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Human Evolution: Not Complete?

 
 
farmerman
 
  2  
Reply Sat 22 Aug, 2015 04:31 pm
@Finn dAbuzz,
We really dont know how much of evolution is due to gene transfer and how much is natural selection. We think that most (>90%) is nat selection but thats an unfolding story .
0 Replies
 
jespah
 
  2  
Reply Sat 22 Aug, 2015 06:36 pm
@Finn dAbuzz,
Finn dAbuzz wrote:

...

I have a difficult time understanding though how a, let's call it a "neutral" mutation gets passed on enough to become common to the species in the absence of an "advantageous" mutation. ...



Maybe it's mate selection at work. If a smaller waist or a red beard or the like are somehow seen as 'attractive', then an individual possessing any or all of the more desirable qualities is going to have a better chance at finding a mating dance partner. Plus genes will come along for the ride on the chromosome (at times). If a predisposition to a metal allergy (a fairly neutral mutation, at least before the Industrial Revolution) is on a gene that's close to the gene for a smaller waist, then it's got a better chance of being inherited, yes?
0 Replies
 
Setanta
 
  1  
Reply Sat 22 Aug, 2015 06:41 pm
@Finn dAbuzz,
Survival of the fittest refers to the species, not the individual. Your super-strong individual's offspring won't enjoy an advantage if another species dominates the food sources of that environmental niche. They could accomplish this by being faster, being more reproductively prolific, having more acute eyesight or any of another of an array of traits. If the offspring of the super-strong individual do not compete successfully for the food source, another species may well prove to be the "fittest."

As an example, the short faced bear (Arctodus simus. Flourishing in North America from about 800,000 ybp to about 11,500 ybp, it was the largest carnivorous animal then living in North America--and certainly the strongest. It's limbs articulated so that it ran like a horse, opposite feet moving in concert. That meant, though, that a prey animal that dodged could probably easily evade it. At any event, it disappeared shortly after the arrival of h.s. in the Americas. Some say the simple explanation was that it was a victim of the Holocene extinction--i.e., those extinctions associated with the flourishing or arrival of h.s. Others think that brown bears and black bears may have proven more successful ursine predators, and simply squeezed Arctodus out. Certainly, brown and black bears survived when Arctodus didin't despite it's size and strength.

As for survival of the fittest, it refers to species, not individuals.
Setanta
 
  1  
Reply Sat 22 Aug, 2015 06:42 pm
By the way, as i've said here many times, we've removed our evolutionary environment from natural settings and placed it in libraries and universities.
Setanta
 
  1  
Reply Sat 22 Aug, 2015 07:18 pm
This survival of the fittest dodge is like the Whigs. As the range of their electoral popularity shrank, individual Whigs may have enjoyed public office, but the party was doomed.
farmerman
 
  1  
Reply Sat 22 Aug, 2015 09:00 pm
@Setanta,
Travel has mostly limited significant variability in gene expression. If ppopulations stay in an area in which they arose, the unique "markers" in the non-coding parts of the genome or as "glitches in the coding segments ' as well as epigenetics , will mark the uniqueness of those genomes of the population as a whole. As those folks choose to migrate (either by opportunity, war, or other reasons), we slowly get "Homogenized" and all those accumulated markers get harder and harder to analyze, and are less able to impart a true phenotypic change (like if Sherpas would travel to San Diego , the differences in their"sherpa"(EPAS1) SNP's would be "blended" like Neanderthal genes in successive hundreds of generations.
farmerman
 
  2  
Reply Sat 22 Aug, 2015 09:03 pm
@farmerman,
anyway, evolution is a process (mindless and opportunistic), its not a goal
0 Replies
 
Finn dAbuzz
 
  1  
Reply Sun 23 Aug, 2015 12:07 pm
@Setanta,
I'm familiar with the "short faced bear" and it's presumed prowess. That it is extinct now obviously suggests that it's advantages, at some point, were no longer sufficiently advantageous. Whether this is because of a change in its environment, its prey sources or the presence of other species that could out compete it, I have no idea what-so-ever, but it was around for quite a long time.

