Evolution, yes but how?

[The Dread Pirate]

We aren't really evolving in a physical sense any more due to the fact we aren't adapting to the environment but rather using technology to adapt the environment to suit our needs eventually we may start to use technology to improve our physical states but until then our evolution is advanced through knowledge rather than physical changes.

 

[Mr Jack]

We aren't really evolving in a physical sense any more due to the fact we aren't adapting to the environment but rather using technology to adapt the environment to suit our needs eventually we may start to use technology to improve our physical states but until then our evolution is advanced through knowledge rather than physical changes.

Yeah, that just doesn't follow.

The term 'survival of the fittest' does sum up evolution quite nicely but you need to understand what fitness is in the evolutionary sense. It doesn't mean 'strong', 'healthy', 'fast' or any other such trait we might subjectively view as positive. The best definition of fitness in an evolutionary sense is the number of grandchildren an organism has.

That's it. An organism is fitter than another organism if it manages to have more offspring and have those offspring survive to breed themselves. By extension a gene is fitter if it produces changes that contribute to an increase in offspring surviving to breed themselves.

The term environment too is frequently misunderstood. It does not simply refer to the physical environment but also to all the other species you interact with and all the members of your own species you interact with. It is most certainly the case that differences in that environment are altering the fitness of our genes. It is highly likely, for example, that there will be a strong selective pressure in Africa for genes that protect against HIV (e.g. the CCR5Δ32 mutation).

In our own culture genes that were once negative can now persist because modern medicine has reduced their effect on survival and fecundity.

Evolution will always happen. Nothing can't stop it.

Even if all genes had exactly the same fitness, there would still be evolution because random chance would alter the frequency of genes within the population - genetic drift.

 

[Mr Jack]

It has been proven that being a murderer ISNT genetic...

Really? Citation needed!

...HOWEVER there has been studies done which have found some males with XXY gene (which is supposed to be XY if you didnt know).

I think you mean XYY. Which isn't a gene, it's a karyotype. Human males should carry one copy of the X chromosome (which codes for many genes) and one copy of the Y chromosome (which codes for a handful). Males with an additional copy of the Y chromosome (who are XYY) exhibit "hyper-male" traits including increased aggression.

However, the karyotype is not heritable*. Being XYY does not mean you will produce sons who are XYY, instead they will produce normal (i.e. X or Y carrying rather than YY, XX or XY carrying) sperm with lower frequency (and thus lower fertility) and thus normal offspring.

* - this is not strictly true as karyotypic differences can occur with higher frequency due to faults in the meotic pathway and so there could be other genes carried by the XYY individual that increase the chances of more XYY offspring but the karyotype itself is not heritable.

 

[The Dread Pirate]

Yeah, that just doesn't follow.

The term 'survival of the fittest' does sum up evolution quite nicely but you need to understand what fitness is in the evolutionary sense. It doesn't mean 'strong', 'healthy', 'fast' or any other such trait we might subjectively view as positive. The best definition of fitness in an evolutionary sense is the number of grandchildren an organism has.

That's it. An organism is fitter than another organism if it manages to have more offspring and have those offspring survive to breed themselves. By extension a gene is fitter if it produces changes that contribute to an increase in offspring surviving to breed themselves.

The term environment too is frequently misunderstood. It does not simply refer to the physical environment but also to all the other species you interact with and all the members of your own species you interact with. It is most certainly the case that differences in that environment are altering the fitness of our genes. It is highly likely, for example, that there will be a strong selective pressure in Africa for genes that protect against HIV (e.g. the CCR5Δ32 mutation).

In our own culture genes that were once negative can now persist because modern medicine has reduced their effect on survival and fecundity.

Evolution will always happen. Nothing can't stop it.

Even if all genes had exactly the same fitness, there would still be evolution because random chance would alter the frequency of genes within the population - genetic drift.

I'm just saying that physically you'll notice little evolutionary changes compared to technological changes where we used to have to adapt according to the environment our hubiris has opened new evolutionary paths to us by allowing us not to just change ourselves but the environment around us to a greater extent than we ever could before e.g our decendants with much less knowledge and mental capacity than we currently have had a less significant impact oin the environment around them than we do now that our klnowledge has reached the extent it has I'm not saying physical evolution has stopped but it has generally slowed due to other evolutionary paths we've unlocked.

