"Slanted" Eyes in Orientals

Maybe I'm misreading you: It seems like you're saying that species with outrageous sexual structures/displays/behaviors will eventually (or are more likely to) select themselves to extinction (again, sorry if that is a misinterpretation).This flies in the face of selection - if a subset of a species became too outrageous in their sexual selection to the point survival was reduced, they should be selected against.It would seem that overinvestment in a 'sexual selection handicap' might be a detriment to adaptability in the short term - so such species might be more likely to suffer during habitat loss, climate change, novel predator introduction (esp. humans, who preferentially hunt animals with the largest sexual-attraction structures...), etc.But that is true for over-specialization in general - it's just in this case the specialization is in sexual selection instead of food or ecological niche.

I've heard possibilities for the selection of 'slanted' or 'double-lidded' eyes of Asian populations.The most plausible is that the trait developed in the North or high-elevations (Himilayas?) as protection from cold climate and/or snow/sandstorms - think Siberia/Mongolia, the Iniuts and other native peoples of the northern reaches of North America and Asia. The trait spread by migration.I did a quick search and only found:
http://www.raceandhistory.com/historicalviews/rgh.htmThe article points out that some groups in Southern
Africa have similar eyes - possibly evolved separately (sandstorms as selection?).I'd be interested to hear what others think...

Right - I thought we'd be in agreement...I just wanted to get across my thought that sexual overspecialization isn't a detriment to species survivability any more than other forms of overspecialization.

Maybe you could clarify that it is "self-imposed".Do female birds (of the species that follow such selection) "willfully", intelligently, decide to mate with a male - with the thought "his huge feathers are obviously cumbersome and that he survived despite them is a testament to his fitness."I believe that it is simple inherited behavior (therefore without willful choice); unless you have info to the contrary...

I'm not disputing that selection occurs in this way - as in your scissortail example.I think it is more a matter of language - terms like "self-imposed" and "willful ignorance" make it seem as though the individual females had the choice to choose, indeed that they had the knowledge of the handicapping nature of the trait they were selecting.It seems the true case is females (almost) always choose males with long tails - likely due to genetically defined behavior. If it is "self-imposed", it's more on the species-level than an individual level - and then I don't know that the term "self-imposed" is warranted, perhaps "genetically predisposed".

Right - behavior is not necessarily solely the product of genetics in this case; but I still think that talking about free will and choice in individual birds as self-directing selection is incorrect.Does a koala self-impose specialization on itself because it refuses to use anything other than eucalyptus as a food source? I don't believe that is an individual choice on the part of each koala - just as I don't believe individual birds decide if they prefer long or short tails in each case.In fact, if an anamolous female scissortail existed that selected short tails, or selected indiscriminately, I would propose an underlying genetic cause.How much sexual choice is genetically driven? Much of it, it would seem, if the results from the study you described are extremely consistent.

I agree completely - I've attended many seminars where the researcher will discuss racial differences epidemiologically, as in "African-Americans are more likely to die from colorectal cancer", but when it comes time to analyze the human genetic data later in the seminar, refuses to split the data along race lines. I understand that much of the influence may be socioeconomic, but it is highly unlikely that there is zero genetic influence there - it is a shame that it doesn't get studied given the therapeutic implications.Like you said, it is not racist, at least until someone states that Asians are superior or inferior for having double-lidded eyes (and now that I'm writing this, I believe that someone did state that earlier in the thread...)Did you read message 34 in this thread? Since you seem interested in returning to the human topic?

Okay, so that is the basis of the difference in your view... But are you saying we still should not study the environmental and genetic differences? I'm not just talking about eyes here; here is a real example:There is currently a class of drugs called EGFR inhibitors in cancer clinical trials in the US, Europe, and Japan. Interestingly, lethal pulmonary fibrosis has been found to be a side-effect only in the Asian patients. Should we study why? Perhaps learn which individuals will sucuumb to the side-effect? It could save many lives (especially if the drug is banned because of the potential side-effects and others don't reap the benefits.)

Wow. For some reason I am surprised to hear you being a proponent of reproductive isolation, ecological niche specialization, and above all, natural selection. I didn't take you for an evolutionist, but apparently you are (albeit it in Biblical terms...)But from a previous post it seemed that you were saying we shouldn't study ethnic-based differences in biology - but you use that here, so I must have misread you there, also...

You're not an evolutionist? - Alymeda, you have me really confused now. To quote your earlier message: Colonization of new ecological niches leads to specialization and changes in phenotypic "characteristics from changes in genetics," presumably due to selection by the "different environments." New sub-species coming into existence (hopefully I'm not offending by calling ethnic groups sub-species - just trying to make a point; though truthfully other species with the number of differences as a Mongolian and a sub-Saharan African may qualify as separate species or sub-species). Reproductive isolation due to behavioral differences. (Language differences as you describe them here qualify as reproductive isolation - for example, different cricket species are known that could mate simply based on reproductive biology, but never do because they use different song patterns to attract mates. Hence reproductive isolation.) Here you bring up natural selection again, by the "new and different climate zones." And you close your reply by reiterating the importance of reproductive isolation to the differences we see in humans today.Almeyda, whether or not you choose to admit it, you're laying down the theory of evolution through biblical teachings. Hopefully my line-by-line analysis helps you understand this. I wanted to make sure I wasn't reading into what you wrote, but your line, slightly paraphrased: You've basically defined evolution here, right down to the "changes in genetics."After your input I may use the Babel story as biblical proof of evolution in future discussions.Thanks.

