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9 Cards in this Set
- Front
- Back
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Scientists use what they call _______, which allows them to test hypotheses and theories and to develop concepts and ideas.
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Scientfic method.
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Aristotle believed insects and frogs were generated from nonliving components in moist soil. This early hypothesis concerning the origin of living organisms is known as _______.
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Spontaneous generation.
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Adherents of the _______ maintained that life processes were not solely determined by the laws of the physical universe, but rather, they also depend on some vital force, or vital principal.
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Vitalist doctrine.
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The composition of today's atmosphere differs markedly from that found here when life was just beginning to evolve. At that time the atmosphere contained far more _______.
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Hydrogen.
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When the chemical conditions of the early oceans and atmosphere are duplicated in the lab and provided with an energy source in the form of electrical sparks, _______ and _______ have been formed.
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Organic molecules and amino acids.
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________ has been shown to serve as a support and as a catalyst for the diversity of organic molecules involved in what we define as living processes.
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Clay
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When researchers heated amino acids under dry conditions, long polypeptide chains were produced. When these chains were places in a hot-water solution and then allowed to cool, the polypeptides coalesced into small spheres called _______, within which certain substances were trapped. Molecules that make more molecules could have become enclosed in such cell-like containments.
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Microspheres.
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It was proposed that germs would have been carried to earth from another part of the universe via meteorites. Such transport was finallt discounted however, because _______.
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Heat generated during entry into the earth's atmosphere would burn any germs to a crisp.
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_______, the comprehensive theory proposed in 1905 by the Swedish chemist Svante Arrhenius, stated that spores of bacteria that could survive the long periods of cold traveled alone through interstellar space, pushed along by the physical pressure of starlight.
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Panspermia.
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