To what extent are humans in a technological society exempt from natural selection?

[H.P.T Mobbster]

To what extent are humans in a technological society exempt from natural selection????

[Sayonara]

Not very.

 

The only thing that has really changed is that the range of factors affecting us has shifted.

 

For instance, on the whole we aren't advantaged by having highly developed predator-evasion adaptations, but on the other hand the less observant among us are more likely to be killed in avoidable "man-made" accidents (traffic accidents etc).

 

There are also far more discrete effects than in other species, such as highly complex, socially-mediated, peer-influenced courtship rituals and mate selection.

[H.P.T Mobbster]

Hmm.....Ok I understand some of what ur saying.For instance how the less observant in our society are the ones most likely to be killed , but what about the fact that natural selection can olny operate on the traits that nature can see"phenotype ect" since our species alters nature constantly how will natural selection or evoultion take place.The human race is constanly devoleping sciences and technolgies to evolve them/our-selves...???

[Sayonara]

How does our species alter nature constantly?

[H.P.T Mobbster]

For example deforestaion, highway, interstates, and other changes man makes to the world and or environment.We constantly change things that nautaly happen or occur in nature.

[Sayonara]

True, but natural selection can happen with or without outside influences.

 

And changing the environment simply changes the influences it has on us; so selective pressure is only shifted, not removed.

[VendingMenace]

sayo is 100% correct. We will never be free from natural selection -- it just cannot happen. What will happen is that the selective pressures change (as he pointed out). So now instead of selecting for people that can outrun a predator we are selecting for people that can drive well, or people that are resistant to environmental toxins that we introduce, or people that are able to play the corporate game.

 

Natural selectioin is not some self-aware entity that can be "foiled" it is simply a term used to describe how and why gene frequencies tend to favor one type of gene over another.

[Cap'n Refsmmat]

Natural selection = http://www.darwinawards.com

[-Demosthenes-]

Human's jaws have become smaller. Small jaws were found more attractive so more people with small jaws reprodiced and less with larger jaws.

[Sayonara]

-Demosthenes- said in post # :

Human's jaws have become smaller. Small jaws were found more attractive so more people with small jaws reprodiced and less with larger jaws.

Jaws are getting smaller because of changes in our diet and the way we prepare food.

 

When was the last time you heard a woman say "oh no, his jaw is far too manly. I prefer making babies with ladyboys."? Or did you just forget half the population are males?

[-Demosthenes-]

My biology teacher told me about it though. ??

 

How would our diet change it? People with bigger jaws will eat faster and have more time for...uh...reproduction?

[Sayonara]

-Demosthenes- said in post # :

My biology teacher told me about it though. ??

Ask him/her to point you in the direction of the relevant studies and see what happens.

 

How would our diet change it? People with bigger jaws will eat faster and have more time for...uh...reproduction?

Anything that's tough, we cook. We soften, tenderise, puree, mash, boil, steam or fry most of what we eat.

 

We don't need to grind up tough plant material to the extent that our distant ancestors did, nor do we need to tear or slice meat from the bone with our teeth - parts of our dental arrangement are now fully redundant (bye-bye wisdom teeth, we won't miss you).

 

In fact there was a time (Australopithecus through to Homo erectus) where we were eating so much more meat, and so much less vegetable matter, that our entire molar assmebly was virtually obsolete.

 

http://www.beyondveg.com/billings-t/comp-anat/comp-anat-6b.shtml

[Cap'n Refsmmat]

I'll miss my molars. It's kind of hard to eat when they hurt, so I can't imagine eating without them.

[Sayonara]

Apparently there are also the issues of space needed for increased brain cavity, and the requirements imposed by language.

 

These affect the overall shape of the oral system and the size of the buccal cavity rather than the lower jaw though.

[-Demosthenes-]

But it didn't make people die or unable to reproduce, our genes as a species would be unaffected. To affect it it would have to remove the people from the gene pool. It's almost vestigil, it dosn't seem like it would affect much.

[Sayonara]

Cap'n Refsmmat said in post # :

I'll miss my molars. It's kind of hard to eat when they hurt, so I can't imagine eating without them.

Unless you're planning to evolve by yourself I wouldn't worry about it.

 

However, painful molars is something to worry about. See a dentist.

[Cap'n Refsmmat]

No, the dentist did it to me. I suppose that's what he meant to do... I hate dentists!!!

[Sayonara]

Also I just remembered: we're currently eating thousands of times more simple sugars than we ever have done, which means we don't need to macerate our food so much to get the glucose we need.

 

Although, considering the number of obese people about these days, this seems to be an optional factor.

 

-Demosthenes- said in post # :

But it didn't make people die or unable to reproduce, our genes as a species would be unaffected. To affect it it would have to remove the people from the gene pool. It's almost vestigil, it dosn't seem like it would affect much.

It's a falacy to believe that only an advantageous macro-adaptation will be "selected for".

 

If there's no point in growing a particular pair of molars, or in having a jaw of size X, or having masseter muscles with strength Y, then there's not much point investing biomass in them.

Therefore individuals without that wasted investment will be utilising the currency of their ecosystem more efficiently.

[Cap'n Refsmmat]

And be able to reproduce more, which in turn starts spreading the new look! (or whatever you want to call it)

[-Demosthenes-]

Okay, I see how that would work

thanks Cap

[Sayonara]

Utilising currency more efficiently does not guarantee better reproductive success in terms of mating, but it decreases the chances of problematic pregnancies/deliveries etc, and is probably one of the possible keys to delivering genetically fitter offspring (unlikely to occur in one generational step).

[-Demosthenes-]

Thank you Sayonara. I didn't see that before.

COuld the other theory have some play in it??

[Sayonara]

If you mean a species-wide, transgender preference for smaller jaws, it's unlikely.

 

That kind of effect is usually highly localised in both time and space for humans, as the cultures we live in tell most people what to like, and when. We don't tend to do things in giant, like-minded groups.

[-Demosthenes-]

Darn, I guess she is a little to old to teach.

[Sayonara]

When I was at school they told us lies like that deliberately, because at that level it was easier than spending 5 days trying to explain it properly, and in context, when we had a syllabus to cover.

 

ESPECIALLY in bloody physics