"Survival of the fittest" may, in academic circles, apply to the species rather than the individual, but if individuals of a given species didn't possess advantageous genes which they could then promulgate within the species and transform it accordingly, the "transformed" species would not end up being deemed "the fittest" for any period of time. So it comes down to individual members of any given species having a reproductive advantage. What anyone wants to term this seems immaterial to me.

Unless there is a plausible theory that explains evolutionary changes within a given species and discounts entirely the presence of a mutation within one or more individuals of the species as a catalyst, I don't see the point or arguing species vs individual. There may very well be some theory such as this. I make no claim to being an expert on this subject. I am merely attempting to address the original question based on what I do know about evolution and basic logic.

0 Replies
 
Finn dAbuzz
 
  1  
Reply Sun 23 Aug, 2015 12:08 pm
@Setanta,
And I believe I have been saying essentially the same thing.
0 Replies
 
Setanta
 
  1  
Reply Sun 23 Aug, 2015 12:42 pm
My remarks were in response to a claim about survival of the fittest, which you insisted on repeating. We were not saying the same thing at all. I even made a little political joke about it . . . Nope, ziiiiiiing . . . right over your head. I don't know why I bother to try to talk to you.

Finn dAbuzz
 
  1  
Reply Sun 23 Aug, 2015 02:06 pm
@Setanta,
You know, I've never understood why you "bothered" to talk to me either.
farmerman
 
  1  
Reply Sun 23 Aug, 2015 02:47 pm
@Finn dAbuzz,
short faced bers were here via Asia in the early pleistocene . The short faced beqrs are related to the sun bears and pandas (WE HAVE a great deal of their DNA from frozen carcae)
Our other bears came via the overland route either Beringea or ice covered Arctica and arrived quite a bit later in mid Pleistocene.

Theres talk of cloning one of these critters.

So, any evolutionary significance of these things would have to go back to a common ancestor of pandas and sun bears back in the late Miocene to Pleiocene. Our recent "native" bears from cave bear stock ?(the common ancestor is a morphologically similar Ursus etruscus"Etruscan bear.

its neat we have all this DNA from species of about 25000 years and later
Finn dAbuzz
 
  1  
Reply Sun 23 Aug, 2015 03:01 pm
@farmerman,
So bear with me here (no pun intended), something led to the common ancestor of short faced bears, pandas, and sun bears "evolving" along at least these three separate paths. That there isn't a simple linear evolution of the first living cell to a single species (if such a things was even sustainable) is evidence that there are numerous different advantages/solutions to the "problem" of continuing to propagate. (And yes I understand that evolution is not an entity determined to solve a problem or meet some goal).

So somewhere back in prehistory the common ancestor species produced individuals with mutations that proved advantageous, in similar and different ways, to those that had them in terms of reproduction and the three different species evolved.

[It's hard to imagine that pandas would be a more successful species (over time) than the monstrous short face bear, but that's because I'm inclined to think that the big tough carnivore should be more successful than one that eats only a single plant. I understand though that this is just a sentimental preference for predators.]

If this is not a fair, albeit simplistic, rendition of what happened, please let me know and why.

Thanks

farmerman
 
  1  
Reply Sun 23 Aug, 2015 05:15 pm
@Finn dAbuzz,
Pandas always had an interesting tory an one in which I was forced to sit through boring lectures about the man who commited the big error of assigning Pandas to the family that includes raccoons and coati mundis and Pandas, They were stuck together because they looked alike. And, like other animals that have parallel adaptive morphologies, it was all fucked up.
The Chinese straightened it out in the last 15 years when they harvested DNA and compared it to all the DNA available (including the short faced bear). The split off of the short faced fambly an the true Ursus was late Pliocene and short faced bears are primarily a beast of N and S America (the giant panda was supposedly evolved through a "bottleneck" that responded to the large expanses of bamboo covered mountains that were much mire widespread in china in the early Pleistocene. The big argument now is whether the Giant panda is an evolutionary cul de sac. because its finely honed adaptive boundaries (mountainous, bamboo forest with seasonal temperature s). These conditions are quickly being winnowed away by humans. China has taken some drastic steps to stop their decline (its like a National SYmbol and people really care for the things).
So the giant panda an the short faced bear descended from a "smaller panda-like individual) that showed (apparently) severl pqths of genetic variation so that the red panda, the pnda, the giant panda, sun bear, short faced bear all owe their gret grandparent linkage to a small raccoon faced bear. (It was not anywhere related to a Procyon family member it was an Ursidae.

