Incidentally Chaz - I would be rather proud to co-tutor "Eugenics 101" with you. My mate Phil and I used to present HRM in the UK 101 via Sooty and Sweep puppets and allude to a large, vicious dog called Bozo to gain crowd control. The presence of my Anti Anti-Social Dalek would no doubt help with class motivation, as no doubt, would re- opening the pits to provide real work.
On 30 Dec, 22:34, chazwin <[email protected]> wrote: > Sorry dear, this IS the smoking room: ladies not allowed. > > On Dec 30, 9:29 pm, gabbydott <[email protected]> wrote: > > > > > Would the gentlemen please go over to the library and smoke there. > > Thank you. > > > On 30 Dez., 18:47, chazwin <[email protected]> wrote: > > > > Reminds me of a joke. > > > > What is the difference between a truck load of babies and a truck load > > > of ping pong balls???? > > > > .. > > > . > > > > You can't unload a truck load of ping pong balls with a pitch-fork. > > > > On Dec 30, 4:52 pm, "Chris Jenkins" <[email protected]> > > > wrote: > > > > > Hmmm...you have a point there, mate. > > > > > On Tue, Dec 30, 2008 at 11:35 AM, Pat > > > > <[email protected]>wrote: > > > > > > On 30 Dec, 02:15, "Chris Jenkins" <[email protected]> wrote: > > > > > > Having a fuckload of babies certainly ups the chances, mate... ;) > > > > > > Isn't ANY load of babies, technically, a fuckload, though? ;-) > > > > > > > On Mon, Dec 29, 2008 at 8:53 PM, chazwin <[email protected]> > > > > > > wrote: > > > > > > > > On Dec 29, 4:45 am, "Chris Jenkins" <[email protected]> > > > > > > > wrote: > > > > > > > > Survival of the fittest is indeed commonly misunderstood, most > > > > > especially > > > > > > > > when it comes to humans. It's not survival of those most fit to > > > > > survive. > > > > > > > > It's survival of those most likely to procreate, and so it has > > > > > > > > been > > > > > > > through > > > > > > > > out all of evolution. > > > > > > > > Actually it is those who are able to produce successful offspring > > > > > > > in > > > > > > > their given environment. > > > > > > > Procreation is not enough in itself. > > > > > > > > > And so it is that those with nought else to do but rock the > > > > > > > > bedposts > > > > > turn > > > > > > > > out children at three times the rate... ;) > > > > > > > > > On Sun, Dec 28, 2008 at 11:30 PM, archytas > > > > > > > > <[email protected]> > > > > > > > wrote: > > > > > > > > > > The phrase "survival of fittest" is widely misunderstood Many > > > > > wrongly > > > > > > > > > assume it means that evolution always increases the chances > > > > > > > > > of a > > > > > > > > > species surviving. Evolution sometimes results in > > > > > > > > > individuals or > > > > > > > > > populations becoming less fit and may occasionally even lead > > > > > > > > > to > > > > > > > > > extinction. > > > > > > > > > > There are several ways in which evolution can reduce the > > > > > > > > > overall > > > > > > > > > fitness of individuals or of populations. For starters, > > > > > > > > > natural > > > > > > > > > selection can take place at different levels - genes, > > > > > > > > > individuals, > > > > > > > > > groups - and what promotes the survival of a gene does not > > > > > necessarily > > > > > > > > > increase the fitness of the individuals carrying it, or of > > > > > > > > > groups > > > > > of > > > > > > > > > these individuals. > > > > > > > > > > For example, parasitic DNA elements, or transposons, can > > > > > > > > > spread > > > > > > > > > through a population even though they make their host > > > > > > > > > organisms > > > > > less > > > > > > > > > fit. Transposons are one cause of genetic diseases such as > > > > > > > > > haemophilia. > > > > > > > > > > Similarly, selfish individuals may thrive at the expense of > > > > > altruistic > > > > > > > > > individuals in a group - making them the "fittest" - even > > > > > > > > > though > > > > > they > > > > > > > > > make the group as a whole less competitive. Such cheaters can > > > > > > > > > have > > > > > > > > > disastrous consequences. > > > > > > > > > > In 1932, J. B. S. Haldane suggested this could even lead to > > > > > > > > > the > > > > > > > > > extinction of populations - a phenomenon called evolutionary > > > > > suicide. > > > > > > > > > Models and some experimental evidence suggest he was right. > > > > > > > > > > For instance, when nutrients run low, individual myxobacteria > > > > > (slime > > > > > > > > > bacteria) may come together to form a fruiting body to produce > > > > > spores. > > > > > > > > > Lab studies have shown that cheating myxobacteria that only > > > > > > > > > produce > > > > > > > > > spores and never help form the non-spore producing parts of > > > > > > > > > the > > > > > > > > > fruiting body can drive populations to extinction. > > > > > > > > > > Genes capable of driving populations to extinction might have > > > > > > > > > a > > > > > > > > > practical use, however. Biologists are exploring the > > > > > > > > > possibility of > > > > > > > > > releasing engineered parasitic DNA into populations of > > > > > > > > > malaria- > > > > > > > > > carrying mosquitoes. > > > > > > > > > > There is concern that something similar could happen > > > > > > > > > accidentally. > > > > > > > > > Fish that have been genetically modified to produce a growth > > > > > hormone > > > > > > > > > grow faster and larger, mature earlier and produce more eggs. > > > > > > > > > But > > > > > they > > > > > > > > > are less likely to survive in the wild than unmodified fish. > > > > > According > > > > > > > > > to the Trojan gene hypothesis, a gene variant that produces > > > > > > > > > such > > > > > > > > > characteristics could spread rapidly through a wild population > > > > > despite > > > > > > > > > reducing individual fitness, and eventually drive the > > > > > > > > > population