What evolutionary purpose does having large breasts serve?

Being mammals that walk on our hind legs, a woman's chest was brought more into view. If you look at apes, the chest is covered in hair. As with all mammals, the hair obscures the mammary glands (breasts). It is all a visual evolutionary process. When human nature allows, the normal routes for evolution are guided in a different path. By this, I mean nomadic humans didn't have huge breasts. It would have impeded the migration of our nomadic ancestors. But being able to evolve in cities, different choices were made, different evolutionary paths were followed.

1. Bigger breasts have more breast tissue in which milk can be produced, but in some women it is beyond necessary. Due to the loss of nomadic nature, evolutionary pressure was changed from the essential to what desired by social pressures.

2. No longer being nomads, running and city life are a bit divergent.

3. Distracting men in the city will bring more mates. More mating causes evolution.

4. When anything is involved in the social and sexual pressures in evolution, developing a social order and trying to climb it are all a part of evolution. Your large breasts cause you to be more attractive, therefore a competitor in a struggle for dominance and mating opportunities.

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Having Large Breasts

Breasts are what is called a "secondary sexual characteristic" - they are a biological signal that you are a sexually-mature individual, but they don't perform a *direct* role in reproduction themselves. Other examples include the decorative plumage of male birds, the mane on a lion, and the deepening voice of a boy going through puberty.

As you say, there are downsides to having large breasts (the same as there are, for example, for a peacock having its large tail). Many animals don't have large breasts - female dogs don't, and even female chimpanzees don't (theirs are small, but swell for a while when they have given birth), so there must obviously be *some* evolutionary advantage to them.

The answer is thought to be just that they can be used as a signal that you are sexually mature (and, possibly, available).

When we were more quadrupedal, like most apes still are, it was the buttocks of the females that were often large or decorated, and were used in displays of sexual readiness.

When we became bipedal, this was less of an option - so one theory is that the breasts swelled as "mimics" of the buttocks to demonstrate that you were sexually mature, and to be used in displays of sexual readiness.

This feature was enough of an advantage that it overcame the downsides you mention (though, to be fair, the "distracting working men" probably wasn't as much of an issue when men were hunters).

The whole reason evolution works is that there is constant and inevitable variation as a result of genetic mutations and errors of copying. This means there will always be big breasts and small breasts for no reason other than the fact that reproduction could never be a 100% error-free process, so the gene pool is full of different breast-building genes which build different sizes and shapes of breasts. This variation is the raw material of natural selection, i.e. evolution.

The only evolutionary purpose of breasts is as a mammary gland to produce milk and feed the offspring. Large breasts are no more effective than small ones.

Most men are attracted to large breasts. Therefore, a large-breasted woman would have a higher-than-average expected number of offspring. Surely you have noticed this attraction factor? Because it would be the height of naïveté to believe that most men care about personality, or any of these "defects" you listed... you're not diseased; don't worry about your body.

They don't serve any purpose other than attracting men with one track minds.EDIT Check out the spelling in the first answer.

Who cares about their purpose? Large breasts rule!!!

Sounds really interested