Week3 Draft5

Evolution and acclimation are often confused with one another. The former is a change over time in a population or a species such that the descendants differ from the ancestors. However, acclimation is change in an individual's physiology. Other differences between the two are that changes brought about by evolution are heritable, while the changes due to acclimation are not passed onto the next generation. One aspect that confuses many students in biology is that the ability to acclimate itself is heritable due to evolution, but the acclimation of an individual itself is not heritable. An example of evolution is observed in polar bears, which have evolved their white fur, matching the color of the snow. Random mutations lead to this white color, and because of the fitness advantage, the genes for white fur were passed on, changing the population. An example of acclimation is the tanning of human skin after long durations in the sunlight. This physiological change came about, but is reversable, and cannot be passed onto the next generation. If a person tans, their child will not be born the skin color of the parent's tan. However, humans have the ability to tan because evolution allowed them to tan. Those who were able to tan were more protected from the sun, giving them a fitness advantage. A fitness advantage is the advantage that comes from an adaptation allowing an organism to more likely reproduce and pass on their genes.