to > > > > > > > > > extinction. > > > > > > > > > > Another way in which evolution can reduce a species' chances > > > > > > > > > of > > > > > > > > > survival is through the accumulation of detrimental mutations. > > > > > > > > > Mutations provide the vital raw material for natural > > > > > > > > > selection, so > > > > > if > > > > > > > > > the mutation rate is too low a population will not be able to > > > > > evolve > > > > > > > > > fast enough to keep up with environmental changes. > > > > > > > > > > If, on the other hand, a population's mutation rate is too > > > > > > > > > high, > > > > > > > > > detrimental mutations may accumulate faster than natural > > > > > > > > > selection > > > > > can > > > > > > > > > eliminate them. Eventually, the number of mutations can > > > > > > > > > exceed the > > > > > > > > > "error catastrophe threshold", again leading to the > > > > > > > > > extinction of a > > > > > > > > > population. > > > > > > > > > > In theory, any species with a very small population could > > > > > accumulate > > > > > > > > > deleterious mutations faster than it can eliminate them. The > > > > > problem > > > > > > > > > is especially severe for asexual organisms such as the Amazon > > > > > > > > > molly > > > > > - > > > > > > > > > an effect known as Muller's rachet. > > > > > > > > > > It is far less of a problem for sexually reproducing species > > > > > because > > > > > > > > > the exchange of genetic material between chromosomes can > > > > > > > > > separate > > > > > good > > > > > > > > > and bad mutations. Some unlucky offspring get saddled with > > > > > > > > > lots of > > > > > > > > > nasty mutations and die out, while the lucky ones get hardly > > > > > > > > > any. > > > > > > > > > > In theory, a mutation catastrophe can also occur as a result > > > > > > > > > of > > > > > > > > > linkage. This refers to gene variants that are inherited > > > > > > > > > together > > > > > > > > > because they sit next to each other on a chromosome. Suppose a > > > > > > > > > mutation that greatly increases the mutation rate somehow > > > > > > > > > ends up > > > > > next > > > > > > > > > to a new mutation that greatly increases fitness. The > > > > > > > > > immediate > > > > > > > > > fitness benefits of the beneficial mutation will initially > > > > > > > > > mask the > > > > > > > > > deleterious effects of the "mutator" mutation, meaning both > > > > > mutations > > > > > > > > > will rapidly sweep through a population, ultimately with > > > > > > > > > disastrous > > > > > > > > > consequences. > > > > > > > > > > A few doctors hope to exploit mutation accumulation to treat > > > > > diseases. > > > > > > > > > Certain viruses such as HIV are already close to the error > > > > > catastrophe > > > > > > > > > threshold. Drugs that increase the mutation rate of the > > > > > > > > > viruses > > > > > still > > > > > > > > > further might push them over the threshold and drive a > > > > > > > > > population > > > > > of > > > > > > > > > viruses inside a person's body to extinction. > > > > > > > > > > Finallly, it has long been recognised that the competition > > > > > > > > > between > > > > > > > > > members of the same species to reproduce - sexual selection - > > > > > > > > > can > > > > > > > > > favour traits that reduce a species' overall fitness. Male > > > > > > > > > peacocks > > > > > > > > > with the biggest and brightest tails might get the females' > > > > > attention, > > > > > > > > > but lugging around a heavy, conspicuous tail reduces their > > > > > > > > > chances > > > > > of > > > > > > > > > survival. > > > > > > > > > > Studies of threatened bird species suggest that sexual > > > > > > > > > selection > > > > > can > > > > > > > > > indeed drive populations to extinction. Some biologists go so > > > > > > > > > far > > > > > as > > > > > > > > > to blame sexual selection for the conspicuous consumption that > > > > > > > > > threatens humanity's future. > > > > > > > > > > According to the handicap principle, features such as > > > > > > > > > peacocks' > > > > > tails > > > > > > > > > evolve precisely because they are disadvantageous. Consider an > > > > > > > > > individual who is trying to signal to females how fit and > > > > > > > > > strong he > > > > > > > > > is. If the signal is easy to make, weaker males can easily > > > > > > > > > cheat by > > > > > > > > > making the same signal. But if making the signal is costly - > > > > > > > > > such > > > > > as > > > > > > > > > growing a large, clumsy tail or giving away food - there's no > > > > > > > > > way > > > > > to > > > > > > > > > cheat. > > > > > > > > > > Proving that any of these phenomena have ever led to > > > > > > > > > extinctions in > > > > > > > > > the wild is far from easy, because any species to which this > > > > > > > > > has > > > > > > > > > happened are, of course, no longer around to study. The > > > > > > > > > indirect > > > > > > > > > evidence is growing ever stronger, though. > > > > > > > > > > The above is from this week's New Scientist. I've come > > > > > > > > > across > > > > > about > > > > > > > > > 20 misconceptions of evolution reading literature recently > > > > > > > > > and, of > > > > > > > > > course, creationist myths are legion. My interest is > > > > > > > > > indirect - > > > > > I'm > > > > > > > > > looking for examples of why our debates are so little evidence > > > > > based > > > > > > > > > for a theory of language.- Hide quoted text - > > > > > > > - Show quoted text -- Hide quoted text - > > - Show quoted text - --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups ""Minds Eye"" group. To post to this group, send email to [email protected] To unsubscribe from this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/Minds-Eye?hl=en -~----------~----~----~----~------~----~------~--~---
