It seems to me that every part of our wonderful body serves SOME purpose no matter how big or small. Why the difference in earlobes then? It would only make sense that there would be a difference if one was superior to the other. Is this the case? Also, is one type of earlobe more dominant than the other?
I remember reading (caveat-in a pop-medicine magazine) that there was a correlation between attached earlobes and blood sugar levels in expectant mothers. I have no idea why this might be the case.
Some real evolutionists will be along shortly and this may end up in GD, but this isn’t true. Traits get selected out only if they are detrimental to the organism. Earlobes are not.
It’s incorrect that every part of our body is functional. Genes are propagated if they help a creature survive, or pruned if they harm its survival. Genes that don’t matter a lick, such as free vs. attached ear lobes, either spread or disappear by random chance. IANAGeneticist, however.
I’d love to have a cite for that. I’m not saying it’s false, but I haven’t heard of it nor could I find it referenced on Medline.
There is though, possibly, a relationship between having diagonal ear lobe creases and having coronary disease. Here is a link. More recent studies have tended not to confirm the association.
As I said in another thread a long time ago:
KarlGauss, IIRC Mom read it in Prevention magazine, around 1980 or so. Considering the combination of the source and age of the citation it’s probably not worth looking for.
As mentioned, only those traits which are clearly detrimental will be selected against. Others will either impart some advantage, thereby increasing their representation in a population, or are selectively neutral, in which case their relative appearance in the population will likely be determined largely by chance.
In addition, not every morphological trait is directly the result of genetics. There’s a lot that happens during development which can likewise result in morphological differences. Since such traits are typically not, therefore, heritable, they are largely evolutionarily irrelevant, regardless what relative advantage or disadvantage they might impart.
Granted, in the case of attached/detached earlobes, the trait does appear to be genetic in nature (but as evolutionarily significant as the color of one’s eyes); it is simply worth noting that this is not always the case.
Germans (at least the ones I know) are convinced that people without detached earlobes are more likely to be criminal or some how not as good as those folks with detached earlobes. YMMV.
It’s misguided to think evolutionary process would lead to one earlob being favored over another, just as it would be misguided to think that everyone should have one color for hair, skin, eyes…that every tongue could be rolled…that no one was colorblind, etc.
Earlobs are different…we have attached and detached. This is supporting evidence that helps demonstrate how earlobs being attached or detached have no relevance to survival (and survival means hanging around long enough to reproduce and having offspring that can do the same).
If attached earlobs scared away potential mates, or if they somehow were related to poor survival rates of newborns, I’m sure we wouldn’t be here talking about them because…ta da…they wouldn’t be found on anyone.
It’s a catch-22, old chum.
So,
After reading all the posts, then it seems that the earlobe must be a genetic trait. Is this true then? Eye color, hair color and the rest are passed on through the genes. I never thought this was true of earlobes, but if we follow the logic above, then it must be true.
WAG: my housemates and I were discussing this the other day, and we thought that perhaps there some relation to the need for multi-directional hearing when hunting etc in the past. Loose earlobes perhaps permit more mobility and thus are better at direction-finding. Maybe those people with fixed lobes are able to collect more sound coming from in front of them, and are therefore better equipped to communicate in a speech-driven society.
Quite possibly way off the mark (particularly 'cos it’s hard to see that it would make that much difference) but it’s the best we were able to come up with. 
I remember learning in high school biology that attached/detached earlobes were a classical Medellian pair, but I can’t remember which is dominant and which recessive. Not much help, I guess.
Detached earlobes are the dominant allele.
Is there any correlation between ethnic groups and earlobes? Do people of certain decent have a genetic bias towards one form over the other or are the rate of occurrence for attached / detached earlobes pretty much constant across all ethnic boundaries?