Questions about genders ... male/female

[DeistPaladin]

Sorry I've not posted in several days. The classes I'm teaching are new, so there's a lot to prepare each week. I've read all of the responses and shared them with my students last week. They appreciated the feedback. If it's alright, I'd like to post questions that the students may come up with or need clarification as we cover different topics. We are just seeking to comprehend.

Sorry I'm late to the party.

What Evolution Is and Is Not
Regarding the first question, I think we need to emphasize that evolution is not about whether or not there is a god. Evolution could involve a yet-undetected deity that oversees the process. Science doesn't deal with this because it only concerns itself with the natural universe, or that which can be studied.

Neither is the case that Creationism is necessarily a reference to the Christian god (one can be a Muslim Creationist, a Hindu Creationist, etc.).

Evolution, in my layman's understanding, boils down to two observations:

1. Life changes over time.
2. Changes that benefit survival or adaptation to a given environment will be more likely to be passed on.

In my home state of Kentucky, horse breeding is a profession we're known for (and for our famous springtime horse race). We breed horses to be faster. This is "artificial selection", where humans interfere with the process, but "natural selection" the driving force of evolution, works the same way only over longer periods of time.

Why Two Genders?
There are biological advantages and disadvantages to both asexual reproduction and sexual reproduction.

Advantages of Asexual Reproduction
1. It's quick and easy. A cell divides into two cells. Done.
2. It only takes one organism.

Advantages of Sexual Reproduction
1. Greater variation in offspring as two sets of genes are mixed and matched.
2. Said variation results in more changes in fewer generations, thus greater adaptability as the environment changes.
3. Some genes can be "recessive", carried by the organism, to be passed on and possibly appear in later generations, and thus retained by the gene pool to allow for greater variation.

Greater variation = quicker adaptation = biologically beneficial
...but, to quote the Sonny and Cher song, "It takes two, baby"

Why Not More Genders?
More genders would increase the variations even more, that is true, but as with all things, there is a diminishing return of benefits and an increased cost at each level. Already, sexual reproduction is more "complicated" than asexual reproduction.

Consider the time and energy we spend finding the right partner. Then think of all we go through managing a relationship with that partner. Now multiply that with a third gender. And again with a fourth. Etc.

The genetic variation gained by such increased complication would likely not be worth the added complication. Two gender reproduction already yields a suitable variation in the mixing and matching of genes.

The next question: (we now understand why we didn't evolve into 7 or 7000 "sexes") ... is at what point did we go from being asexual to being sexual (2 sexes) in order to reproduce?

Well, we haven't really. Asexual reproduction still takes place in simple life forms on the planet. Single cell organisms, bacteria, maybe fungus.

At least some plant life does have male and female characteristics, playing a role in reproduction. I remember studying in school that the early research on genes was conducted by Gregor Mendel. To get around the moral issues of studying sexual reproduction in animals, he restricted himself to the study of plants. This was where we discovered "dominant" vs. "recessive" genes and how they are passed down through the generations.

Worms, by the way, are hermaphroditic. When two worms run into each other while crawling through the ground, they gain the greatest biological advantage by impregnating each other.

So as we move from single cell organisms to plant and animal life, it seems we find more examples of sexual reproduction and fewer of asexual reproduction. Exactly what are the most complicated of organisms that still have asexual reproduction, a biologist can answer better than me.