Does evolution have an answer for how independent male and female sexes originated?

Yes, of course it has an answer.

First, I would urge caution with the word "independent." Males and females are *absolutely* dependent on each other. And the evolution of each is absolutely dependent on the evolution of the other. Changes to one sex, needs to be matched by changes to the other ... any change that produces a significant incompatibility to the other doesn't last long.

So I think you are trying to say "specialized." As in males and females having distinct differences that makes them suited only to being males or females.

Second, I would point out that there are two separate parts to this question ... the evolution of sexual reproduction, and the evolution of specialized 'males' and 'females'.

In other words, it is important to remember that you can have sexual reproduction without males and females (with abundant examples from both the plant and animal world shows us).

So start with an understanding of what sexual reproduction is, and what males and females are ... and then it is quite easy to see the progression of advantages that would lead to males and females.

Sexual reproduction is the alternation between diploid and haploid forms of a species. For example, we humans think of ourselves as diploid creatures (our cells all contain a double-set of our chromosomes). But for *reproductive* purposes, we generate haploid cells (sex cells, with a single set of chromosomes) that combine with the haploid cells of other individuals (fertilization) to produce a new diploid cell (zygote) that starts a new individual.

Once you understand that, then the evolution of sexual reproduction very early in the history of life, can be broken down into the events that would have produced each of these stages, and the advantages that such an event would have had that led to its propagation into many species. Haploid cells (single chromosome set) came first. Then diploid cells through interrupted cell division (the chromosomes replicated, but the cell division did not complete, resulting in a cell with a double-set) ... the advantages of which are that every gene now has a backup). Then organisms that can switch back and forth between diploid and haploid stages depending on resources (for a modern example, look at volvox, or the slime mold amoeba). And finally the well-known advantages that this system produces not only when resources get scarce, but as the normal way of reproduction (far superior production of stable genetic diversity ... every individual is a unique combination of genes different from either of its parents).

'Male' and 'female' with respect to *gametes* (sex cells) mostly refers to size. They are both haploid forms of the organism ... but male gametes (sperm or pollen) are smaller and more motile, and thus optimized for mass-production, and desemination into the environment (the very word 'desemination' comes from the "spreading of seed"). Female gametes (egg cells or ova) are larger and less motile, and are thus optimized for fertilization and subsequent cell division. Once fertilized, they have all the ingredients to survive without nutrients long enough to begin cell division.

So the evolution of male and female gametes is just one of the haploid cells slowly differentiating into small and large forms. Some becoming smaller and more motile, and others becoming larger and less motile. Individuals can even produce both kinds (again, see plants for an obvious example).

'Male' and 'female' with respect to *individuals* in a multicellular organism, refers to whether they have organs specialized for producing male or female gametes. So again, the evolution of male and female individuals is just one of slow specialization into two forms, because this specialization has advantages (less embyological energy spent producing the organs needed to produce both kinds of sex cells).

>"Did the independent sexes come into play during the Arthropods portion of our evolution?"

We never had an "arthropod portion" of our evolution. Arthropods and vertebrates came from two very different branches of evolution (protostomes vs. deuterostomes), and sexual reproduction, including separate males and females, came much earlier.

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Niebling illustrates the tragedy of Creationism ... the scientific defeatism needed to maintain the "evolutionists are stumped" attitude, that leads to an utter lack of *CURIOSITY* about interesting questions!

Perhaps if Creationists like Niebling would spend just a LITTLE time reading something other than sites like 'trueorigin.orgn' that are committed to the position that 'evolutionists' are constantly "stumped" ... then maybe they would appear at least *interested* in the question!

"Does evolution have an answer for how independent male and female sexes originated?"

Incremental specialisation accumulating across the generations, as worked upon by natural selection.

"As I look at the progression of single cell organisms to humans, I'm not quite sure where male and female comes into play."

Um, among single cell organisms, many of which have sexual reproduction.

"Did the independent sexes come into play during the Arthropods portion of our evolution?"

No. They developed among single-celled eukaryotes.

There is nothing at all difficult to understand about the natural evolution of the sexes. Even relatively simple organisms like bacteria sometimes reproduce by a type of sexual means, such as plasmid conjugation where one bacteria may extend a 'pilus' and connect with a second bacteria. It is through this pilus that a plasmid vector containing genes get exchanged. Bacteria A shares genes with Bacteria B. From there, time, natural selection and evolution does the rest.

It's not to hard to see that, over long periods of time and evolution, plasmid exchange between simple species would naturally lead to more complex sexual interactions between more complex life forms.

See: Conjugation

http://www.emunix.emich.edu/~rwinning/genetics/bac...

Evolutionists freely admit that the origin of the sexual process remains one of the most difficult problems in biology.

Most evolutionists would argue that there is an underlying reason why evolution produces certain biological processes and characteristics in particular organisms... that is, there is some selective advantage for an organism to develop some process or genetic trait that promotes its survival. This is a postulate put forth in 'Darwinian' theories.

Evolutionary biology is unable to reveal why animals would abandon asexual reproduction in favor of more costly and inefficient sexual reproduction, but many people could come up with a number of hypotheses to support such a progression... The problem arises in providing an explanation that is consistent with what we know about genetics and patterns of evolution.

I would say that the jury is still out on this question and that we may never understand it.