Science & Me presents The ever changing flu virus and elephants with short tusks: What do they have in common? Katy

1. Science & Me presents The ever changing flu virus and elephants with short tusks: What do they have in common? Katy Klymus Kektgb@mizzou.edu How can changes in an environment lead to changes in an organism's traits? We will look at examples from creatures as diverse as viruses and elephants to explore this idea of evolution. We will learn how this process occurs and how it affects us in our daily lives. The Science & Me Series ScienceAndMe@missouri.edu University of Missouri Office of Science Outreach & The Division of Biological Sciences Resources WHO: World Health Organization www.who.int CDC: Center for Disease Control and Prevention www.cdc.gov Understanding Evolution http://evolution.berkely.edu/ Introduction to Evolutionary Biology www.talkorigins.org

2. The ever changing flu virus and elephants with short tusks- What do they have in common? Change in the environment favors individuals with certain traits; not all individuals survive to reproduce The Flu- Why do we need a new vaccine every year? Vaccines enable the immune system to recognize viruses more quickly. Changes in a virus trait can create new variants of flu virus. These new strains are better able to survive and reproduce because they are not recognized by the immune system. These strains have a higher fitness. These strains reproduce more than the others, passing on the new trait. This new flu strain must be fought with a different vaccine. Why do we need to get a new flu vaccine each year, but we only get a polio vaccine once? Because the flu virus can change through time and is no longer affected by last year’s vaccine. The process of change over time in an organism’s traits is termed Biological Evolution A difference in fitness or ability to reproduce; brown bugs have a higher chance of survival and reproduce more than the green bugs Natural selection can lead to evolution, it requires: Variable traits Coat color is green or brown Short Tusked Elephants-Where did all the long tusked elephants go? Scientists have observed that the average tusk size in African elephants has decreased by half in the last 150 years. They believe this is due the selective killing of large tusked elephants for the ivory trade. Short tusked elephants are not killed, thus they can reproduce more than the large tusked elephants, spreading the genes for short tusks. The population is now composed of more individuals with the adaptive trait Heritable traits Brown bugs produce brown offspring Green bugs produce green offspring