Download Measuring evolutionary fitness in humans

Measuring evolutionary fitness in humans
Virpi Lummaa
University of Sheffield
UK
Documenting evolutionary processes is often difficult in human behavioural ecology, given the
hurdles in measuring the two requirements for evolution by natural selection: heritable trait
variation and differential reproduction and survival associated with traits. First, selection can vary
with age, and determining such age-related changes is particularly important in long-lived species
with extended post-reproductive period. Second, selection can also vary across environments, and
both the early and adult environments can have long-term consequences for individual success.
Finally, trait heritabilities themselves can vary both across different ages and environments, and
traits can be positively or negatively correlated, negative correlations indicating difficulties in
maximizing both traits simultaneously. I have investigated these questions in particular to unravel
why women experience menopause and prolonged postreproductive lifespan thereafter with
significant investments made to provide care to the grandchild generation and, perplexingly, why
male lifespan (and often reproductive lifespan, too) is comparable to that of their sterile partner, but
grandfathers appear to have less important role in contributing to the success of future generations. I
use detailed pedigree records of historical Finnish families, combining information on individual
longevity and reproductive success with variation in social, demographic, nutritional and climatic
conditions to document varying selection pressures. This talk will highlight the usefulness of
adopting an integrative approach and the need to combine data on long-term measures of fitness
with information on the underlying genetic variation and trade-offs across different ages and
environments to understand human life-history evolution.