We burn fossil fuels dead but undecayed plant material to generate energy. Water vapor and carbon dioxide are by products. Carbon dioxide is the subject of an upcoming 1S1P assignment and we'll see these two equations again there and when we study the greenhouse effect and global warming. Here's a detail that I often forget to mention when this material is covered in class and something you probably don't need to remember.
The argon we have in the atmosphere apparently comes from the radioactive decay of potassium in the ground. Three isotopes of potassium occur naturally: potassium and potassium are stable, potassium is radioactive and is the source of the argon in the atmosphere.
Geological evidence of early oxygen in the earth's oceans and atmosphere The following figure is the first page in the packet of photocopied ClassNotes. This somewhat confusing figure shows some of the important events in the history of the earth and evolution of the atmosphere. There are 5 main points I want you to take from this figure. Points 1 - 3 are the most important. First, Point 1: the earth is thought to be between 4.
If you want to remember the earth is a few billion years old that is probably close enough. A relatively minor point shown in the figure: the formation of the earth's molten iron core was important because it gave the earth a magnetic field. The magnetic field deflects the solar wind and prevents the solar wind from blowing away our present day atmosphere.
Stromatolites Point 2 are geological features, column-shaped structures made up of layers of sedimentary rock, that are created by microorganisms living at the top of the stromatolite I'm not a geologist and I've never actually seen a stromatolite, so this is all based on photographs and written descriptions.
Much older 3. Stromatolites Blue green algae grows at the top of the column, under water but near the ocean surface where it can absorb sunlight. As sediments begin to settle and accumulate on top of the algae they start to block the sunlight.
The cyanobacteria would then move to the top of this sediment layer and the process would repeat itself. In this way the stromatolite column would grow layer by layer over time. You might be wondering why we are learning about stromatolites.
It's because the cyanobacteria on them were able to produce oxygen using photosynthesis. Living stromatolites are found in a few locations today. The two pictures above are from Lake Thetis left and Shark Bay right in Western Australia the two photos above and the photograph below come from this source. The picture was probably taken at low tide, the stromatolites would normally be covered with ocean water.
It doesn't look like a good place to go swimming, I would expect the top surfaces of these stromatolites to be slimy. Hamelin Pool in Western Australia is a World Heritage Area, the stromatolites there are the oldest and largest living fossils on earth see this source for more information Living stromatolites at Highborne Cay in the Bahamas.
Banded iron formation Point 3 refers to the banded iron formation, a type of rock formation. These rocks are 2 - 3 billion years old maybe older and are evidence of oxygen being produced in the earth's oceans. Here are a couple of pictures of samples of banded iron formation rock that I passed around in class. The main thing to notice are the alternating bands of red and black. The rocks are also relatively heavy because they contain a lot of iron.
The next paragraph and figure explain how these rocks formed. Rain would first of all wash iron ions from the earth's land surface into the ocean this was at a time before there was any oxygen in the atmosphere. Once in the ocean, the iron ions reacted with oxygen from the cyanobacteria living in the ocean water to form hematite or magnetite.
These two minerals precipitated out of the water to form a layer on the sea bed. This is what produced the black layers. Periodically the oxygen production would decrease or stop rising oxygen levels might have killed the cyanobacteria or seasonal changes in incoming sunlight might have slowed the photosynthesis.
During these times of low oxygen concentration, red layers of jasper would form on the ocean bottom. The jasper doesn't contain as much iron. Eventually the cyanobacteria would recover, would begin producing oxygen again, and a new layer of hematite or magnetite would form.
This difference in surface gravity is due to a number of factors — mass, density, and radius being the foremost. When applied to a spherical body like a planet with a given mass, the surface gravity will be approximately inversely proportional to the square of its radius. When applied to a spherical body with a given average density, it will be approximately proportional to its radius. Credit: geodesy. For instance, Mars has a mass of 6. It also has a mean radius of 3, The surface gravity of Mars can therefore be expressed mathematically as: 0.
Implications: At present, it is unknown what effects long-term exposure to this amount of gravity will have on the human body. However, ongoing research into the effects of microgravity on astronauts has shown that it has a detrimental effect on health — which includes loss of muscle mass, bone density, organ function, and even eyesight.
Basically, the effects of long-term exposure to gravity that is just over one-third the Earth normal will be a key aspect of any plans for upcoming manned missions or colonization efforts. Their proposed mission calls for many months in space to get to Mars, and for those volunteering to spend the rest of their lives living on the Martian surface.
Learning more about Martian gravity and how terrestrial organisms fare under it could be a boon for space exploration and missions to other planets as well. And as more information is produced by the many robotic lander and orbiter missions on Mars, as well as planned manned missions, we can expect to get a clearer picture of what Martian gravity is like up close.At just 0. Both planets have roughly the same amount of land surface area, sustained polar caps, and both have a similar tilt in their rotational axes, affording each of them strong seasonal variability. But if you picture hitting something with a hammer and breaking it, the pieces usually fly off in different directions. Photosynthesis in its most basic form is shown in the chemical equation above.
Eventually the cyanobacteria would recover, would begin producing oxygen again, and a new layer of hematite or magnetite would form. In this way the stromatolite column would grow layer by layer over time. Mars Compared to Earth: The differences between Mars and Earth are all crucial for the existence of life as we know it. The Rosetta spacecraft has photographed material being ejected from the comet you'll find a nice animation here. This difference in surface gravity is due to a number of factors — mass, density, and radius being the foremost. There are a couple of answers to that question.
Ozone in the upper atmosphere began to absorb the dangerous and deadly forms ultraviolet light and life forms at the surface could then begin to safely move from the oceans onto land prior to the buildup of ozone, the ocean water offered protection from UV light. During these times of low oxygen concentration, red layers of jasper would form on the ocean bottom.
There are 5 main points I want you to take from this figure.
This is what produced the black layers. This somewhat confusing figure shows some of the important events in the history of the earth and evolution of the atmosphere. How Can We Live on Mars? Photosynthesis releases oxygen as a by product. In addition to the red and black layers, you see yellow layers made of fibers of quartz in the samples passed around class.
Photosynthesis Once plant life had developed sufficiently and once plants had moved from the oceans onto land, photosynthesis became the main source of atmospheric oxygen. Where did the oxygen in our atmosphere come from? There are 5 main points I want you to take from this figure.