This is a reply to a post by Kleinman on the thread,
Subject: Mysteries of Evolution: Sexual Reproduction; Part A, meiosis
On Wednesday, June 5, 2019 at 10:15:03 AM UTC-4, Alan Kleinman MD PhD wrote:
> On Wednesday, June 5, 2019 at 6:45:03 AM UTC-7, Peter Nyikos wrote:
> > On Tuesday, June 4, 2019 at 10:00:02 PM UTC-4, Alan Kleinman MD PhD wrote:
> > > On Tuesday, June 4, 2019 at 6:45:02 PM UTC-7, Peter Nyikos wrote:
> > > > On Friday, May 31, 2019 at 12:40:03 PM UTC-4, Bob Casanova wrote:
> > > > > On Thu, 30 May 2019 18:57:23 -0700 (PDT), the following
> > > > > appeared in talk.origins, posted by Peter Nyikos
> > > > > <
nyik...@gmail.com>:
> > > > >
> > > > > >On Thursday, May 30, 2019 at 4:10:03 PM UTC-4, John Harshman wrote:
> > > >
> > > > > >> Egglaying and odd shoulder girdles
> > > > > >> would as easily be apomorphic as plesiomorphic, absent an outgroup to
> > > > > >> root the characters.
> > > > > >
> > > > > >You've got to be kidding! getting from the shoulder girdle
> > > > > >of all other mammals to the one of monotremes is much harder
> > > > > >than the opposite direction. We AGREED that it is harder
> > > > > >to add new parts than to lose old parts.
> > > > >
> > > > > I suspect that would strongly depend on whether there was a
> > > > > strong negative selection pressure involved WRT the "old
> > > > > parts", and/or a strong positive selection pressure WRT the
> > > > > development of "new parts".
> > > >
> > > > I never thought I would see the day when you would
> > > > sound like Dr. Dr. Kleinman.
> >
> > > Get the wax out of your ears Professor [Nyikos]. Only dim bulbs would see selection pressures as positive or negative.
They are both. Below, you blunder by opting for them being
negative for EVERYONE
> > Bob was too much of a dimbulb to respond to this, so I will.
> > It is useful to think of any environmental factor that
> > increases the fitness of a variety as a positive selection
> > pressure.
> Has Professor [Nyikos} ever grown a garden? Is feeding your plants a positive selection pressure or is it simply removing starvation?
Is adequate heat a positive selection pressure for ectotherms or is it
simply removing of cold?
I opt for the former in both cases because the latter sounds
very strained AND because you are reading
the Wikipedia entry you linked in too simplistic a way.
You have failed to take into account its SECOND sentence:
With sufficient pressure, inherited traits that mitigate
its effects--even if they would be deleterious in other circumstances
--can become widely spread through a population.
IOW, the pressures can improve the fitness of the individuals with
those traits. Even absolutely and not just relatively, although
the entry only opts for a formula about relative fitness.
> If you want to improve fitness of a replicator, remove selection conditions.
Or add some to decrease the fitness of competitors. This is something
that would have prevented you from contradicting that second sentence:
> This allows the less fit variants to reproduce which couldn't under the previous selection conditions
Formerly less fit. And here comes the contradiction:
> and allows the more fit variants to reproduce in greater numbers.
If understanding that second sentence is beyond your pay grade,
look at what the entry you've linked below says about malaria.
<snip of things to be discussed in separate reply>
>
https://en.wikipedia.org/wiki/Evolutionary_pressure
Relevant excerpt:
The Malaria parasite can exert a selective pressure on populations.
This pressure has led to natural selection for erythrocytes carrying
the sickle cell hemoglobin gene mutation (Hb S) -- causing sickle cell
anaemia -- in areas where malaria is a major health concern,
because the condition grants some resistance to this infectious disease.
Note how it says the malaria parasite enhances the fitness of people with
sickle cell trait [even with the decrease in the homozygote due to
sickle cell anemia] at the same time it decreases the fitness
of those without it. It is positive for those with the
trait and negative for those without it.
<snip>
> > > > Won't [Kleinman] be proud. :-) :-)
> >
> > Hey, Bob made a step in your direction. Don't be a killjoy --
> > tell us all how proud you are of his accomplishment.
> If dimmy is looking for an ataboy, he needs to go back to his statistic text and read the introductory chapters on probability theory. Once he understands these chapters, then maybe he'll get something out of his statistics courses.
Killjoy.
Peter Nyikos
Professor, Dept. of Mathematics -- standard disclaimer--
University of South Carolina
http://people.math.sc.edu/nyikos/