For this post, I created the new post category “wild speculations”, because it is indeed a wild speculation. Some species even evolved as a result of human activities. One example for human-induced speciation would be the plant Erythranthe peregrina, which is a hybrid of two species introduced to Britain, E. guttata and E. lutea, which hybridized, created a sterile hybrid which experienced allopolyploidization (doubling of the genome) and produced a fertile hybridogeneous species. It was discovered relatively recently (2011). Without human intervention, this species would not exist. It is also possible that other kinds of human intervention, such as wiping out species, can result in a speciation event over a longer period of time in evolutionary terms because the niches that become vacant have potential for the evolution of new species. I have the suspicion that it is possible that the wisent might be such a case.
The story begins around 600kya, when there was only one Bos species in Europe, Bos (bison) schoetensacki. Around that time, a second bovine species migrated to Europe, either by island hopping from Africa or via the continental route from western Asia, the aurochs. Only a few millennia after the aurochs arrived in Europe, B. schoetensacki disappeared from the fossil record. I think it is quite possible that B. schoetensacki was outcompeted by the newly arrived aurochs as both bovines must have occupied a similar niche and the extinction shortly after the arrival of the aurochs is just as suspicious as the fact that bison subsequently were absent from interglacial faunal assemblages of Europe until the very late Pleistocene around 13kya, when bison (now in the form of the wisent) re-entered the interglacial megafauna assemblage. I call that the “bison gap” (roughly 600kya-13kya). If the aurochs outcompeted bison in Europe, why did they rejoin the interglacial fauna and why only so recently? B. bison priscus, which was most likely the ancestral form of the wisent, was present in Europe during all of the recent glacial periods. So, it could have evolved into an interglacial bison type much earlier, right after the extinction of B. schoetensacki if the aurochs did not outcompete bison in Europe – if it did, it is an open question why this competition was not a factor anymore at the end of the Pleistocene and during the Holocene.
Several thousand years earlier, there was another event that had an impact on the European megafauna: Palaeoloxodon antiquus and Stephanorhinus hemitoechus died out, most likely because of hunting from humans. Elephant extinction reduced competition for other grazers, at the same time forest growth became more common. Aurochs could not invade denser forest while bison are adapted to consume more wooden vegetation and can invade denser forest. This might have created new ecological space for bison to re-enter the interglacial faunal assemblage.
This guess is impossible to verify, but I think it must have one or several reasons why bison were absent from the European interglacial faunal assemblages for over 500.000 years.
If this guess is true, it would illustrate how nature is dynamic and might respond to anthropogenic impacts not necessarily always in a diversity-reducing way but sometimes also in a diversity-increasing way.
Recientemente se llevaron a cabo estudios geneticos que rebelaron que el bisonte europeo resulto de una hibridacion entre el bisonte estepario y el uro y que este hibrido contiene hasta un 10% de composicion genetica de bos primigenius ademas se cree que eventualmente este bisonte europeo hibrido fue sustutuyendo al bisonte estepario y este relevo quedo plasmado en el arte rupestre por otro lado al migrar a America por Beringia el bisonte estepario dio lugar a 4 o5 especies de las cuales la unica en sobrevivir fue la especie mas pequeña y que tambien tiene potencial para hibridar con los desendientes domesticos del uro.
ReplyDeleteDear Daniel,
ReplyDeleteAs you probably know,
New Genetic studies have identified a rare mitochondrial DNA (mtDNA) haplogroup, previously associated with the endangered Przewalski’s horse, within the modern Finnhorse breed.
https://link.springer.com/article/10.1007/s10914-020-09517-6#:~:text=A%20recent%20study%20of%20the,2015).
This finding suggests a unique, ancient genetic link between the Finnhorse and eastern primitive breeds, pointing to a diverse, native maternal ancestry in the breed's history. The presence of Przewalski-like mitochondrial DNA in Finnhorses indicates that some maternal lineages in the Finnish horse may have ancient, primitive origins, rather than solely descending from imported, more recently domesticated stocks.
This discovery links the Finnhorse to a rare, "primitive" haplotype, which is generally not found in many modern domestic horse breeds.The Finnhorse breed should be valorised in breeding back projects in your opinion?
In particoular I can imagine the draught type that is the oldest of the Finnhorse types, and has had its own separate breeding section since the studbook was first split in 1924
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