ausblenden:
Schlagwörter:
niche evolution; ecological opportunity; biodiversity
Zusammenfassung:
Adaptive radiation of a lineage into a range of organisms with
different niches underpins the evolution of life’s diversity. Although
the role of the environment in shaping adaptive radiation
is well established, theory predicts that the evolvability and niche
of the founding ancestor are also of importance. Direct demonstration
of a causal link requires resolving the independent effects
of these additional factors. Here, we accomplish this using experimental
bacterial populations and demonstrate how the dynamics
of adaptive radiation are constrained by the niche of the founder.
We manipulated the propensity of the founder to undergo adaptive
radiation and resolved the underlying causal changes in both
its evolvability and niche. Evolvability did not change, but the propensity
for adaptive radiation was altered by changes in the position
and breadth of the niche of the founder. These observations
provide direct empirical evidence for a link between the niche of
organisms and their propensity for adaptive radiation. This general
mechanism may have rendered the evolutionary dynamics of
extant adaptive radiations dependent on chance events that determined
their founding ancestors.
