The first step was colonies of bacteria. Even today, these colonies blur the line between single- and multi-cellular life.
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The first step was colonies of bacteria. Even today, these colonies blur the line between single- and multi-cellular life. Bacteria have been discovered which use chemical pathways to communicate with other nearby bacteria.
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How did sexual reproduction originate?
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Sex, by definition, depends on both male and female acting together. As sex evolved, there would have been some incompatibilities causing sterility (just as there are today), but these would affect individuals, not whole populations, and the genes that cause such incompatibility would rapidly be selected against.
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Why do the millions of “missing links” remain missing?
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Every species is a missing link; all species evolve. In addition, transitional organisms only survive for a short time, since they are evolving towards being a stable species.