Author Topic: How much space do you need to evolve a new mammal?  (Read 58 times)

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Offline Emergence

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How much space do you need to evolve a new mammal?
« on: May 16, 2018, 02:56:49 AM »
Answer: None, you just need God! j/k  ;)

Research on mammal speciation conducted on the Phillipines found that the answer is "only a tenth of what was previously thought to be the minimum, probably less".


The original paper is available as open access publication in the Journal of Biogeography:


Quote from: Abstract
Aim
To investigate the influence of oceanic island area on speciation by small mammals, in the context of other land vertebrates.

Location
Mindoro Island (9,735 km2), an oceanic island in the Philippines.

Methods
Extensive field surveys on Mindoro, followed by sequencing one mitochondrial and three nuclear genes for use in phylogenetic, population genetic and coalescent-based analyses, and by morphometric analysis of craniodental data.

Results
Our analyses documented the presence on Mindoro of an endemic clade of probably four species of Apomys, subgenus Megapomys. The common ancestor likely arrived from Luzon Island across a narrow sea channel between 2.4 and 1.5 Ma; the four probable species occur allopatrically, with variation in their ranges along elevational gradients. Mindoro thus becomes the smallest oceanic island on which speciation by small mammals has been documented.

Main conclusions
A review of land-living vertebrates suggests that bats and large mammals have the greatest area requirements for speciation, whereas frogs, lizards, birds and small mammals have lower and similar minimum area requirements. However, with the exception of Anolis lizards, data are scattered and limited; much research is needed to document the impact of island area on speciation. The existence of a lower limit implies that the biological processes that influence species richness do not operate equivalently along a gradient of island areas: speciation within islands may not contribute to changes in species richness below some limit, unlike colonization and extinction, which operate at all island sizes
« Last Edit: May 16, 2018, 03:06:36 AM by Emergence »
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Offline Graybeard

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Re: How much space do you need to evolve a new mammal?
« Reply #1 on: July 05, 2018, 06:54:19 PM »
You'd think that the answer would be "big enough to supply more than enough food for creatures in question to get started." Once the population has outgrown, or threatens to outgrow, the local food supply, they have to move and adapt to an area that it initially inhospitable - those with a genetic predisposition to survive in the new environment will succeed or die - if they die, it does not matter - eventually some who can survive will make it, and evolution is on its way.

To encourage evolution a very diverse habitat is helpful (The island in question has plains and mountains.) as would be areas that are difficult to access - once these areas have been accessed, then an isolated population can get down to the business of breeding from within their own gene-pool.
Nobody says “There are many things that we thought were natural processes, but now know that a god did them.”