Evolutions failures
Discussion
Matthew-TMM said:
Derek Smith said:
My colour blindness was mentioned in a biology lesson, someone suggesting that I should have died out long ago. I'd said that half the males in my family are/were partially colour blind as well. The teacher said that it must confer an advantage in some ways. He suggested that as the ice age was so recent it might have something to do with snow. Global warming is a bit of an irritation to me.
However, I do have good night vision. I used to cycle across the Downs at night - to and from work - and I could see perfectly well in 1/4 moonlight. A work colleague who said he'd have a go couldn't see a thing.
I used to enjoy unlit cycling over the Downs, having peripheral vision and seeing further ahead beats a bright light any day. Dad and I cycled from Woodingdean to Lewes one bonfire night, Dad had to use his light as he couldn't see a thing without it, though he does wear glasses which I'm told aren't so helpful in poor light. I was told at school (suddenly seems a while ago now!) that blue eyes are good for night vision but sensitive to bright lighting, while brown eyes aren't so good at night but better for bright light, how true this is I don't know.However, I do have good night vision. I used to cycle across the Downs at night - to and from work - and I could see perfectly well in 1/4 moonlight. A work colleague who said he'd have a go couldn't see a thing.
Interestingly the colour balance is slightly different between my eyes, the left one seems slightly better for red, orange and yellow while the right one is better for green and blue. Why is that I wonder?
I used to cycle at night and had three lights at the front of my bike, one of which I put on the back after changing the lens to red. It was apparent that I had good night vision. Mind you, I rode into the side of a cow once that I hadn't seen so perhaps not as good as I thought.
fadeaway said:
That's not how it works. Pen Hens have a preference for plumage and so selected males with the best plumage with which to mate. Males with better plumage therefore tend to father more offspring, and so their genes become more common within the populate. Often the characterist that females have a preference for is actually tied to another apparently unrelated characteristic which happens to be linked to the gene for great plumage.
I think that’s a great evolutionary failure right there. Peahens like big tails......big tails are harder to carry around, making the individual male peacock a much easier catch for predators and cost energy to carry, grow and maintain.
Without the tail the male gets no sex, so the males grow a tail, become physically less efficient at everything other than attracting females, get eaten more often than in necessary, but gets to pass on his genes.
The female on the other hand just stays smaller, brown, harder to catch and with less energy expenditure because she just has to accept mates, not attract or persuade them.
Clearly, Peahens clearly became unionised a long time ago.
Simpo Two said:
BIANCO said:
Eyes are a good example they have deteriorated over time so we invented glasses, contact lenses and now laser surgery.
Human lifespan is now far greater than it was supposed to be - our body is basically designed to run at decent speed for 35-40 years (ie long enough to bring up children), then die from something.LordGrover said:
Not too sure that's right. Average life expectancy was low in prehistory/palaeolithic times but that was largely down to high infant mortality, microbes that we now have protection/cure for, accidents, etc. Assuming all the above were avoided they likely lived a strong, healthy life certainly into their sixties and sometime seventies. Typically stronger and as intelligent as we are too.
Average life expectancy has doubled over the last 160 years or so. Even before that it was rising. Edited by TheHeretic on Thursday 21st February 16:35
LordGrover said:
Not too sure that's right. Average life expectancy was low in prehistory/palaeolithic times but that was largely down to high infant mortality, microbes that we now have protection/cure for, accidents, etc. Assuming all the above were avoided they likely lived a strong, healthy life certainly into their sixties and sometime seventies. Typically stronger and as intelligent as we are too.
But the point is that relatively few would live much beyond 30, and the women would stop having babies at 40 or so at best. So there was little evolutionary pressure to survive beyond that, even if there was a group that lived to 100+ there wouldn't be an evolutionary advantage unless they were able to have kids much later. Presumably grannies come in handy to help children survive but that's about it.Perhaps if we all stopped having children before the age of 30 human longevity would increase after a while. Or if only people with at least two grandparents living to 90+ reproduced.
Dr Jekyll said:
LordGrover said:
.
But the point is that relatively few would live much beyond 30, and the women would stop having babies at 40 or so at best. So there was little evolutionary pressure to survive beyond that, even if there was a group that lived to 100+ there wouldn't be an evolutionary advantage unless they were able to have kids much later. Presumably grannies come in handy to help children survive but that's about it.. .
Once you stop having kids you can still have a genetic advantage if your sticking around means your genes get passed on through your kids, or even via a brother or sister who share some of your genetic mateial.
That's why drone bees and worker ants dont just wander off. By working for the queen, they help a portion of their genetic code continue even if they never have kids.
Liokault said:
Dr Jekyll said:
LordGrover said:
.
But the point is that relatively few would live much beyond 30, and the women would stop having babies at 40 or so at best. So there was little evolutionary pressure to survive beyond that, even if there was a group that lived to 100+ there wouldn't be an evolutionary advantage unless they were able to have kids much later. Presumably grannies come in handy to help children survive but that's about it.. .
Once you stop having kids you can still have a genetic advantage if your sticking around means your genes get passed on through your kids, or even via a brother or sister who share some of your genetic mateial.
That's why drone bees and worker ants dont just wander off. By working for the queen, they help a portion of their genetic code continue even if they never have kids.
TheHeretic said:
Derek Smith said:
Re: peacocks:
The title of the thread is a little ironic. Can evolution have failures?
Yes. The extinct critters. They evolved, but went the wrong way.The title of the thread is a little ironic. Can evolution have failures?
On top of that, has evolution got targets? If not then how do we know that it failed?
Derek Smith said:
But that would make dinosaurs, one of the most successful bunch of critters, a failure, yet by any measure they were a success for some weeks I believe.
On top of that, has evolution got targets? If not then how do we know that it failed?
No targets. It has no goal. It is simply what is best for that time. Agree about failure, but I would put 'failure' down as a critter that was not adaptable, and thus an evolutionary dead end. On top of that, has evolution got targets? If not then how do we know that it failed?
LordGrover said:
Not too sure that's right. Average life expectancy was low in prehistory/palaeolithic times but that was largely down to high infant mortality, microbes that we now have protection/cure for, accidents, etc.
There are plenty of things to kill Mr Caveman after childhood - a simple infected wound would do the trick nicely. Dental records show that by about 35 their teeth were shot - without teeth you can't eat; you die. With no ability to farm or store food you're wide open to seasonal changes for food/water supplies. Derek Smith said:
But that would make dinosaurs, one of the most successful bunch of critters, a failure, yet by any measure they were a success for some weeks I believe.
Indeed; they were killed off because their environment changed faster than they could adapt to - they didn't have the gene for asteroids 
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