I believe you have the definition of evolution quite incorrect. Here is the version given in this forum's glossary: Please think about this definition and reread your comments in this thread - you have supported evolution as scientifically defined. You've given no evidence for creation yet, only refutation of evolution while apparently unwittingly supporting it. You claim that "animals stay stagnant" as evidence for creation, but above describe the evolution of differences in humans.Perhaps most importantly, if you want to use the term "kind," you absolutely must give a definition of it for this debate to be valid. Without a valid definition we cannot begin to discuss where one kind ends and another begins...

You state: I think you are defending yourself through the concept of existing genetic variance in the founder population, but referring to one of your earlier posts: Here you admit mutation-based change in reproductively isolated groups resulting in changes in features. This is evolution. I repeat: You are very concerned about whether you consider a genetic change "degenerative" or not. That has nothing to do with defining whether or not evolution has occurred, and is a subjective term (loss of pigment may be thought of as "degenerative" at the equator, but "progressive" closer to the poles).If you want to get technical, "changes in allele frequencies" can be substituted for "genetic changes". It doesn't matter if the allele frequencies change because of introduction of new alleles (mutation) or because of selection changing existing proportions of existing alleles.A reply to the issue of "kind" will follow.

Thank you for providing a specific definition of "kind." I commend you for doing so. Here is your definition: So it follows, if I could show you a species, that upon a genetic mutation, split into two separate populations incapable of interbreeding, that would be evidence of one kind splitting into two, and thus provide some proof of evolution.Well, here it is: The researchers witnessed a speciation event in a closed population they were studying, a single gene mutation changed the shell pattern of a snail, and the constraints of the new shell shape prevent the snails with the two types of shells from aligning their genitals to mate. But, the old-shelled snails could mate with the old-shelled, and the new-shelled could mate with other new-shelled snails.Thus snails with the shell-changing mutation are incapable of "interbreeding" with the ones without the mutation - even if they are sitting next to each other in the same pond.I think the snail example is powerful: Humans witnessed it, it is based on a single gene mutation, that mutation prevents mating between those with and without the mutation (reproductive isolation), and the shell pattern is visibly different (morphology difference).I'll be interested to hear what your response is.I hope it is not, "But it's still a snail."That would violate your definition of "kind".

I guess you didn't read the scientific definition I gave you (twice) otherwise you would realize that "evolving into higher more complex life" is not part of it. I'm sure you'll deny it by your incorrect VCR tape analogy, but duplication and rearrangement at chromosomal and smaller genetic units is a means to increase the "genetic information."I think your misconception on this point comes from the idea that: if a gene is copied, you'd just have two copies of the same gene, and therefore nothing new would come of it.If so, you are not thinking about what happens later, as the two copies of the gene accumulate different mutations, and diverge in function. Indeed, evolution predicts that one copy of the gene would be lost if no changes occurred since completely redundant function would leave no selective force to have both copies.This is why we have what are called "gene families," a simple example being the ERBB receptor family. It has four members, duplicated from a single ancestral ERBB receptor gene, but each member has since changed sequence, and hence function. Thus the receptors' ligand specificities have diverged, as has their downstream signaling pathways. Overtly, ERBB2 has a dysfunctional ligand-binding domain, while the ERBB3 has an inactive kinase domain. Loss of any one ERBB results in embryonic lethality. ("Lower" organisms like the fruit fly and nematodes have one ERBB gene homologue.)Also, duplications and rearrangments can "remix" existing genes, coding for hybrid proteins with functions from each of the original proteins. These hybrid genes can accumulate mutations.Also, duplications/rearrangments can leave gene coding sequence intact, but change regulatory elements associated with the gene, causing it to be expressed in a new tissue site, or at a different level.So, it is not that every single gene has arisen by chance. Most genes are made up of domains that have similar sequence and produce protein domains with similar function. Thus, only one ancestral kinase domain could have been duplicated to produce the hundreds of different genes containing a kinase domain.Imagine a gene with an extracellular domain that attaches to something outside of the cell. Duplication, rearrangment, and now a new hybrid gene exists with an extracellular binding domain and a cytoplasmic kinase domain - a kinase receptor is born...This kinase receptor can duplicate, rearrange, mutate; and now you have a family of several kinase receptors...

Almeyda - firstly, this is nothing like a human being born sans genitalia, because that would likely result in sterility, not just reproductive isolation.Further more, you haven't readdressed your definition of "kind". My snail example meets your definition, which stated: It seems like you are taking back this definition of kind, so I would like your revised version so that we can continue the debate. I did, in message #73 of this thread:
http://EvC Forum: "Slanted" Eyes in Orientals -->EvC Forum: "Slanted" Eyes in OrientalsYou haven't addressed this post yet, and I would be interested in your thoughts.