Overdose: If someone has overdosed and has serious symptoms such as passing out or trouble breathing, call 911. Otherwise, call a poison control center right away. US residents can call their local poison control center at 1-800-222-1222. Canada residents can call a provincial poison control center. Symptoms of overdose may include: unusual excitement, fast/irregular heartbeat, seizures.
Natural Variation Natural variation includes internal and external variability influences such as the solar Schwabe cycle, oceanic cycles, seasonal influences based on changes caused by the interaction of the various natural oscillations in the climate system.
In a changing environment, natural selection will favor variations Variation: The differences among individuals in a population. that result in a better fitness in the new environment, resulting in adaptation and evolution. Directional selection Directional selection Directional Selection: A type of selection that removes individuals from one end of a phenotypic distribution and thus causes a shift in the distribution. occurs when natural selection favors one extreme of continuous variation. Over time, the favored extreme will become more common and the other extreme will be less common or lost.