Case report
Reconstructing Life History of Hominids and Humans
Douglas E. Crews
Linda M. Gerber
Abstract
Aspects of life history, such as processes and timing of development, age at maturation,
and life span are consistently associated with one another across the animal kingdom.
Species that develop rapidly tend to mature and reproduce early, have many offspring,
and exhibit shorter life spans (r-selection) than those that develop slowly, have
extended periods of premature growth, mature later in life, reproduce later and less frequently,
have few offspring and/or single births, and exhibit extended life spans (K-selection).
In general, primates are among the most K-selected of species. A suite of highly
derived life history traits characterizes humans. Among these are physically immature
neonates, slowed somatic development both in utero and post-natally, late attainment of
reproductive maturity and first birth, and extended post-mature survival. Exactly
when, why, and through what types of evolutionary interactions this suite arose is currently
the subject of much conjecture and debate. Humankind’s biocultural adaptations
have helped to structure human life history evolution in unique ways not seen in other
animal species. Among all species, life history traits may respond rapidly to alterations
in selective pressures through hormonal processes. Selective pressures on life history
likely varied widely among hominids and humans over their evolutionary history. This
suggests that current patterns of human growth, development, maturation, reproduction,
and post-mature survival may be of recent genesis, rather then long-standing adaptations.
Thus, life history patterns observed among contemporary human and chimpanzee
populations may provide little insight to those that existed earlier in hominid/
human evolution.
Keywords
biocultural adaptations; evolution; growth and development; senescence
Hrčak ID:
28072
URI
Publication date:
16.6.2003.
Visits: 2.702 *