Sickle Cell Anemia is a recessive trait that tends to have more problems than benefits.
Define "more" please. How do you measure it?
If it had more problems than benefits it would be selected out of the population would it not? If a person has only 1 copy of the gene it is beneficial in a malarial area. Two copies are a net detriment.
In fact, it has a net benefit to a population in the right circumstances. This is enough to bring the single copy up to about 1/3 of a population. Higher than this and there are too many two copy individuals born.
It isn't so easy to be absolute about what is beneficial and what isn't. One example that appears to be easy is the mutation in a strain of Italians that appears to make them immune to cardiovascular disease (this arose some centuries ago in one individual). Another example that is a bit less clear is the boy who has super muscular development. Being very strong should be beneficial should it not? However, in an environment that has limited food availability it may not be. This selective pressure can reduce the average size of populations under some circumstance (foor shortages) but under other circumstances push a population to larger sizes (cold weather).
How I rationalize it is that all human beings, regardless of where they live, need oxygenated blood cells, even those who live in an malaria-stricken area
I read that those with only one copy of the allele are asymptomatic as far as anemia is concerned but much more (or completely?) resistant to malaria.
That all depends on how long sickle-cell anemia has been around. If we can definitively conclude that it has been around for centuries upon centuries then, yes, what you say is true. But if this is a relatively new mutation, then we wouldn't expect it to be selected out or in just yet.
Genetics suggests it has been around for 60 to 150 thousand years.
How would this be the case? Wouldn't it be the opposite? If Africans tend to procreate with other Africans, then the more people who have the heterozygous trait run a greater risk of procreating with someone with the same condition, so that their children might be the homozygous carrier. Would not that homozygous trait increase as population increases?
That is why with the balance of the selective pressure of malaria (very high) and the selective pressure of those who are homozygotic (even higher) the percent of carriers levels out at about 1/3. It is not dependent on population size at all.
So I can't point you to a place which will tie this all together with a bow, science doesn't usually work like that, but I can certainly elaborate on evo-devo if you like, and direct you to the primary literature which discusses these things.
I would stick my neck out and say that the primary literature is never the right place to direct someone unless they are a professional (or RAZD).
That is a bit strong since I can get a fair amount out of it myself but only part of the time and only with some difficulties. But I am pretty well read in a number of areas.
For example your post presumes too much understanding of what terms like "homologue" etc are. I think you have to spell it out a bit more.
(a) How did that thing evolve? (b) What is this thing and what/who made it?
Since we know what designed things and evolved things look like and the differences are very great so it is easy to tell (but not for someone without benefit of the right education) that this is not an evolved thing.
If I see an new animal or plant(but dead like the car is if I don't have the key). I can quickly see it is an evolved thing and not a designed thing.
We know this because (unlike the uneducated individual) we understand the nature of the evolutionary process and the kind of results we get from it. Those results are nothing like things we know are designed and in fact are human designed which is the only example of deliberate design we have.
One clue for those interested in design is just how very bad the design of an evolved thing is in the sense of it's inefficiency and complexity. Another clue maybe the extremely precise fit of the evolved thing to the immediate requirements (stay alive).
I don't agree with that. That is pure assumption for anyone living in pre-Darwinian times would almost never come to such a conclusion.
Of course, it is unlikely that someone in pre-Darwinian times would be able to see the difference. That is the point. We now have an understanding of the nature of the evolutionary mechanisms and we can even use them to generate outcomes. We have the knowledge to allow us to examine the nature of the car and an animal and see that one is a very good match for the end of one process and the other a very good match for the end of an utterly different process.
Why would you bring up the "pre-Darwinian" times when it is not relevant to our current state of knowledge?
There are some organisms in the world that simply defy a Darwinian explanation...especially those that have not only do not have transitional forms in the fossil record, there are not fossils of them yet discovered. Like:
Your example in no way defies a Darwinian explanation. It also matches the outcome of evolutionary processes.
Why does it matter if we have the detailed steps or not? It still matches the pattern we expect. It's genetics still fit within the overall pattern of all life. There is nothing anomalous about it. It is simply one of many, many things for which we don't have good fossils.
You wouldn't make that comment if you knew anything about taphonomy(google it).