Big+Idea+5-7+Evolution

Populations of organisms evolve by natural selection.

 * Individual organisms with certain traits are more likely than others to survive and have offspring.
 * Every organism has a set of instructions for specifying its traits.
 * Hereditary information (set of instructions) is contained in genes, located on chromosomes.
 * Each gene carries a single unit of information.
 * A human cell contains many different genes.
 * Organisms reproduce and pass their genes to the next generation (their offspring).
 * Genes can randomly change or mutate, causing changes in certain traits of the offspring.
 * Changes in environmental conditions can affect the survival of populations and entire species.
 * Small differences in organisms can accumulate in successive generations so that descendents are very different from their ancestors.
 * Extinction of a species occurs when the environment changes and the adaptive characteristics of a species are insufficient to allow its survival.

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