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you certain about this?
Even with selective breeding we have not achieved this goal yet with cows
No, I just made it up 😆 . They produce for just under a year apparently. Produce a calf, have a BBQ and a years worth of milk. Pretty handy thing to be able to do food-wise.
You backed down too easily, 5thElefant! 🙂
I'd suggest talking about human milk nurses, who carry on producing milk for as long as a baby, any baby, is suckling.....
Although pregnant Mrs IJ says it's not always the case unless you can see your own baby, or even a photo of your baby! Who knows? Not me!
IdleJon - Member
It is - but completely irrelevant in terms of the question posed by Horizon. 'Have humans stopped evolving?' It is a bit of a sideshow, like the worms on Dartmoor. Interesting, but why are we looking at worms?
i think it's completely relevant, it's an excellent demonstration that even small selective pressures will result in genetic adaptations becoming widespread over time.
there must be many selective pressures acting upon us today that we're not even fully aware of.
smoking, drinking, eating red meat, etc. are all known risk factors for cancer.
cancer, generally, is a bad thing, it often ends up with death. dead people don't breed = selective pressure = evolution.
'we' have treatments for cancer here in our rich country, but it's not 100% successful, and many billions of people don't have it.
the leading cause of death for young males in our country is from car crashes. are nob-head drivers being removed from the gene-pool?
lactose intolerance is not a terminal condition, but even so, it's evolutionary pressure is obvious.
it's a brilliant example to use.
lots of population groups + lots of factors = a completely unpredictable evolutionary present/future.
have we stopped evolving? - not even a little bit.
IdleJon, I assume that the population studies were done by competent statisticians. Why don't you chase up the original article and answer your own question? Then present a reasoned criticism.
cancer, generally, is a bad thing, it often ends up with death. dead people don't breed = selective pressure = evolution
Except that cancer usually strikes after you've passed on your genes. Hence cancer risk being hereditary.
Anyway, I was thinking - females seem (on the whole) to have evolved a maternal instinct to make them want kids and hence perpetuate genes. Men seem to have evolved a desire to shag whatever they can, which is also good at perpetuating genes. However, now casual sex doesn't necessarily result in babies due to contraception, so if you don't want to settle down and have kids it's no longer a bi-product of testosterone fuelled womanising.
Therefore there'd be a higher proportion of kids born to fathers who actually want to be fathers.. thereby evolving a prevalence of 'paternal instinct' to match the female one... But if a paternal instinct is linked to some other factor like say lower testosterone, we would also be breeding in ourselves lower levels of aggression, as someone mentioned earlier in the thread.
Purely a hypothesis here - please excuse me for being sexist/generalist.
have we stopped evolving? - not even a little bit
Unless we never evolved in the first place...
most of us knew you were generally sexist anyway 😉
Did someone mention a bus sized hole? I'm still looking....
Whilst on the subject of buses I think I may be evolved to be very attuned to the sound of busses approaching from the rear which actually stopped me being squished against some railings last night. Didn't get a chance to pass on my 'genes' though as she was tired.
ahwiles, I still disagree!
[i]i think it's completely relevant, it's an excellent demonstration that even small selective pressures will result in genetic adaptations becoming widespread over time.[/i]
In terms of the question posed by Horizon, 'Are we still evolving', it is just an example of how we evolved in the past, so the only relevance is that we have evolved.
In your very next line:
[i]there must be many selective pressures acting upon us today that we're not even fully aware of.
[/i]
you ask exactly the question that Horizon should have been asking, and only addressed in passing when talking about the gene pool being weakened by childhood survival rates.
Perhaps Horizon should have asked the question, 'How have humans evolved over the last 10,000 years?', because of course we are still evolving.
Moses, telling me to go and find the original research paper is a cop-out. I watched Horizon to learn something and came away feeling rather short changed. If you have a scientific background of any sort, you must see that analysing data on height for 60 years, just 3 generations, is going to give no answers about evolution.
Interestingly the first info I can find on the net about height change in the US backs up my gut feeling.
[i] The decline in their height is most likely related to the obesity epidemic caused by inadequate dietary balance.[/i]
But, what I'm trying to get across to you is that if you look at a populations' height for 60 years, that is NOT conclusive proof of anything. My father (born 1947) is 6ft2", I am 5ft11" (b.1968), my kids are likely to be tall but maybe not over average height. 60 years of data! There will always be a variation. (A very unscientific example!)
If you published a paper describing how fruit flies had evolved after 3 generations (about 1 week?) I have a feeling you'd be laughed at.
Just because something is presented in TV as SCIENCE doesn't mean that you don't need to think about it.
IdleJon, I do know something about science, thanks.
I spent a happy half-hour this morning chatting to a pharmacogeneticist.
I know enough to understand that 3 generations is plenty of time to determine whether a population is changing (ie is evolving, as per the programme title), if you have a town-sized sample.
Referring to the original document is NOT a cop-out, it's asking you to educate yourself about the methodology before criticizing it.