNA, and RNA; All life forms metabolize energy with the help of enzymes made from amino acids; All life-forms share a common ancestor, according to Darwin's theory of evolution; All living things ultimately depend on the Sun's energy; All living things share materials and substances that are only available on Earth; All living things interact cooperatively and competitively with other living things.
All well and good, but what makes this vast and intricate global interdependence possible? If I was to pick one thing it would be the element Carbon. You may recall that I said in the previous article that each element is a kind of character. Carbon is the most extroverted sociable element there is. He is an exceptionally friendly fellow. He makes bonds with everybody and they are often strong bonds called covalent bonds that require more energy than the other two kinds of bonds to break apart. Diamonds, the hardest substance known, are made from pure carbon bonded covalently.
OK, lots of elements bond covalently, but what differentiates Carbon from everyone else is that he can't get enough of himself. Carbon loves to bond with himself and does it over and over in chains, and in rings, in two dimensional sheets and in three dimensional tetrahedons. There is literally no end to the number of carbon atoms that can join together to form chains of fantastically diverse lengths.
And Carbon is a multi-tasker extraordinaire. So while he's linking up to carbon copies of himself, he's always socializing with the other elements on the side, especially with Oxygen,Hydrogen and Nitrogen. These chains of carbons with various side links then form the backbones for literally all the molecules of life: the proteins, enzymes, carbohydrates, fats, etc... It's the incredibly complex shapes that are created by carbon bonds that are the key to life.
Life is autopoietic - it maintains itself over time. But in order to maintain itself a living organism must perform many functions , all of which require a vast variety of different kinds of molecules and only Carbon makes that possible .
But that's not all, because Carbon, in the form of carbon dioxide, is essential in regulating Earth's surface temperature and the acidity of the ocean and our bodies. These are big jobs and somebody's got to do them, or life as we know it would cease to exist. So why Carbon?
You'd think that a substance that makes up only .03% of the Earth's atmosphere would hardly be up for the job, but it's the size of the molecule that matters when it comes to the greenhouse effect. And carbon dioxide with three atoms, one Carbon and two Oxygen, is a bigger molecule than the two other main components of the atmosphere – Nitrogen and Oxygen - which each form molecules of only two atoms each. Note that water and methane, which are also bigger sized molecules are even more potent greenhouse gases than carbon dioxide but they don't remain in the atmosphere as long as carbon dioxide does, so their effect is smaller.
We think of carbon dioxide as being the bad guy because of global warming but in actual fact without carbon dioxide the Earth would be a ball of ice. It's just that our industries and transportation systems are producing too much carbon dioxide right now. But that's for another article.
When carbon dioxide dissolves in water it forms a weak solution of carbonic acid and bicarbonate which together makes it a buffer. Chemical buffers keep the pH of a solution more stable by neutralizing acids and bases, thus keeping the ocean and our blood at near constant pH. But if too much carbon dioxide is dissolved in water then it loses it's buffering quality and becomes an acid. When that happens in our blood stream we die from acidosis. The thing is, the metabolic reactions that sustain life only occur in a narrow range of temperatures and pH, so Carbon's role in regulating temperature and ocean pH is vital to life. The problem is when too much carbon gets into the atmosphere both those systems go out of whack and then we get into trouble.
When you think about it, we take Carbon for granted. Carbon has got a lot of responsibility for supporting life as we know it . We oughta give him some slack instead of making his job harder. After all, he's kinda like that guy Atlas, the one who holds up the Earth in Greek mythology. Maybe somebody should write a book about him – a “green” Atlas Shrugged.
What do we mean when we say that life is an interdependent web? Partly it's a metaphor that points to the way that living things make up of a vast network of interrelations. How are living things connected? All life-forms are made from the same types of molecules: water, proteins, carbohydrates, lipids, DNA, and RNA; All life forms metabolize energy with the help of enzymes made from amino acids; All life-forms share a common ancestor, according to Darwin's theory of evolution; All living things ultimately depend on the Sun's energy; All living things share materials and substances that are only available on Earth; All living things interact cooperatively and competitively with other living things.
All well and good, but what makes this vast and intricate global interdependence possible? If I was to pick one thing it would be the element Carbon. You may recall that I said in the previous article that each element is a kind of character. Carbon is the most extroverted sociable element there is. He is an exceptionally friendly fellow. He makes bonds with everybody and they are often strong bonds called covalent bonds that require more energy than the other two kinds of bonds to break apart. Diamonds, the hardest substance known, are made from pure carbon bonded covalently.
OK, lots of elements bond covalently, but what differentiates Carbon from everyone else is that he can't get enough of himself. Carbon loves to bond with himself and does it over and over in chains, and in rings, in two dimensional sheets and in three dimensional tetrahedons. There is literally no end to the number of carbon atoms that can join together to form chains of fantastically diverse lengths.
And Carbon is a multi-tasker extraordinaire. So while he's linking up to carbon copies of himself, he's always socializing with the other elements on the side, especially with Oxygen,Hydrogen and Nitrogen. These chains of carbons with various side links then form the backbones for literally all the molecules of life: the proteins, enzymes, carbohydrates, fats, etc... It's the incredibly complex shapes that are created by carbon bonds that are the key to life.
Life is autopoietic - it maintains itself over time. But in order to maintain itself a living organism must perform many functions , all of which require a vast variety of different kinds of molecules and only Carbon makes that possible .
But that's not all, because Carbon, in the form of carbon dioxide, is essential in regulating Earth's surface temperature and the acidity of the ocean and our bodies. These are big jobs and somebody's got to do them, or life as we know it would cease to exist. So why Carbon?
You'd think that a substance that makes up only .03% of the Earth's atmosphere would hardly be up for the job, but it's the size of the molecule that matters when it comes to the greenhouse effect. And carbon dioxide with three atoms, one Carbon and two Oxygen, is a bigger molecule than the two other main components of the atmosphere – Nitrogen and Oxygen - which each form molecules of only two atoms each. Note that water and methane, which are also bigger sized molecules are even more potent greenhouse gases than carbon dioxide but they don't remain in the atmosphere as long as carbon dioxide does, so their effect is smaller.
We think of carbon dioxide as being the bad guy because of global warming but in actual fact without carbon dioxide the Earth would be a ball of ice. It's just that our industries and transportation systems are producing too much carbon dioxide right now. But that's for another article.
When carbon dioxide dissolves in water it forms a weak solution of carbonic acid and bicarbonate which together makes it a buffer. Chemical buffers keep the pH of a solution more stable by neutralizing acids and bases, thus keeping the ocean and our blood at near constant pH. But if too much carbon dioxide is dissolved in water then it loses it's buffering quality and becomes an acid. When that happens in our blood stream we die from acidosis. The thing is, the metabolic reactions that sustain life only occur in a narrow range of temperatures and pH, so Carbon's role in regulating temperature and ocean pH is vital to life. The problem is when too much carbon gets into the atmosphere both those systems go out of whack and then we get into trouble.
When you think about it, we take Carbon for granted. Carbon has got a lot of responsibility for supporting life as we know it . We oughta give him some slack instead of making his job harder. After all, he's kinda like that guy Atlas, the one who holds up the Earth in Greek mythology. Maybe somebody should write a book about him – a “green” Atlas Shrugged.
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