The Unsorted BBS Collection/thegreatunsorted.tar/thegreatunsorted/texts/term_papers/reprodct.txt

Text File | 1995-03-31 | 6KB | 104 lines

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REPRODUCTION: A-Courting to Nature!                  LIFE SCIENCES SIG
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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 hope of survival is to tie a much larger female to the
ground with silk thread, and keep her there.

Every time a moth releases its attracting scent, or a bullfrog sings
out its mating call, these animals are risking a blind date with some
predator.  Such alluring traits have long puzzled scientists,
particularly those which seem not only risky but useless as well.
Why, after all, should a frigate bird mate more if he puffs out an
extra large red throat sac?  How does ownership of such a thing
indicate a superior individual?  Until recently, the question stymied
biologists, but then researchers in the U.S. and Sweden announced a
possible answer.  While studying widowbirds, among whom
extravagant tail feathers are hip, they discovered that the
longest-tailed males also carried a lower number of blood parasites.
Sexual ornamentation seemed to be a means by which males could
show of superfluous health and energy.

All of which may bring us to fast sports cars, flashy clothes and
other accessories of the human suitor.  After all, if he can afford
dinner at the city's most expensive restaurant, chances are he could
finance a baby too.