Our own bears were not anywhere related to short faced bears . They were more related to the European CAVE BEAR which was even bigger but, like the Panda, was a veggiemegafauna. The Mouterian Culture probably developed as a outgrowth of basing most of their necessities oin the cave bear. The cave bear was only firt described in the post WWI time when farmers were mining bat **** from caves for use as fertilizers since the big fertlizer plants were either burnt or converted to explosives manufcture. The dicovery of cave beqr fossils indicated that these guys died out around the same time as Neanderthals. (Why) its been speculated that , while they were being harvested by Neanderthals" , the climate change got decidedly colder and their major foodstuffs _grasses and low foliage) only grew for a few months so the beqrs spent a large part of the year hibernating and their teeth kept growing and this caused major dental hygiene problems (I am not making this up). Some of the cave beqrs extended their ranges north and over the ice and around Beringea.
The vegetarian bers again reoccupied their former carnivore status and evolved several lines of Ursus.
I only know this crap because of former seminars on paleogenetics at U Penn. (The Short Faced Bear, it turned out was first named in the 1800's by Joseph Leidy who wqs a pqleontologist at U Penn-so, in his memory Penn had some lectures and programs during the Darwin Birthday year in which their paleogenetics and geo and paleo programs did some interdisciplenary presentations on these very bears an the evolution of whole bunches of them.

Will the Giant Panda Die out??
I wouldnt bet against the eventuality


farmerman
 
  1  
Reply Sun 23 Aug, 2015 05:30 pm
@farmerman,
But your question i that although Pndas hd several bottlenecks involving food and temp, the short fced ber, because it had the femoral attachment just like terror birds , where running wasnt a problem, but turning on a dime was. So, its believed that short faced bears became opportunistic stealth hunters who often took prey from dire wolves and even smilodons. The largest herd of these bears was in the California Oregon areas.(They didnt have a huge rqnge so they too hd a "niche to which they were finely tuned and ultimately controlled"

California climate changed in the terminal Wisconsin period so the savannah/desert climate may have chased out prey animals and caused the demise of first level predators. Did the humans have anything to do with their demise? its always been a story to which guys like Wendt spoke
0 Replies
 
kk4mds
 
  1  
Reply Wed 31 May, 2017 10:13 am
@Finn dAbuzz,
“It is not the strongest of the species that survives, nor the most intelligent that survives. It is the one that is the most adaptable to change.” ~ Charles Darwin

In regards to human evolution, evolution is an on going process. However, with humans able to modify our environment, we may be interfering with the natural process. The ultimate effects are, of course, anybody's guess.

An apocalypse is not required for evolutionary change. Even the most subtle environmental change can cause adaptation. Even no change. Organisms may change to better survive in an existing environment.
Finn dAbuzz
 
  1  
Reply Mon 5 Jun, 2017 04:41 pm
@kk4mds,
Humans have reached the point where they can override evolution

It doesn't mean that evolution won't ever impact them but it does mean that we are far more in control of our destiny as a species.
newmoonnewmoon
 
  1  
Reply Mon 5 Jun, 2017 04:46 pm
@Student Ally,
Or what if we evolve into aliens
maxdancona
 
  1  
Reply Mon 5 Jun, 2017 05:09 pm

0 Replies
 
farmerman
 
  1  
Reply Mon 5 Jun, 2017 05:24 pm
@Finn dAbuzz,
Always remember Finnsy, nature bats last.

n extreme issue but relevant. suppose we ignore certain environmental signals such as continuing the ozone layer depletion, we open ourselves to cosmic radiation that perhaps our biology cannot handle by natural selection or even artificial selection.We can become the victims of our own density of population were there a particularly antibiotic resistant strain of (usually) bacteria. Or We could lose a huge portion of our population that (as seen in the Spanish flu), the largest proportion of deaths from the virus were seen in people with the strongest immune systems. (Autoimmune reactions are where the bodies own defenses "turn against you").





 

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