Short Essay on Earth (290 Words)
Short Essay On Planet Earth Free Essays - StudyMode
For this essay’s purposes, the most important ecological understanding is that the Sun provides all of earthly life’s energy, either (all except nuclear-powered electric lights driving photosynthesis in greenhouses, as that energy came from dead stars). Today’s hydrocarbon energy that powers our industrial world comes from captured sunlight. Exciting electrons with photon energy, then stripping off electrons and protons and using their electric potential to power biochemical reactions, is what makes Earth’s ecosystems possible. Too little energy, and reactions will not happen (such as ice ages, enzyme poisoning, the darkness of night, food shortages, and lack of key nutrients that support biological reactions), and too much (such as , ionizing radiation, temperatures too high for enzyme activity), and life is damaged or destroyed. The journey of life on Earth has primarily been about adapting to varying energy conditions and finding levels where life can survive. For the many hypotheses about those ancient events and what really happened, the answers are always primarily in energy terms, such as how it was obtained, how it was preserved, and how it was used. For life scientists, that is always the framework, and they devote themselves to discovering how the energy game was played.
Short essay on the Structure of planet Earth
The , which began 443 mya, is short for the , lasting “only” 24 million years and ending about 419 mya. The Silurian was another relatively hot period with shallow tropical seas, but . But the ice caps eventually shrank, which played havoc with the sea level and caused minor extinction events (, , ), the last of which ended the Silurian and also created more Middle East oil deposits. Reefs made a big comeback, extending as far as 50 degrees north latitude (farther north than where I live in ). According to the model, oxygen levels rose greatly during the Silurian and rebounded from a low in the mid-Ordovician; it may have reached 25% by the early Devonian, which followed the Silurian. Coincident with rising oxygen levels, more giants appeared. Scorpion-like were the largest arthropods ever, and the near the Devonian’s oxygen highpoint. The first land-dwelling animals - , , and - came ashore during the Silurian between 430 mya and 420 mya. The appeared and of the first insects ., Donald Canfield believed that the gigantism among arthropods and other oxygen effects were due to Earth's atmosphere beginning to reach modern levels for the first time in the eon of complex life, not that it reached higher than modern levels. I expect the oxygen controversy to outlive me.