Ecologically mediated selection against hybrids, caused by hybrid phenotypes fitting poorly
into available niches, is typically viewed as distinct from selection caused by epistatic …

The accumulation of data on the genomic bases of adaptation has triggered renewed
interest in theoretical models of adaptation. Among these models, Fisher's geometric model …

In recent years, scientists have realized that evolution can occur on timescales much shorter
than the" long lapse of ages" emphasized by Darwin—in fact, evolutionary change is …

Understanding the processes that drive phenotypic diversification and underpin speciation
is key to elucidating how biodiversity has evolved. Although these processes have been …

Evolutionary hypotheses to explain the greater numbers of species in the tropics than the
temperate zone include greater age and area, higher temperature and metabolic rates, and …

Adaptation often proceeds from standing variation, and natural selection acting on pairs of
populations is a quantitative continuum ranging from parallel to divergent. Yet, it is unclear …

The endpoint of speciation has been viewed as complete isolation and the absence of gene
flow between species. If the influx of genes from another species is maladaptive because …

Genetic incompatibilities are an important component of reproductive isolation. Although
theoretical studies have addressed their evolution, little is known about their maintenance …

Interactions between alleles and across environments play an important role in the fitness of
hybrids and are at the heart of the speciation process. Fitness landscapes capture these …

Natural selection plays a variety of roles in hybridization, speciation, and admixture. Most
research has focused on two extreme cases: crosses between closely related inbred lines …