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Fuel the evolution of a natural variation among individuals in the population. This change not only hit Charles Darwin and Alfred Wallace, the first inventor of the ideological evolution by natural selection, and became one of the core view that the request was born the idea of evolution. Change is still a prominent feature of the population scattered, because viruses and velociraptors. No matter wherever you go in the world can the natural populations, organisms different from each other. Therefore, the evolution of fuel prices surrounded by the United States sometimes piling up like woodstove winter diet, low graduation sometimes the attention of high-level span in the classroom. Like any engine without fuel, without variation unrelated to the work of evolution, said a whimpering stopped. However, engine performance requirements, not only has enough fuel.           Forces That Drive Biological Evolution     Variability is a hallmark of biological populations, the real-life reflection of a production line independent of machines. Populations of manufactured goods might pour out of the controlled crucible of a steel foundry, perhaps pounded into molds of unforgiving iron by humorless hammers, but organisms form in the slosh of protoplasm and the vagaries of tomorrow's weather. Like homemade cookies, real organisms in natural populations sport badges of individuality that make them intricately different from one another. The differences can be subtle, like a finch with a thicker beak, or profound, like a whale with legs. But whatever they consist of, these differences add a pervasive texture to the background of the biological world, a texture missing among the manufactured one.   Variation serves as an integral part of the fundamental mechanisms of evolution. Evolution acts as a deep-thrumming engine of biological change and, like any engine, it has fuel, an energy converter and a gearbox that exerts force. Just as your car engine can't let its pistons go on vacation, all the parts of the engine of evolution must function together. If we consider each part separately (like looking at a plastic model spaceship before it's assembled), then we can build a better understanding of each component and not glue the warp drive in upside down.   The fuel of evolution consists of the natural variation between individuals in a population. This variation struck both Charles Darwin and Alfred Wallace, the first inventors of the idea of evolution by natural selection, and became one of the core observations that demanded the birth of the evolutionary idea. Variation remains a prominent feature of populations as disparate as viruses and velociraptors. Wherever you look in the world of natural populations, organisms differ from one another. Thus, the fuel of evolution surrounds us—sometimes piled high like a woodstove's winter diet, sometimes at low ebb like a graduating senior's attention span in class. Like any engine without fuel, evolution without variation has nothing to work on—it comes to a whimpering halt. But the engine's operation demands more than just adequate fuel.   An energy converter is required, a role filled by natural selection itself, operating when the spectrum of slight physical differences alters the lottery of life and changes how an organism lives or dies. Do these physical differences make it more difficult to feed offspring? Do they change how well a male can attract a mate? If so, then natural selection begins to act—altering the makeup of the current generation or altering which individuals have the most young in the next generations. This selection acts like a piston converting the exploding energy of gasoline to the smooth ride of a luxury car: it creates a critical link between the variation of a population and the real-life consequences of that variation.   Inheritance of variation appears as third element—the gearbox that transmits changes made by natural selection down through the generations so that new generations possess a novel genetic legacy. Without inheritance, the evolutionary engine races without effect, each generation dawning the same as the one before. But when offspring inherit the variations that were successful in their parents, then the next generation can be more successful than the one before.   Evolution by natural selection thus relies upon three interlocking elements that must function together like the legs of a tripod — variation, differences in reproduction, and inheritance. When all three elements appear together, evolution becomes the expected outcome of biological life. Many biological systems shift, change, and evolve as we watch in the lab or in the field. Even replicating molecules, jostling one another in glittering test tubes, can be chemical mimics of the evolutionary process. As long as they possess all three evolutionary elements, populations of simple nucleic acid molecules can evolve overnight into tighter, leaner versions of themselves.           — Stephen R. Palumbi, The Evolution Explosion: How Humans Cause Rapid Evolutionary Change, Chapter 3 - Engine of Evolution                     Indexes/15