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Unformatted text preview: being better adapted. Populations of living things evolve Evolution refers to changes in the genetic composition of a population. Genetic changes may result in changes in the physical or behavioral characteristics of the individuals. A mutation is a change in the genetic instructions (DNA) of an individual. The change is usually harmful but occasionally it is beneficial. Any beneficial mutations that occur are likely to spread within a population because individuals that possess the mutations will have higher reproductive output and they will reproduce the mutation. Beneficial mutations are therefore likely to result in evolutionary change. Evolutionary change has led to diversity among organisms. To date, approximately 1.8 million different species of organisms have been identified. Biologists estimate that there are between 10 and 200 million species on earth....
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- Fall '10