1. What transitions has Earth gone through and why?
The young earth was anything but habitable. Radioactive elements decaying within its mass and impacts from debris raining down form space generated intense heat. There was no life during this era. Is called the Hadean era and was formed about 4.5 billion years ago. Hadean comes from the Greek word Hades which means “Hell”. That’s how hot the Earth’s temperature was.
The next phase in the Earth’s history was the Archean era. It existed from about 2.5 to 3.8 billion years ago. This was the first time that any rock development was discovered.
Next was the Proterozoic era. It dated .6 to 2.5 billion years ago. During this era the Earth became frozen and it is also known as the Snowball Earth. Shortly after the Snowball Earth period, the first eukaryotic cells evolved. All life during this time period was single celled. These three eras were known as Precambrian.
The Paleozoic time period was next and dated about .5 billion years ago. It was broken into several different categories. Permian, which included another near extinction of life. It’s possible that maybe many volcanoes erupted causing a greenhouse effect. It killed 80-85% of all life forms. Then there was the Pennsylvanian, Mississippian, Devonian, Silurian, Ordovician, and Cambrian time periods. The Cambrian Explosion is when most life forms were discovered.
The next period was the Mesozoic era. It is dated about 66.4 to 245 million years ago. It was also broken into categories: Critaceous, Jurassic and Triassic. During the Triassic time period dinosaurs existed. This was another time that the Earth became extinct due to a possible meteorite.
The final time period of the Earth’s history is the Cenozoic era. It is when human life was discovered and is dated from the present to 66.4 million years ago.
2. What can cause the dynamic balance in the atmosphere to change and what influence do humans have?
Things that may change the dynamic balance in the atmosphere are climate variables such as temperature, precipitation, and vegetation and elements that control the greenhouse effect, such as clouds and albedo.
Most importantly humans are increasing greenhouse gas levels in the troposphere, which raises Earth’s surface temperature by increasing the amount of heat radiated from the atmosphere back to the ground.
Temperature and moisture levels are major variables shaping Earth’s weather patterns. By increasing atmospheric concentrations of greenhouse gases through activities such as burning fossil fuels, humans are changing the plants radiative balance. This process is altering global temperatures and moisture levels, so we can expect that it will change Earths weather patterns.
Human actions affect the carbon cycle such as fossil fuel combustion and deforestation. Burning fossil fuels speeds up the “weathering” of buried hydrocarbons, and deforestation accelerates the natural pace at which forests die and decompose, releasing carbon back to the atmosphere.
3. How does today’s increased population and industrial use impact the oceans?
Despite their global scope, the oceans are highly vulnerable to human impacts, including marine pollution and over fishing. Most profoundly scientists increasingly agree that human induced climate change could affect ocean temperatures, circulation, and carbon cycling over the next century.
The mixing of the warm and cold and salt and fresh water play a major role in the circulation of the ocean. It could possibly disrupt the flow along the so called conveyor belt or even end it.
When optimal light, temperature, and nutrient conditions occur, and limited numbers of grazers (larger organisms that feed on phytoplankton) are present, plankton population explosions called blooms occur. Grazers reproduce more slowly than phytoplankton, so it takes time for them to catch up to their food supply. Major blooms can color...
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