Dec 8, 2010 · “Reinforcement” and the origin of species December 8, 2010 • 8:13 am The conventional definition of “a species” amongst evolutionary biologists is “a group of organisms whose members interbreed among themselves, but are separated from other groups by genetically-based barriers to gene flow.”

Jan 4, 2017 · Now all of this represents our best current take about the origin of species, which is summed up in the technical book I wrote with Allen Orr in 2004, Speciation. These views were not developed by Darwin, as he didn’t have a clear idea of the relationship between species and reproductive isolation.

Nov 24, 2020 · On the Origin of Species by Means of Natural Selection, or the Preservation of Favoured Races in the Struggle for Life. That’s the title of the first five editions; in the Sixth (the last), the initial word was dropped. There will be a quiz.

Aug 5, 2022 · In 1831 Mr. Patrick Matthew published his work on ‘Naval Timber and Arboriculture,’ in which he gives precisely the same view on the origin of species as that (presently to be alluded to) propounded by Mr. Wallace and myself in the ‘Linnean Journal,’ and as that enlarged on in the present volume. Unfortunately the view was given by Mr ...

Jul 1, 2022 · That is, in the first edition of On the Origin of Species in 1859, Darwin mentioned that some “variations” (he meant what we called “the result of mutations”) could have no effect on survival or reproduction, and therefore whose fate would be determined by the vagaries of chance. This is what the neutral theory, made prominent by Tomoko ...

Feb 10, 2025 · The interesting thing to me was that although people have argued fiercely in the literature about what a “species” is, when it comes to speciation, the process whereby species are formed in nature, virtually every paper equates speciation with “the origin of reproductive barriers.” That is an implicit admission that yes, species are ...

Feb 25, 2024 · Here, then, we have two species that were given the same name, perhaps because they had similar morphologies or culturing requirements, or because the genetic distance between them (indicating the time of separation) was pretty low, suggesting a recent origin. These “cryptic species” were seen in 21 of the 91 named bacterial species.

Apr 12, 2024 · More birds today, and you can enlarge the photos by clicking on them. Captions and IDs by Ephraim. and I request readers’ help with those species that aren’t identified. One of the 18 species of Galápagos finches studied by Darwin [JAC: readers’ IDs welcome] Galápagos flycatcher (Myiarchus magnirostris) . Another common endemic species.

Jan 27, 2025 · I just opened a book that was perhaps the most influential volume of my career, Mayr’s 1963 Animal Species and Evolution. I found this sentence on p. 604: “A shift into a new niche or adaptive zone is, almost without exception, initiated by a change in behavior.” Mayr was a smart guy, and was probably right.

Jan 27, 2025 · Or, maybe all these things were selected at once and were not strictly initiated (as per Mayr) by a change in behavior. I’ve read almost all (maybe all) of Mayr’s books, starting with his 1942 Systematics and the Origin of Species. In addition to being a great empirical scientist, he was a great theorist.