ABSTRACT
The diversity of topics examined in this chapter reflects the inherent complexity of the aging process. Despite the rapid progress of research in the last few decades, studies of aging and longevity still remain fragmented and incomplete. This first section compares longevity among animal species to identify common traits that may correlate with longevity. Senescence is assumed to occur in all living organisms and to lead to death. Hence, senescence is considered as being universal, progressive, deleterious, and irreversible (1). However, in certain plants and invertebrates, aging may progress very slowly or may not occur at all.
