There have been some controversial examples of

There have been some controversial examples of - host...

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There have been some controversial examples of sympatric speciation documented in the literature. The apple maggot fly ( Rhagoletis pomonela ) mates and lays eggs on a specific host, originally Hawthorn. In 1864 Rhagoletis was found on apple trees that had been introduced to regions where hawthorn grew. In early 1960's Rhagoletis was found on cherry. This host race formation has been argued as an incipient stage of sympatric speciation. Advantage of this model is that the temporal framework is reasonably well documented and the species in question is an agricultural pest so it is likely that it will receive further study and the issue can be settled. Model invoking a survival locus (S) and a
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Unformatted text preview: host selection locus (H) with each with new mutant alleles that shift survival and selection to the new host (e.g., apple from Hawthorn). Allochronic speciation was proposed as a model where species differentiated in time. Crickets of the genus Gryllus were taken as an example because species with virtually identical songs and morphology had evolved as spring adults versus fall adults (overwinter as juveniles or eggs, respectively). The model may apply but this particular example was shot down by phylogenetic analysis which showed that the two "allochronic species" ( Gryllus veletis and Gryllus pennsylvanicus are actually distantly related in the genus (see figures)....
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This note was uploaded on 11/06/2011 for the course BIO BSC1010 taught by Professor Gwenhauner during the Fall '10 term at Broward College.

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