Saturday 6 August 2016

Intelligently Evolving Elephants

Genetic connectivity across marginal habitats: the elephants of the Namib Desert - Ecology and Evolution.

The importance of intelligent, memetic evolution, as opposed to genetic evolution, is being increasingly recognised especially in sentient species. Groups of sentient animals can appear to be a different species based on lifestyle, habitat, social organisation, etc and yet be genetically almost indistinguishable. Pods of killer whales, for example, may have very different hunting strategies and occupy different parts of the ocean but differ only from other pods by culture.

But creationists shouldn't get too excited; this isn't the magic intelligence of their imaginary magic friend but the intelligence of sentient species in being able to direct their own evolution to a limited extent, and so to make themselves more adaptable to environmental change.

Memes, or memory genes' are notional units of cultural inheritance by which cultures are passed from one generation to the next. Like genes, memes can change gradually over time and across a range due to selection pressures as one cultural variant may be more fitted to survival and reproduction in one part of the range and another variant may be more fitted to another.

One example of this exact situation was published very recently in Ecology and Evolution by a team from the Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, USA. The team, led by Alfred Roca, professor of animal sciences, studied a group of African elephants that live in the Namibian Desert and which have adapted to hot, dry desert conditions quite different to the conditions endured by African savannas and forest elephants. There are reported subtle morphological differences between these elephants and the savanna elephants which had led some to speculate that they might be a different species or subspecies.

However, the team found that the two groups had the same DNA; what differs is their cultures.

Locally isolated populations in marginal habitats may be genetically distinctive and of heightened conservation concern. Elephants inhabiting the Namib Desert have been reported to show distinctive behavioral and phenotypic adaptations in that severely arid environment. The genetic distinctiveness of Namibian desert elephants relative to other African savanna elephant (Loxodonta africana) populations has not been established. To investigate the genetic structure of elephants in Namibia, we determined the mitochondrial (mt) DNA control region sequences and genotyped 17 microsatellite loci in desert elephants (n = 8) from the Hoanib River catchment and the Hoarusib River catchment. We compared these to the genotypes of elephants (n = 77) from other localities in Namibia. The mtDNA haplotype sequences and frequencies among desert elephants were similar to those of elephants in Etosha National Park, the Huab River catchment, the Ugab River catchment, and central Kunene, although the geographically distant Caprivi Strip had different mtDNA haplotypes. Likewise, analysis of the microsatellite genotypes of desert-dwelling elephants revealed that they were not genetically distinctive from Etosha elephants, and there was no evidence for isolation by distance across the Etosha region. These results, and a review of the historical record, suggest that a high learning capacity and long-distance migrations allowed Namibian elephants to regularly shift their ranges to survive in the face of high variability in climate and in hunting pressure.

Yasuko Ishida, Peter J. Van Coeverden de Groot, Keith E. A. Leggett, Andrea S. Putnam, Virginia E. Fox, Jesse Lai, Peter T. Boag, Nicholas J. Georgiadis, Alfred L. Roca.
Genetic connectivity across marginal habitats: the elephants of the Namib Desert.
Ecology and Evolution, 2016
; DOI: 10.1002/ece3.2352

Copyright © 1999 - 2016 John Wiley & Sons, Inc. Open access. Reprinted under terms of Creative Commons International license 4.0 (CC BY 4.0)

As the authors point out in their introduction:

The ability of species such as elephants to learn and change their behavior can limit the need to genetically adapt to a new environment and can allow species to expand their range to novel marginal habitats that differ sharply from core habitats (Sutter and Kawecki 2009). Learning may allow a population to favor a new habitat specialization in a novel environment, thus increasing its isolation from other populations (Beltman and Metz 2005). Paradoxically, learning can also buffer against the effects of natural selection, thereby lowering the pressure for local genetic adaptations to develop (Sutter and Kawecki 2009).

The ability of species such as elephants to learn and change their behavior means that genetic changes are not critical for them to adapt to a new environment. The behavioral changes can allow species to expand their range to novel marginal habitats that differ sharply from the core habitat...

Regardless, these elephants should be conserved. Their knowledge of how to live in the desert is crucial to the survival of future generations of elephants in the arid habitat, and pressure from hunting and climate change may only increase in the coming decades.

The desert elephants are also rumored to be larger, which may put them at greater risk for trophy game hunting. Animals that live in these marginal environments are vulnerable, and their numbers do not bounce back very quickly.

Alfred Roca,
Professor of animal sciences. Lead author.
Quoted in Carl R. Woese Institute for Genomic Biology press release.
So a highly intelligent species can quickly adapt to environmental stress and opportunity not by the slow, undirected process of genetic evolution, but by adapting its behaviour with varying degrees of intelligence. Humans actually provide a very good example of this in the form of different cultural adaptations to the many different environments in which we live.

The Namibian elephants have evolved a way of life quite different to that of savanna elephants but one which relies entirely on older, female elephants passing on their knowledge to the younger ones. For example, to keep cool, they cover themselves with urine-soaked sand. They also need to know where to find scarce water and vegetation over a vast territory. They have learned to store, and regurgitate on demand, several gallons of water in pouches beneath their tongues.

These elephants play an important role in the ecosystem across a much larger territory than normal for other elephants as they dig and maintain water holes and create paths to them. For this reason alone they need to be conserved because these essential survival and ecologically important skills will inevitably be lost if the population is lost.

This, of course, is simply another example of how replicators replicating slightly imperfectly in a selective environment not only evolve towards survival in that environment but casually and without direction form alliances with other replicators. In this particular case, memes and elephant genes have co-evolved so allowing the African elephants to extend their range and become more quickly responsive to environmental change.

This is exactly what happened in early human evolutionary history so enabling us to expand worldwide from a specialised environment in Africa. The result is an amazing variety of evolved cultures complete with inherited folklore, music, literature, superstitions, food, styles of clothing and social organizations each of which is the current endpoint of its own evolution.

Incidentally, did anyone notice how the Theory of Evolution is a theory in crisis? Me neither! It seems the glorious day when biologists the world over abandon the TOE with it's abundant evidence and explanatory power and adopt en masse a primitive, evidence-free Bronze Age superstition is about as far off as the glorious day when Jesus comes back and kills everyone who disagrees with American Christian fundamentalists so they can have everything for themselves.

'via Blog this'

submit to reddit

No comments :

Post a Comment

Obscene, threatening or obnoxious messages, preaching, abuse and spam will be removed, as will anything by known Internet trolls and stalkers, by known sock-puppet accounts and anything not connected with the post,

A claim made without evidence can be dismissed without evidence. Remember: your opinion is not an established fact unless corroborated.

Web Analytics