What is Senescence?
Describe the two mechanisms ultimately responsible for aging according to the evolutionary theory of aging. Using the graphical model presented in Figure 12.7 and reproduced here, explain the process by which a mutation that causes senescence might be favored by selection using the graphical model presented in Figure 12.7 and reproduced below; using the same model, explain why a mutation that causes death might be only weakly selected against.
Senescence is the process of aging, both in whole organisms and individual cells within these organisms. Researchers have focused heavily on human senescence, looking at how humans age, and why, in the hopes of perhaps someday treating the problems associated with senescence, which range from eventual breakdown of the human body to mental problems. Senescence is also a topic of interest more generally in the field of biology, as it occurs in all living organisms on Earth. The process of senescence is incredibly complex, and accompanied with a myriad of chemical and physical reactions. As organisms age, they slowly break down, experiencing tissue death and more general malfunction, whether they are plants, animals, fungi, or one-celled organisms. Without the processes of senescence, organisms would be immortal, only subject to death if they were severely injured or killed, and the Earth would be choked with living organisms as a result. From a biological standpoint, senescence promotes
