The Elements of Evolution (43-2) Adaptation continued


For the littlest ones, evolution is a matter of self-selection. Microbes carve their own evolutionary path: deciding how to adapt themselves to environmental conditions via self-induced genetic modifications. Horizontal gene transfer often facilitates the process.

For macrobes, adaptation often appears via bodily change (phenotypically). But physical changes may be the tip of the iceberg to functional transformations, including behaviors.

Predation has long been recognized as a key ecological factor for adaptive responses in morphology, behavior, and alterations in life-history variables. But predation risk also drives the evolution of social complexity. Under threat of predation groups become more cohesive. Organisms stay together to minimize risk. Proximity evolves social interaction regimes. If membership in a group becomes a precondition for survival, predation adaptively affects mating and breeding regimes as well as everyday life.

The significance of predation for the evolution of social complexity can be well illustrated by behavioral and morphological adaptations of highly social animals showing division of labor, such as eusocial insects and cooperatively breeding fishes. Predation risk has the greatest explanatory power of social complexity. ~ Dutch evolutionary biologist Frank Groenewoud

Adaptation ultimately involves alterations in the genetic fabric. But adaptation is not necessarily confined to being within an organism. Solutions may involve environmental transformations (envirotype). Organisms and their ecology are entangled.

Organisms are constructed in development, not simply “programmed” to develop by genes. Living things do not evolve to fit into preexisting environments, but co-construct and coevolve with their environments, in the process changing the structure of ecosystems. ~ Kevin Laland et al

◊ ◊ ◊

Evolution plays an important role in range spread. ~ American environmental biologist Christopher Weiss-Lehman

Dispersal and speciation have long been considered interrelated, yet range extension of a population has long been thought merely a matter of demographic metrics, such as dispersal inclinations and rates of birth and mortality. Extending the range of a population commonly involves adaptive evolution when habitat conditions differ from those where the core of the population live. Environmental pressures at a population’s edges stimulate adaptation which may eventuate into speciation.