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In this video it is claimed that Darwin's finches arrived at Galápagos Islands just a few hundred years ago. Have there been new speciations over the past 200 years?

asmani
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According to oneZoom.org (see the node of interest here), the large ground finch and the large cactus finch share a common ancestor about 170k years ago. Looking among Darwin finches on oneZoom.org, I could not find a more recent speciation event. I could not find their references for their estimates though.

However, part of the difficulty here lies in the exact definition of species one is willing to use (see this post). While it is not reported in oneZoom.org, grant and grant (2009) reported an evidence of reproductive isolation within the G. fortis species.

Speciation, the process by which two species form from one, involves the development of reproductive isolation of two divergent lineages. Here, we report the establishment and persistence of a reproductively isolated population of Darwin’s finches on the small Gala´pagos Island of Daphne Major in the secondary contact phase of speciation. In 1981, an immigrant medium ground finch (Geospiza fortis) arrived on the island. It was unusually large, especially in beak width, sang an unusual song, and carried some Geospiza scandens alleles. We followed the fate of this individual and its descendants for seven generations over a period of 28 years. In the fourth generation, after a severe drought, the lineage was reduced to a single brother and sister, who bred with each other. From then on this lineage, inheriting unusual song, morphology, and a uniquely homozygous marker allele, was reproductively isolated, because their own descendants bred with each other and with no other member of the resident G. fortis population. These observations agree with some expectations of an ecological theory of speciation in that a barrier to interbreeding arises as a correlated effect of adaptive divergence in morphology. However, the important, culturally transmitted, song component of the barrier appears to have arisen by chance through an initial imperfect copying of local song by the immigrant. The study reveals additional stochastic elements of speciation, in which divergence is initiated in allopatry; immigration to a new area of a single male hybrid and initial breeding with a rare hybrid female.

Remi.b
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  • Thanks. The second question is not much necessary to me, so I will remove it. – asmani Apr 14 '18 at 14:52
  • It is some kind of a rule though that the OP cannot just change the question (or only for mild clarifications) after someone has answered it though. You're now realizing part of the problem of why one must always restrict a post to a single question! – Remi.b Apr 14 '18 at 14:54
  • I would rather advice, restricting the current post to the second question only as it has already been answered (although relatively poorly answered) and open a new post for the first question. – Remi.b Apr 14 '18 at 14:56
  • You're right. I edited the question. – asmani Apr 15 '18 at 10:05
  • I think this article implies there have been new speciations? https://evolution.berkeley.edu/evolibrary/news/100201_speciation – asmani Apr 15 '18 at 10:06
  • I read your post about the definition of species. I was curious what's the definition of lineage, but I don't have enough reputation to comment there. Doesn't lineage refer to an individual? – asmani Apr 17 '18 at 16:40
  • From wikipedia, An evolutionary lineage is a temporal series of organisms, populations, cells, or genes connected by a continuous line of descent from ancestor to descendent. Lineages are subsets of the evolutionary tree of life Feel free to open a post if anything is unclear. I've added a link to the wikipedia page onto my answer to "How could humans have interbred with Neanderthals if we're a different species?" – Remi.b Apr 17 '18 at 16:52
  • I opened a new question: https://biology.stackexchange.com/questions/72521/usage-of-lineage-over-species

    Not sure if it's not against the rules, since it looks kind of personal.

     – asmani Apr 17 '18 at 17:54
  • I think it is totally fine to cite someone (whether the cited text was published on biology.SE or anywhere else) and ask for more information. Don't worry about that – Remi.b Apr 17 '18 at 18:09