Saturday, April 18, 2020
Reproduction A Courting To Nature Essays (902 words) - Mating
  Reproduction: A Courting To Nature      ======================================================================  REPRODUCTION: A-Courting to Nature!         LIFE SCIENCES SIG  ----------------------------------------------------------------------  For some time she had watched his movements, appearing coyly in his  haunts. And now, had it paid off? Doubtless, he was in love. His  muscles were taut; he swooped through the air more like an eagle  than a Greylag gander. The only problem was, it was not for her that  he then landed in a flurry of quacks and wingbeats, or for her that he  dashed off surprise attacks on his fellows. It was, rather, for  another - for her preening rival across the Bavarian lake.    Poor goose. Will she mate with the gander of her dreams? Or will  she trail him for years, laying infertile egg clutches as proof of her  faithfulness? Either outcome is possible in an animal world  marked daily by scenes of courtship, spurning and love triumphant.  And take note: these are not the imaginings of some Disney screen-16  writer. Decades ago Konrad Lorenz, a famed Austrian naturalist,  made detailed studies of Greylags and afterwards showed no  hesitation in using words like love, grief and even embarrassment to  describe the behavior of these large, social birds.    At the same time he did not forget that all romance - animal and  human - is tied intimately to natural selection. Natural selection  brought on the evolution of males and females during prehistoric  epochs when environmental change was making life difficult for  single-sex species such as bacteria and algae. Generally, these  reproduced by splitting into identical copies of themselves. New  generations were thus no better than old ones at surviving in an  altered world. With the emergence of the sexes, however,  youngsters acquired the qualities of two parents. This meant that  they were different from both - different and perhaps better at  coping with tough problems of survival. At the same time, nature  had to furnish a new set of instincts which would make "parents"  out of such unreflective entities as mollusks and jellyfish..    The peacock's splendid feathers, the firefly's flash, the humpback  whale's resounding bellow - all are means these animals have  evolved to obey nature's command: "Find a mate. Transmit your  characteristics through time!" But while most males would accept  indiscriminate mating, females generally have more on their minds.    In most species, after all, they take on reproduction's hardest  chores such as carrying young, incubating eggs and tending  newborns. Often they can produce only a few young in a lifetime.  (Given half a chance, most males would spawn thousands.) So it's no  surprising that the ladies are choosy. They want to match their  characteristics with those of a successful mate. He may flap his  wings or join a hockey team, but somehow he must show that his  offspring will not likely be last to eat or first in predatory jaws.    Strolling through the Australian underbrush that morning, she had  seen nothing that might catch a female bowerbird's eye. True,  several males along the way had built avenue bowers - twin rows of  twigs lined up north and south. True, they had decorated their  constructions with plant juices and charcoal. Yet they displayed  nothing out front! Not a beetle's wing. Not a piece of flower.  Then she saw him. He stood before the largest bower and in his mouth  held a most beautiful object. It was a powder blue cigarette  package, and beneath it there glinted a pair of pilfered car keys.  Without hesitation she hopped forward to watch his ritual dance.    Males have found many ways to prove their worth. Some, like  bowerbirds, flaunt possessions and territory, defending these  aggressively against the intrusion of fellow males. Others, like  many birds and meat-eating mammals, pantomime nest building or  otherwise demonstrate their capacity as dads. Still others,  however, do nothing. Gentlemen may bring flowers, but most male  fish just fertilize an egg pile some unknown female has left in  underwater sand. For a fish, survival itself is a romantic feat.  For other species, though, love demands supreme sacrifices.    Shortly after alighting on the back of his mate, the male praying  mantis probably had no idea what was in store. This would have  been a good thing too, because as he continued to fertilize his  partner's eggs, she twisted slowly around and bit off his head. She  continued to put away his body parts until well nourished and thus  more able to sustain her developing young.    Luckily for most species, the urge to mate come on only  occasionally, usually in springtime. For love can hurt, particularly  if you intended has difficulty telling a mate from a meal. Pity the  poor male of the spider species, Xysticus Cristatus, for instance.  His only    
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