 

[Nitefly]

Isn't our latest evolution height? As in the human race is getting taller and taller?

Or am I speaking out of my arse?

You are right. Height is being selected for, at least in men (being tall is a sexual signal).

 

[Mr Jack]

You are right. Height is being selected for, at least in men (being tall is a sexual signal).

Is there any evidence tall men have more offspring?

 

[Nitefly]

Is there any evidence tall men have more offspring?

I find that a bit of a confusing request!

First, how many children they have is irrelevant, what matters is that those children continue to be sexually successful. Second, all you need to demonstrate that height is being selected for (in western society at least) is by demonstrating a preference amongst women for taller men as opposed to shorter ones.

 

[Mr Jack]

First, how many children they have is irrelevant, what matters is that those children continue to be sexually successful.

Um, no. If tall men on average have 1.9 children then tall genes will be slowly selected out of existence regardless of whether those children are themselves sexually successful.

Second, all you need to demonstrate that height is being selected for (in western society at least) is by demonstrating a preference amongst women for taller men as opposed to shorter ones.

No, that's not sufficient. It would be sufficient if there were a notable shortage of mates, or men typically took multiple reproductive partners, but it's insufficient in the case of humans.

You need to show not only that women are more attracted to tall man but that this difference leads to a difference in the fitness of the tall men. Fitness is best defined as the number of grandchildren, but it's usual to accept number of children as a sufficiently good alternative measure since the two correlate well under normal circumstances. Which is why I asked the question I did.

I see little reason to think that the people in our society who get the more desirable partners are going on to have the most children. If anything smaller families would appear to be more common among those at the higher end of the desirability scale.

 

[Nitefly]

Um, no. If tall men on average have 1.9 children then tall genes will be slowly selected out of existence regardless of whether those children are themselves sexually successful.

No, that's not sufficient. It would be sufficient if there were a notable shortage of mates, or men typically took multiple reproductive partners, but it's insufficient in the case of humans.

You need to show not only that women are more attracted to tall man but that this difference leads to a difference in the fitness of the tall men. Fitness is best defined as the number of grandchildren, but it's usual to accept number of children as a sufficiently good alternative measure since the two correlate well under normal circumstances. Which is why I asked the question I did.

I see little reason to think that the people in our society who get the more desirable partners are going on to have the most children. If anything smaller families would appear to be more common among those at the higher end of the desirability scale.

You're short, aren't you?

Joking aside, I don't really follow your train of thought. It is difficult to reply in depth on a smart phone, but in short your selection of number of grandchildren is not a suitable definition of fitness in this scenario. More apt would be the attractiveness of those grandchildren - in western human society monogamy reigns king, having more relatively more children is generally not desirable or wanted, so we see families with commonly 2-3 children. A higher number of offspring is no longer being selected for.

What is more important is the propagation and maintainance of those genes that drive sexual attraction.

Two other examples of sexual selection are larger breast size in woman and the abundance of blonde hair, which are both selected for.

Humans have a far more complicated set of selection pressures than most animals as well a less oppressive set of pressures too.

 

[sniffy]

Yes but if looking at the Mirror or The Sun newspapers tells me anything is that any overweight ugly chav can have 10 children. So that doesn't count anymore

In terms of natural selection they are deemed fitter than say a middle class couple that has one child. The children of the fat ugly chav will probably go on to each have ten chav children and so on. Evolution is about an environment, species within that environment and variation within the species. Factors that make up the environment will favour certain variations of a species and consequently they go on to breed more. It's just unfortunate that we have created an environment that favours those that pop out more children than they have the means to support.

 

[Mr Jack]

You're short, aren't you?

6' 3.5" actually. The half is important!

Joking aside, I don't really follow your train of thought. It is difficult to reply in depth on a smart phone, but in short your selection of number of grandchildren is not a suitable definition of fitness in this scenario.

There's a vast body of literature on how to usefully define fitness. Average number of grandchildren is the most widely accepted as a good definition (although, in practice, number of children is used in experimental studies because it's more measurable) because it combines both fecundity and survival. Simply pumping out more kids won't increase fitness unless those kids survive themselves.

