Discussion Questions: 3. Humans exhibit a Type 1 survivorship. Type 1 survivorship curves are characterized by high initial survivorship rates then a rapid decline in survivorship late in life. The mortality rate is very low in early life, and many of the individuals of the population will live to old age. 4. The cohort of 1850-1859 shows a more rapid increase in mortality rate later in life than the 1900-1909 cohort.
During the late 19th century, after the Civil War, many young people were put to work in Reconstruction projects, some of which were dangerous, including the building of the transcontinental rail service, which caused some younger deaths. Also, the American Industrial Revolution occurred between 1820 and 1870, so the young men and women born in the 1850-1859 cohort were more exposed to industry and factory work.
Because of newer machinery, and underdeveloped safety plans and unions, machine work and factory jobs could be quite dangerous, and as this cohort aged, the work became more difficult and dangerous for the older individuals. In 1922, there were medical advancements that led to the discovery of insulin, and penicillin was discovered in 1928. Due to these medical advances, it would make sense that the 1900-1909 cohort was living to an older age than the 1850-1859 cohort.
Air conditioning was also invented in 1932, reflecting less heat related injuries and deaths. 5. When comparing the mortality rates of the men and women of the 1900-1919 cohort, it is noticed that most of these individuals lived through both WWI (1914-1918) and WWII (1939-1945). The men born earliest in the 1900-1909 cohort could have joined WWI near the end which could have caused injuries and deaths, and most of these men could have been involved in WWII, also causing injury and death.
In addition to fighting, and possibly dying during the war, the injuries, both mental and physical, could have affected them later in life causing infection, disease, or mental illness, which could have contributed to suicide. The mortality rates do not seem that different from one another until the end of the trend. This could be because women began to work in unsafe conditions in factories while the men were at war, and when the men returned and many families began to have children, some many in a short period of time, there was an increase in labor related deaths.
It has been hypothesized that in general, women may live longer throughout history because they generally have less stress, and participate in less unhealthy activities that are damaging such has over-consumption of alcohol and smoking, and women tend to have better diets than men. Some also believe that it is much deeper in our genetics because many miscarriages tend to be male and many other animals exhibit the same trend, where the females tend to outlive the males.