From someone who studied Biology at college, evolution [http://en.wikipedia.org/wiki/Evolution] only takes effect when there is a allele [http://en.wikipedia.org/wiki/Allele] frequencies change over time, and unless there's some sort of virus that wipes out most of humanity or a natural disaster, the most likely thing that will cause human allele's to change in frequency is differential reproduction.
Thing is, most of the things people have mentioned do not effect how many kids and grand kids you have. If the trait you're talking about isn't going to give you more grand kids then another trait, then it isn't going to "evolve."
For instance, we might continue to get taller, if and only if, taller people have more grand kids on average than shorter people. That sort of thing.
Problem is these relationships aren't always simple. For instance, people with Blue eyes might have more grand kids on average than someone with brown eyes, but brown eyes are a dominant trait and will make it very hard for a population of humans to become universally blue eyed. Or, take my height example: there are physiological limits on body size. There have been humans who are 7+ feet tall, but they start having serious health issues. And then, something like height specifically, is effected not only by genes but by environment, diet and what not.
Personally, I doubt very much that we'll evolve much more, especially since we're hopefully moving into an age of increased education and social awareness, which usually translates to smaller family size.
skeliton112 said:
We could evolve a predisposition against cancer and other deseases. A predisposition to be better at business. A predisposition to be promiscuous. There are always more ways to evolve.
The only things that are going to cause us to evolve "biologically" are going to be things that effect our reproductive rates.
If people who were better at business, better at surviving cancer, or more promiscuous had more kids---or specifically, had more grand kids---then that might be a trait that evolves, sure.
But I think you'll find little correlation between number of grand children and business sense, or if you do,you'll find a negative correlation.
I know for a fact you won't find people who are more resistant to cancer having more grand children, since most cancers set on past when most people reproduce. Therefore, cancer has a negligible impact on human reproduction. Maybe an immunity to testicular cancer or breast cancer which might set in before people reproduce, but that's a bit of a stretch.
The predisposition to promiscuity is an interesting one, except in an age of contraception and social awareness, I don't think many promiscuous people are popping babies out. This would also have to be an inheritable trait, and your kids would have to survive long enough to reproduce and pass it on themselves.
GrungyMunchy said:
Sleekit said:
and i suppose eventually someone will be born without an appendix.
You do realise that the appendix actually has a function right?
Function aside, the appendix does not effect how well you reproduce, it won't get passed on. True, someone might be born without one, and they might even have kids without one. But for the human species to evolve, that trait would have to become widespread in the population.
Again, unless there's some sort of disaster and half the surviving humans are of the no-appendix variety, I doubt we will evolve past the appendix.
Tinybear said:
The human race is devolving in the modern world, and evolving in developing countries. Take bad eyesight for instance. How many do you think has that problem in Africa? They have better disease immunity, some places even have a large part of the population with AIDS immunity.
Evolution happens because only those fit to live survive. In the western world, we keep everyone alive with technology. The natural system is overruled and unfit genes survive.
There is one "evolution" that the western world does have, and that is when the smart marry the smart, and get smart offspring. That is the only notable part of humanity that evolves on our part, the problem is that it's a select group, and might even end up making the differences huge in the future.
Devolving isn't a biological term. I suppose if you mean that negative traits are being removed from the population by differential survival and differential reproduction then... yeah. Course, I wouldn't really count this as a bad thing. I'd rather have to wear glasses (like I do) then get eaten by the lions and shit I couldn't see.
I'd be interested to see if people in the developing world are less likely to be near of farsighted. To my knowledge, the rate is exactly the same. Besides, since people in the developing world are dying of starvation, preventable illness and pollution, I'd be surprised that having better eye sight would allow them to have more kids.
The only additional disease resistance that I am aware of is Malaria [http://en.wikipedia.org/wiki/Malaria] resistance, which is a trait linked to Sickle Cell disease [http://en.wikipedia.org/wiki/Sickle-cell_disease]. I'd rather worry about malaria, personally.
Dominic Burchnall said:
So, do you think that, from the economic divide between First and Third world areas, two separate sub-species of humanity might evlove? (P.S. I'm studying genetics, so I know that any organism will develop a divide between species if separated by say a geographical event, but could the same thing come about today, in an age of easy long-distance travel, and would it happen before technological advances could be shared that would allow developing countries to catch up to us?)
No. We would need to be completely isolated for millions of years. Since that isn't the case now (there's a lot of legal and illegal immigrations between countries), and probably won't be the case in the future, it won't happen.
The developing world doesn't need to catch up technologically. Interbreeding between the developed and developing world already exists on a scale sufficient to prevent isolation. Think about this: for the millions of years that human populations were isolated from one another in Africa, Asia, Australia, Europe and the Americas, we still didn't split into multiple species.