Sex and understanding nature

2011-04-25

in Photography, Rants, Science

Walking around the other day, observing the slow emergence of spring, it occurred to me that there is another whole set of reasons to provide children with early and accurate sexual education, aside from their important right to understand their own bodies.

Briefly, it is impossible to understand nature, history, or biology well without knowing about sex. Why do plants have flowers? Why do birds and insects fly between them? Why do animals form pairs? Why do some species of bird have males that look very different from females (displaying sexual dimorphism)? Why is there such a variety of life forms on Earth? Conversely, why are there so many similarities between life forms on Earth? What defines the human species?

None of these questions can be answered in a satisfactory answer without reference to sex. Plants have flowers because sexual selection helps produce diversity, which improves survival odds. Plants bribe more mobile creatures into carrying around their sex cells (pollen), paying the bribe in the form of nectar. Animals often form pairs to ease the burden of parenting. Sexual dimorphism is reflective of differing investment costs in reproduction between sexes, as well as the way in which sexual selection can drive evolutionary development. Sexual reproduction has contributed to biological diversity, and yet the fact that many organisms need to perform the same basic tasks explains some of their similarity. Humans are the set of organisms that can mate and produce fertile offspring with one another.

Any understanding of nature that excludes sex is sure to be terribly impoverished. As such, it seems foolish to delay telling children about it until they themselves are starting to reach sexual maturity. It seems much better for it to be a fact of life they have learned accurate things about all along.

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{ 3 comments… read them below or add one }

anon April 25, 2011 at 9:12 pm

“Any understanding of nature that excludes sex is sure to be terribly impoverished. As such, it seems foolish to delay telling children about it until they themselves are starting to reach sexual maturity.”

I’m not sure if it strong enough to say “terribly impoverished”. That would imply that you could understand something about nature without the role of reproduction in nature. Nature, or at least “life”, doesn’t make any sense at all without reproduction. Nature without sexuality needs God, and needs him desperately to give some sense of why things are the way they are.

. April 25, 2011 at 11:03 pm

Evolution of sexual reproduction
From Wikipedia, the free encyclopedia

The evolution of sexual reproduction is currently described by several competing scientific hypotheses. Many groups of organisms, notably the majority of animals and plants, reproduce sexually. The evolution of sex contains two related, yet distinct, themes: its origin and its maintenance. However, since the hypotheses for the origins of sex are difficult to test experimentally, most current work has been focused on the maintenance of sexual reproduction.

It seems that a sexual cycle is maintained because it improves the quality of progeny (fitness), despite reducing the overall number of offspring (the twofold cost of sex). In order for sex to be evolutionarily advantageous, it must be associated with a significant increase in the fitness of offspring. One of the most widely accepted explanations for the advantage of sex lies in the creation of genetic variation. Another explanation is based on two molecular advantages. First is the advantage of recombinational DNA repair (promoted during meiosis because homologous chromosomes pair at that time), and second is the advantage of complementation (also known as hybrid vigor, heterosis or masking of mutations).

For the advantage due to creation of genetic variation, there are three possible reasons this might happen. First, sexual reproduction can bring together mutations that are beneficial into the same individual (sex aids in the spread of advantageous traits). Second, sex acts to bring together currently deleterious mutations to create severely unfit individuals that are then eliminated from the population (sex aids in the removal of deleterious genes). Last, sex creates new gene combinations that may be more fit than previously existing ones, or may simply lead to reduced competition among relatives.

. April 24, 2017 at 4:34 pm

Evolutionary determinists suggest that females are a resource that males fight over. A female’s reproductive output is limited by her physiology no matter how many mates she has. A male’s is limited by the number of females he can inseminate. Because of this, males are more likely to seek status, take risks and fight rivals in order to woo as many fertile partners as possible. Females either choose the winners, or the winners choose them, depending on the species. But tell this to the wildly promiscuous female Savanna baboon or the fiercely competitive female bush cricket. Ms Fine uses studies of behaviour from across the animal kingdom to argue that neither sex has a monopoly on competitiveness, promiscuity, choosiness or parental care. Females who sample widely tend to be more reproductively successful (which is why a lioness may mate up to 100 times a day with different lions during oestrus), and those who jockey for dominance are often rewarded with more food.

Among humans, the conventional view is that men are programmed to act like Casanova. After all, a man can ejaculate 100 times in the time it takes a woman to complete a menstrual cycle. But Ms Fine argues that relentless male promiscuity has limited benefits. Because randomly timed sex will impregnate a healthy woman only around 3% of the time, she finds that a man would have to have sex with more than 130 women just to have a 90% chance of beating the fertility rate of a monogamous couple. This, she notes, may be one of the reasons why a majority of men—like women—say they would prefer to be in a sexually exclusive relationship.

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