Free Essays on Making Life Changes
free essay on Change in My Life - No Membership Fees
The energy from controlled fire allowed humans to , , and socially organize in new ways. Humans commandeered energy that otherwise and used it for immediate human benefit. It was also the first great human robbery. All heterotrophs “” energy from other life forms to live. The primary exception is the symbiosis that . But no animal had ever robbed energy from ecosystems on that scale before. By making fires, humans were liberating many times the energy that their biological processes used - energy that could have fed forest ecosystems. While humans were only using deadwood, it was the least destructive to forest ecosystems. But when humans began burning forests to flush out animals to kill and make biomes suitable for animals to hunt, they were destroying and altering ecosystems on a vast scale. A cord of wood provides about four years of the calories that fuel a human adult’s body, and one hectare can provide a sustainable annual harvest of about ten years of human calories. A family of four using a hectare for firewood on a sustainable basis would be using more than twice their caloric intake for burning wood. Very little of that released energy would benefit humans if they burned it over a campfire, as humans did for the entire epoch of the hunter-gatherer; that liberated energy largely went straight into the sky. The direct benefit to humans would be the energy that went into cooking food, what warmed human flesh, what was used to make tools, and the benefits of scaring off predators and providing light at night. More indirect benefits would have been ecosystem changes to provide human-digestible calories, such as American Indians burning the woodlands and plains to make environments conducive to animals that they could easily hunt. In , the earliest epochs are the most uncertain, but saying that hunter-gatherer humans used 2.5 times their dietary calories in their economy is probably, perhaps greatly, understating the case. That 5% efficiency number is also a rough estimate, and both numbers could be refined by a scientifically performed effort. Maybe somebody has already done it. The numbers in that table for subsequent epochs are more accurate, and the most accurate of all are those for , and I live in one. The increases in efficiency became more modest with each epoch as the limits of were approached.
Changes in My Life - Essay by - Anti Essays
This essay has presented Earth’s many changing faces during its journey. Earth had molten beginnings, was , and may have . Later, and and . Earth experienced swings from to conditions as atmospheric gases dramatically changed, continents moved, and vast and of complex life played out on land and sea. But the changes happened over timescales of millions and billions of years, not hundreds. No climate scientist will deny that carbon dioxide traps infrared radiation and warms Earth’s atmosphere. The vented enough carbon dioxide into the atmosphere to create 200 million years of Greenhouse Earth conditions, when reptiles ruled Earth. Volcanism waned and around 150-to-100 mya. By 35 mya, and the Antarctic ice sheet began forming. Every paleoclimate study I have seen places greenhouse gas (and primarily carbon dioxide) concentrations as the primary determinant of global surface temperatures, after the Sun's radiation, but the Sun's output is considered to have been exceptionally stable and has risen slowly over the eons. , usually by accentuating the carbon dioxide with a positive feedback effect that may have reached runaway conditions at times.