Sexual Selection and Mortality Rates Yvette Aranas & Mercedes Pineda Dr. Mills Psych 452 Kruger, D.J. & Nesse, R. M. (2004). Sexual selection and the Male: Female Mortality Ratio. Evolutionary Psychology. 2, 66 - 85.

Why Women Live Longer Than Men. Video: Why Women Live Longer Than Men. Kruger, D.J. & Nesse, R. M. (2004). Sexual selection and the Male: Female Mortality Ratio. Evolutionary Psychology. 2, 66 - 85.

Introduction: The Study Looked at the lifespan in 20 different countries and the past 70 years, in only 5 of those countries. Results show similarities of MR among the different countries across all causes of death. Differences with sexual selection interaction, along with aspects of culture and environment contributes to the high male MR. Mortality ratio increases as general mortality rates decrease. Kruger, D.J. & Nesse, R. M. (2004). Sexual selection and the Male: Female Mortality Ratio. Evolutionary Psychology. 2, 66 - 85.

Main critical points Females live longer: Males tend to have competition amongst themselves for chances at sexual reproduction. Males are willing to risk more & invest less time in the repair capacity. The survival of offspring depends on maternal care rather than paternal care. Kruger, D.J. & Nesse, R. M. (2004). Sexual selection and the Male: Female Mortality Ratio. Evolutionary Psychology. 2, 66 - 85.

Continued… Historical changes significantly affected the mortality rate: Decline of infectious diseases. Increase of mortality [in]directly caused by behavior through: Increase population size Mobility Domestication of animals Public health measures Medicine Increase availability of tobacco, cars, weapons, etc. Kruger, D.J. & Nesse, R. M. (2004). Sexual selection and the Male: Female Mortality Ratio. Evolutionary Psychology. 2, 66 - 85.

Continued… In modern days: Male lifespan peak at young adulthood rather than in later adulthood as in females; Highest differences for direct behavioral causes of death Mortality is now due to more external causes compared to earlier times. Explain what the difference is of external and internal causes of death are. Kruger, D.J. & Nesse, R. M. (2004). Sexual selection and the Male: Female Mortality Ratio. Evolutionary Psychology. 2, 66 - 85.

Figure 1: 2000 M:F MR by Age and Cause in the USA From: 2000 United States mortality data from the National Center for Health Statistics Double Y-axis graph of the M:F MR for each cause of death, representing absolute M/F mortality rates on the left side, and M:F MR on the right ratio scale. The Y-intercept is set at 1.0, so any points above the Y-axis represent mortality rates that are higher for men than for women. For all causes in the USA: shows a higher male mortality rate than females across the lifespan. OVERALL: Mortality rate peaks at 2.94 in the 20-24 year age range and slowly decreases from there on out. Kruger, D.J. & Nesse, R. M. (2004). Sexual selection and the Male: Female Mortality Ratio. Evolutionary Psychology. 2, 66 - 85.

Figure 2: Composition of Excess Male Life Years Lost by Cause Cardiovascular disease accounted for the greatest proportion [26%]. Internal causes of death comprised 41% , external causes of death accounted for 35% - and the other 23% causes were not accounted for in the study. The ratio of male to female total life years lost from death before the age of 80 is 1:58 to 1. In the same scenario, before the age of 50 the ratio is a dramatic difference. For every 10 premature female deaths, 16 men died prematurely. Kruger, D.J. & Nesse, R. M. (2004). Sexual selection and the Male: Female Mortality Ratio. Evolutionary Psychology. 2, 66 - 85.

Figure 3: M:F MR in 2000 by Age in 20 Countries Graph shows the cross-national comparison among all 20 countries. Shows higher male than female mortality rates for nearly all ages - all peaking around the same, at sexual maturity. Kruger, D.J. & Nesse, R. M. (2004). Sexual selection and the Male: Female Mortality Ratio. Evolutionary Psychology. 2, 66 - 85.

Time to test your knowledge! Kruger, D.J. & Nesse, R. M. (2004). Sexual selection and the Male: Female Mortality Ratio. Evolutionary Psychology. 2, 66 - 85.

2. Which one is NOT a historical or cultural influence on M:F MR? 1. This study examined the M:F MR over the course of a lifespan in ___ countries. 10 5 20 15 2. Which one is NOT a historical or cultural influence on M:F MR? Domestication of animals Availability of automobiles Availability of antibiotics Feminism Answers: 1. C Feminism Kruger, D.J. & Nesse, R. M. (2004). Sexual selection and the Male: Female Mortality Ratio. Evolutionary Psychology. 2, 66 - 85.

3. From an evolutionary perspective, why do women generally outlive men? Women are not wired to take any risks at all. The survival of the offspring depends more on maternal care. Culture tells males to take more risks; the fact that males take these risks has nothing to do with evolution at all. Actually, women DON’T out live males, males outlive females. 3. B - offspring depend more on maternal care. Kruger, D.J. & Nesse, R. M. (2004). Sexual selection and the Male: Female Mortality Ratio. Evolutionary Psychology. 2, 66 - 85.

4. In humans, females generally have a higher mortality rate than males. True False 5. The results showed that the peak of external causes for mortality rate in males generally occurred during young adulthood. 6. M:F MR are exactly the same in all countries examined in this study. 4. False 5. True 6. False Kruger, D.J. & Nesse, R. M. (2004). Sexual selection and the Male: Female Mortality Ratio. Evolutionary Psychology. 2, 66 - 85.