More apt would be the attractiveness of those grandchildren - in western human society monogamy reigns king, having more relatively more children is generally not desirable or wanted, so we see families with commonly 2-3 children. A higher number of offspring is no longer being selected for.

Dude, a higher number of offspring is always selected for. That's what evolution does. Cultural values like "attractiveness" will only get evolutionarily selected for if they result in a higher number of grandchildren.

Look at it this way: evolution is all about the number of copies of a gene that exist. The number of copies of a gene will only increase if the gene is producing an increase in the number of offspring, right? If a tall person and a short person have 2 children then there will be no change in the number of tall genes and short genes in the next generation. If they both have 3 children there will be an increase in the number of copies of tall and short genes in the next generation, but the proportion will remain constant (and thus there will be no evolutionary selective pressure for either). However, if the tall person has 3 children and the short person 2 children then there is a selective pressure for tall genes because the proportion of tall genes will increase in the population.

So, to demonstrate that height is being selected for you need to show that tall people - on average, obviously - have more children than short people.

(You also need to demonstrate that there is a genetic component, in general, but I think that's pretty well established for height)

 

[Nitefly]

It's difficult to reply on my smartphone, I will return later!

 

[MookJong]

How is the ability for us to laugh and find things humorous passed on genetically?

What use would this have amongst mammals?

 

[mmj_uk]

Evolutionary changes can happen in a single generation, check out this guy:
http://www.youtube.com/watch?v=qLziFMF4DHA

He was blind from age of 3 but he uses sonar to see, if the whole of humanity went blind for some reason tomorrow it would probably only take a few generations before the whole of humanity used this technique, those who didn't 'evolve' to see without use of their eyes would likely go extinct.

 

[Mr Jack]

Evolutionary changes can happen in a single generation, check out this guy:
http://www.youtube.com/watch?v=qLziFMF4DHA

He was blind from age of 3 but he uses sonar to see, if the whole of humanity went blind for some reason tomorrow it would probably only take a few generations before the whole of humanity used this technique, those who didn't 'evolve' to see without use of their eyes would likely go extinct.

That's not an evolutionary change; it's a taught skill.

 

[MookJong]

Evolutionary changes can happen in a single generation, check out this guy:
http://www.youtube.com/watch?v=qLziFMF4DHA

He was blind from age of 3 but he uses sonar to see, if the whole of humanity went blind for some reason tomorrow it would probably only take a few generations before the whole of humanity used this technique, those who didn't 'evolve' to see without use of their eyes would likely go extinct.

How is that evoloution? It's like saying if I play tennis then my children will be good at it.

 

[elmarko]

In terms of natural selection they are deemed fitter than say a middle class couple that has one child. The children of the fat ugly chav will probably go on to each have ten chav children and so on. Evolution is about an environment, species within that environment and variation within the species. Factors that make up the environment will favour certain variations of a species and consequently they go on to breed more. It's just unfortunate that we have created an environment that favours those that pop out more children than they have the means to support.

Evolution does not care what society likes.

If the environment rewarded "a fat lazy chav" by having 20 children - all of which went on to have 20 children that in it'self is a genetic success.

Evolution does not have a goal or a care, it could quite happily lead to our end or success.

 

[elmarko]

Evolutionary changes can happen in a single generation, check out this guy:
http://www.youtube.com/watch?v=qLziFMF4DHA

He was blind from age of 3 but he uses sonar to see, if the whole of humanity went blind for some reason tomorrow it would probably only take a few generations before the whole of humanity used this technique, those who didn't 'evolve' to see without use of their eyes would likely go extinct.

Learned =/ Evolved

 

[Liampope]

Is there any evidence tall men have more offspring?

Yes - the increase in average height over the last few hundred years, in wealthy countries at least. Enabled by reduced poverty and easy access to sufficient (even too much) food and improved medicine, and the driving selection pressure is the fact that on average, to put it simply, tall guys get laid easier. I'm a short-arse so of course hate this selection pressure (well i did until I got married ), but it's an obvious fact none the less.

 

[Participant]

Tall men do generally get more poon (subjective from my observations). Unless of course they're freakishly long giants like 5UB, in which case they never get laid.